diff --git a/ChangeLog b/ChangeLog
index 36777db2e..78ff73987 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,12 +1,13 @@
 WeeChat ChangeLog
 =================
 Sébastien Helleu <flashcode@flashtux.org>
-v0.4.0-dev, 2012-10-20
+v0.4.0-dev, 2012-11-02
 
 
 Version 0.4.0 (under dev!)
 --------------------------
 
+* core: add command /eval, use expression in conditions for bars
 * core: add option "-quit" for command /upgrade (save session and quit without
   restarting WeeChat, for delayed restoration)
 * core: fix display of zoomed/merged buffer (with number >= 2) after switching
@@ -15,6 +16,7 @@ Version 0.4.0 (under dev!)
   (problem with nick displayed in first line of screen) (bug #37556)
 * core: fix wrapping of words with wide chars (the break was made before the
   correct position)
+* api: add new function "string_eval_expression"
 * api: connect with IPv6 by default in hook_connect (with fallback to IPv4),
   shuffle list of hosts for a same address, add argument "retry" for
   hook_connect, move "sock" from hook_connect arguments to callback of
diff --git a/NEWS b/NEWS
index 15d704b12..e9cf3719a 100644
--- a/NEWS
+++ b/NEWS
@@ -1,7 +1,7 @@
 WeeChat Release Notes
 =====================
 Sébastien Helleu <flashcode@flashtux.org>
-v0.4.0-dev, 2012-10-16
+v0.4.0-dev, 2012-11-02
 
 
 Version 0.4.0 (under dev!)
@@ -9,6 +9,10 @@ Version 0.4.0 (under dev!)
 
 Important release notes:
 
+* conditions in bars have changed, and now an expression is evaluated.
+  If you have a value with many conditions in a bar, like: `nicklist,active`,
+  you must now use an expression like: `${nicklist} && ${active}` (see
+  the chapter about bars in the 'WeeChat User's guide').
 * IPv6 is now used by default to connect to IRC servers, with fallback to IPv4.
   The option irc.server_default.ipv6 is now "on" by default. If IPv6 is not
   enabled or fails, IPv4 will be used. The "ipv6" option in server is now used
diff --git a/doc/de/autogen/plugin_api/hdata.txt b/doc/de/autogen/plugin_api/hdata.txt
index f5302dd5b..f6a441e0d 100644
--- a/doc/de/autogen/plugin_api/hdata.txt
+++ b/doc/de/autogen/plugin_api/hdata.txt
@@ -325,8 +325,6 @@
 | weechat | bar | Bar |
   'name' (string) +
   'options' (pointer) +
-  'conditions_count' (integer) +
-  'conditions_array' (string, array_size: "conditions_count") +
   'items_count' (integer) +
   'items_subcount' (pointer) +
   'items_array' (pointer) +
diff --git a/doc/de/autogen/user/weechat_commands.txt b/doc/de/autogen/user/weechat_commands.txt
index 9e4780cfc..f1dffb0ec 100644
--- a/doc/de/autogen/user/weechat_commands.txt
+++ b/doc/de/autogen/user/weechat_commands.txt
@@ -11,49 +11,50 @@ message: Abwesenheitsnachricht (ohne eine Nachricht wird der Abwesenheitszustand
 [command]*`bar`* Infobars verwalten::
 ........................................
 /bar  list|listfull|listitems
-      add <name> <type>[,<cond1>[,<cond2>...]] <position> <size> <separator> <item1>[,<item2>...]
+      add <name> <type>[,<condition>] <position> <size> <separator> <item1>[,<item2>...]
       default [input|title|status|nicklist]
       del <name>|-all
       set <name> <option> <value>
       hide|show|toggle <name>
       scroll <name> <window> <scroll_value>
 
-         list: listet alle Infobars auf
-     listfull: listet alle Infobars detailliert auf (Standardaufruf)
-    listitems: listet alle Items auf, die in den Infobars genutzt werden
-          add: füge eine neue Infobar hinzu
-         name: Name der Infobar (muss einmalig sein)
-         type:   root: außerhalb des Fensters,
-               window: innerhalb des Fensters, mit optionalen Merkmalen (siehe unten)
-    cond1,...: Merkmal(e) für eine Infobar (nur nutzbar mit der Type-Option "window"):
-                 active: in einem aktiven Fenster
-               inactive: in einem inaktiven Fenster
-               nicklist: in Fenstern mit einer Nickliste
-               werden keine Merkmale angegeben, ist die Infobar immer sichtbar
-     position: bottom (unten), top (oben), left (links) oder right (rechts)
-         size: Größe der Infobar (in Zeichen)
-    separator: 1 um eine Trennlinien zu zeichnen, bei 0 oder ohne eine Angabe wird keine Trennlinien gezeichnet
-    item1,...: Items die in der Infobar genutzt werden sollen (Items können durch Kommata oder Leerzeichen getrennt werden ("+" (verbindet Items))
-      default: erstellt standardisierte Infobars
-          del: entfernt eine Infobar (alle Infobars können mit der Option "-all" entfernt werden).
-          set: setzt einen Wert für Infobar
-       option: Option die verändert werden soll (für eine Liste aller möglichen Optionen, bitte folgenden Befehl nutzen: /set weechat.bar.<barname>.*)
-        value: neuer Wert für Option
-         hide: Infobar wird ausgeblendet
-         show: zeigt eine ausgeblendete Infobar an
-       toggle: zeigt/versteckt eine Infobar
-       scroll: scrollt Infobar hoch/runter
-       window: Nummer des Fensters (nutze '*' für aktuelles Fenster oder für die Root-Bars)
- scroll_value: Werte für Scroll-Funktion: 'x' oder 'y', gefolgt von '+', '-', 'b' (Beginn) oder 'e' (Ende), Wert (für +/-), und optional % (zum scrollen der Breite/Höhe in %, ansonsten wird dieser Wert als Anzahl der Zeichen interpretiert um die gescrollt werden soll)
+         list: list all bars
+     listfull: list all bars (verbose)
+    listitems: list all bar items
+          add: add a new bar
+         name: name of bar (must be unique)
+         type:   root: outside windows,
+               window: inside windows, with optional conditions (see below)
+    condition: condition(s) for displaying bar (only for type "window"):
+                 active: on active window
+               inactive: on inactive windows
+               nicklist: on windows with nicklist
+               other condition: see /help weechat.bar.xxx.conditions and /help eval
+               without condition, the bar is always displayed
+     position: bottom, top, left or right
+         size: size of bar (in chars)
+    separator: 1 for using separator (line), 0 or nothing means no separator
+    item1,...: items for this bar (items can be separated by comma (space between items) or "+" (glued items))
+      default: create a default bar (all default bars if no bar name is given)
+          del: delete a bar (or all bars with -all)
+          set: set a value for a bar property
+       option: option to change (for options list, look at /set weechat.bar.<barname>.*)
+        value: new value for option
+         hide: hide a bar
+         show: show an hidden bar
+       toggle: hide/show a bar
+       scroll: scroll bar
+       window: window number (use '*' for current window or for root bars)
+ scroll_value: value for scroll: 'x' or 'y' (optional), followed by '+', '-', 'b' (beginning) or 'e' (end), value (for +/-), and optional % (to scroll by % of width/height, otherwise value is number of chars)
 
-Beispiele:
-  erstellt eine Infobar mit den Items: time, buffer number + name, und Vervollständigung:
+Examples:
+  create a bar with time, buffer number + name, and completion:
     /bar add mybar root bottom 1 0 [time],buffer_number+:+buffer_name,completion
-  versteckt die Infobar (meinebar):
-    /bar hide meinebar
-  scrollt die Nickliste im aktuellen Buffer um 10 Zeilen nach unten:
+  hide a bar:
+    /bar hide mybar
+  scroll nicklist 10 lines down on current buffer:
     /bar scroll nicklist * y+10
-  scrollt zum Ende der Nicklist im aktuellen Buffer:
+  scroll to end of nicklist on current buffer:
     /bar scroll nicklist * ye
 ........................................
 
@@ -199,6 +200,60 @@ infolists: zeigt Information über die Infolists an
   windows: zeigt die Fensterstruktur an
 ........................................
 
+[[command_weechat_eval]]
+[command]*`eval`* evaluate expression and send result to buffer::
+........................................
+/eval  [-n] <expression>
+       [-n] <expression1> <operator> <expression2>
+
+        -n: display result without sending it to buffer (debug mode)
+expression: expression to evaluate, variables with format ${variable} are replaced (see below)
+  operator: a logical or comparison operator:
+            - logical operators:
+                &&  boolean "and"
+                ||  boolean "or"
+            - comparison operators:
+                ==  equal
+                !=  not equal
+                <=  less or equal
+                <   less
+                >=  greater or equal
+                >   greater
+                =~  is matching regex
+                !~  is NOT matching regex
+
+An expression is considered as "true" if it is not NULL, not empty, and different from "0".
+The comparison is made using integers if the two expressions are valid integers.
+To force a string comparison, add double quotes around each expression, for example:
+  50 > 100      ==> 0
+  "50" > "100"  ==> 1
+
+Some variables are replaced in expression, using the format ${variable}, variable can be, by order of prioity :
+  1. the name of an option (file.section.option)
+  2. a hdata name/variable (the value is automatically converted to string), by default "window" and "buffer" point to current window/buffer.
+Format for hdata can be one of following:
+  hdata.var1.var2...: start with a hdata (pointer must be known), and ask variables one after one (other hdata can be followed)
+  hdata(list).var1.var2...: start with a hdata using a list, for example:
+    ${buffer[gui_buffers].full_name}: full name of first buffer in linked list of buffers
+    ${plugin[weechat_plugins].name}: name of first plugin in linked list of plugins
+For name of hdata and variables, please look at "Plugin API reference", function "weechat_hdata_get".
+
+Examples:
+  /eval -n ${weechat.look.scroll_amount}  ==> 3
+  /eval -n ${window}                      ==> 0x2549aa0
+  /eval -n ${window.buffer}               ==> 0x2549320
+  /eval -n ${window.buffer.full_name}     ==> core.weechat
+  /eval -n ${window.buffer.number}        ==> 1
+  /eval -n ${window.buffer.number} > 2    ==> 0
+  /eval -n ${window.win_width} > 100      ==> 1
+  /eval -n (8 > 12) || (5 > 2)            ==> 1
+  /eval -n (8 > 12) && (5 > 2)            ==> 0
+  /eval -n abcd =~ ^ABC                   ==> 1
+  /eval -n abcd =~ (?-i)^ABC              ==> 0
+  /eval -n abcd =~ (?-i)^abc              ==> 1
+  /eval -n abcd !~ abc                    ==> 0
+........................................
+
 [[command_weechat_filter]]
 [command]*`filter`* Filterfunktion um Nachrichten in Buffern aus- oder einzublenden, dazu können Schlagwörter oder reguläre Ausdrücke verwendet werden::
 ........................................
diff --git a/doc/de/weechat_user.de.txt b/doc/de/weechat_user.de.txt
index e8c12c538..c857ca784 100644
--- a/doc/de/weechat_user.de.txt
+++ b/doc/de/weechat_user.de.txt
@@ -555,6 +555,219 @@ Beispiele für eine vertikale und horizontale Fensteraufteilung:
                   (Buffer #3)
 ........................................
 
+// TRANSLATION MISSING
+[[bars]]
+Bars
+~~~~
+
+A 'bar' is an area beside the chat that can contain any type of text.
+
+The bar options can be set with options `weechat.bar.name.option` where `name`
+is the name of the bar and `option` the option for this bar.
+
+List of bar options:
+
+[width="100%",cols="2m,2,10",options="header"]
+|========================================
+| Option | Values | Description
+
+| type | `root`, `window` |
+  A bar with type `root` is displayed exactly one time on screen, outside all
+  windows. There is no root bar by default, but an example is the bar 'buffers'
+  created by script 'buffers.pl' (sidebar with list of buffers). +
+  A bar with type `window` is displayed in each window, for example if you
+  split one time the screen (with `/window splith` or `/window splitv`), you
+  will have one bar in each window. The four default bars ('title', 'status',
+  'input', 'nicklist') have type `window`.
+
+| position | `top`, `bottom`, `left`, `right` |
+  Position of the bar: above/below chat, on the left/right.
+
+| priority | integer ≥ 0 |
+  Priority for display of bar: this is used for ordering the bars on screen when
+  many bars have same type and position. +
+  The bars are displayed from the edge of the screen to the center. A higher
+  priority will display bar at the beginning, so closer to the edge. +
+  Example: 'input' bar has priority 1000, so it is displayed before the 'status'
+  bar, which has priority 500.
+
+| size | integer ≥ 0 |
+  The size of the bar: number of columns for position left/right, number
+  of lines for position top/tobbom. A size of `0` means automatic, so the size
+  will be computed according to content displayed in bar.
+
+| size_max | integer ≥ 0 |
+  The maximum size for a bar, `0` = no limit (this option is used only if
+  `size` = `0`).
+
+| color_bg | color |
+  The default background color for the bar.
+
+| color_fg | color |
+  The default text color for the bar.
+
+| color_delim | color |
+  The color for delimiters in bar.
+
+| hidden | `on`, `off` |
+  When option is `on`, the bar is hidden. +
+  Note: instead of changing this option, the command `/bar` is preferred, for
+  example: `/bar toggle nicklist` (see command <<command_weechat_bar,/bar>>).
+
+| separator | `on`, `off` |
+  When option is `on`, a separator (line) is displayed between this bar and
+  other bars (or chat).
+
+| items | string |
+  A list of 'items' (see <<bar_items,items>> for more info).
+
+| filling_left_right | `horizontal`, `vertical`, `columns_horizontal`, `columns_vertical` |
+  Type of filling for a bar which has position `left` or `right` (see
+  <<bar_filling,filling>> for more info).
+
+| filling_top_bottom | `horizontal`, `vertical`, `columns_horizontal`, `columns_vertical` |
+  Type of filling for a bar which has position `top` or `bottom` (see
+  <<bar_filling,filling>> for more info).
+
+| conditions | string |
+  The conditions to display the bar (see <<bar_conditions,conditions>> for more
+  info).
+|========================================
+
+[[bar_items]]
+Items
+^^^^^
+
+The option 'items' is a string with a list of bar items, separated by a comma
+(space between items on screen) or "+" (glued items).
+
+The list of bar items is displayed with command `/bar listitems`.
+
+Example of bar with items "[time],buffer_number+:+buffer_plugin+.+buffer_name":
+
+........................................
+┌─────────────────────────────────────────────────────────────────────────────────────────┐
+│[12:55] 3:irc/freenode.#weechat                                                          │
+└─────────────────────────────────────────────────────────────────────────────────────────┘
+........................................
+
+[[bar_filling]]
+Filling
+^^^^^^^
+
+There are four types of filling:
+
+* `horizontal`: the items are displayed horizontally, from left to right. If
+  there are new lines in items, a space is used to separate lines.
+* `vertical`: the items are displayed from top to bottom. If there are new
+  lines in items, a new line is used to separate lines.
+* `columns_horizontal`: items are displayed using columns, where text is
+  aligned on the left. The first item is on top left, the second is on same
+  line, on the right.
+* `columns_vertical`: items are displayed using columns, where text is aligned
+  on the left. The first item is on top left, the second is one line below.
+
+Default bars 'title', 'status' and 'input' have 'horizontal' filling, and
+default bar 'nicklist' has 'vertical' filling.
+
+Some examples of filling for bar 'nicklist':
+
+........................................
+┌──────────────────────────────────────────────────┐
+│Welcome to #test, this is a test channel          │
+│12:54:15 peter | hey!                    │@carl   │
+│12:55:01  +Max | hello                   │@jessika│
+│                                         │@maddy  │
+│                                         │%Diego  │
+│                                         │%Melody │
+│                                         │+Max    │
+│                                         │ celia  │
+│                                         │ Eva    │
+│                                         │ freddy │
+│                                         │ Harold^│
+│                                         │ henry4 │
+│                                         │ jimmy17│
+│                                         │ jodie ▼│
+│[12:55] [6] [irc/freenode] 3:#test(+n){24}        │
+└──────────────────────────────────────────────────┘
+                filling_left_right = vertical ▲
+
+┌──────────────────────────────────────────────────┐
+│Welcome to #test, this is a test channel          │
+│12:54:15 peter | hey!           │@carl     lee    │
+│12:55:01  +Max | hello          │@jessika  louise │
+│                                │@maddy    mario  │
+│                                │%Diego    mark   │
+│                                │%Melody   peter  │
+│                                │+Max      Rachel │
+│                                │ celia    richard│
+│                                │ Eva      sheryl │
+│                                │ freddy   Vince  │
+│                                │ Harold^  warren │
+│                                │ henry4   zack   │
+│                                │ jimmy17         │
+│                                │ jodie           │
+│[12:55] [6] [irc/freenode] 3:#test(+n){24}        │
+└──────────────────────────────────────────────────┘
+        filling_left_right = columns_vertical ▲
+
+┌───────────────────────────────────────────────────────────────────────┐
+│@carl    %Diego    celia    Harold^  jodie    mario    Rachel   Vince  │
+│@jessika %Melody   Eva      henry4   lee      mark     richard  warren │
+│@maddy   +Max      freddy   jimmy17  louise   peter    sheryl   zack   │
+│───────────────────────────────────────────────────────────────────────│
+│                                                                       │
+        filling_top_bottom = columns_vertical ▲
+
+┌───────────────────────────────────────────────────────────────────────┐
+│@carl    @jessika @maddy   %Diego   %Melody  +Max      celia    Eva    │
+│ freddy   Harold^  henry4   jimmy17  jodie    lee      louise   mario  │
+│ mark     peter    Rachel   richard  sheryl   Vince    warren   zack   │
+│───────────────────────────────────────────────────────────────────────│
+│                                                                       │
+      filling_top_bottom = columns_horizontal ▲
+........................................
+
+[[bar_conditions]]
+Conditions
+^^^^^^^^^^
+
+The option 'conditions' is a string evaluated to know if the bar is displayed
+or not in the window (it is used only for bars with type 'window').
+
+The string can be:
+
+* 'active': the window must be active
+* 'inactive': the window must be inactive
+* 'nicklist': the buffer displayed in window must have a nicklist
+* an expression: it is evaluated as boolean (see command
+  <<command_weechat_eval,/eval>>)
+
+For the expression, following variables are available:
+
+* `${active}`: true if window is active
+* `${inactive}`: true if window is inactive
+* `$[nicklist}`: true if buffer displayed in window has a nicklist
+
+Following pointers are available:
+
+* `${window}`: the window where condition is evaluated
+* `${buffer}`: the buffer of window where condition is evaluated
+
+Exemple to display nicklist bar in all buffers with a nicklist, and only if
+width of window is > 100 :
+
+----------------------------------------
+/set weechat.bar.nicklist.conditions "${nicklist} && ${window.win_width} > 100"
+----------------------------------------
+
+Same condition, but always display nicklist on buffer '&bitlbee' (even if window
+is small):
+
+----------------------------------------
+/set weechat.bar.nicklist.conditions "${nicklist} && (${window.win_width} > 100 || ${buffer.full_name} == irc.bitlbee.&bitlbee)"
+----------------------------------------
+
 [[notify_levels]]
 Benachrichtigungsstufen
 ~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/doc/en/autogen/plugin_api/hdata.txt b/doc/en/autogen/plugin_api/hdata.txt
index aa379c246..464880912 100644
--- a/doc/en/autogen/plugin_api/hdata.txt
+++ b/doc/en/autogen/plugin_api/hdata.txt
@@ -325,8 +325,6 @@
 | weechat | bar | bar |
   'name' (string) +
   'options' (pointer) +
-  'conditions_count' (integer) +
-  'conditions_array' (string, array_size: "conditions_count") +
   'items_count' (integer) +
   'items_subcount' (pointer) +
   'items_array' (pointer) +
diff --git a/doc/en/autogen/user/weechat_commands.txt b/doc/en/autogen/user/weechat_commands.txt
index 17eeb9b6f..7438d2805 100644
--- a/doc/en/autogen/user/weechat_commands.txt
+++ b/doc/en/autogen/user/weechat_commands.txt
@@ -11,7 +11,7 @@ message: message for away (if no message is given, away status is removed)
 [command]*`bar`* manage bars::
 ........................................
 /bar  list|listfull|listitems
-      add <name> <type>[,<cond1>[,<cond2>...]] <position> <size> <separator> <item1>[,<item2>...]
+      add <name> <type>[,<condition>] <position> <size> <separator> <item1>[,<item2>...]
       default [input|title|status|nicklist]
       del <name>|-all
       set <name> <option> <value>
@@ -25,11 +25,12 @@ message: message for away (if no message is given, away status is removed)
          name: name of bar (must be unique)
          type:   root: outside windows,
                window: inside windows, with optional conditions (see below)
-    cond1,...: condition(s) for displaying bar (only for type "window"):
+    condition: condition(s) for displaying bar (only for type "window"):
                  active: on active window
                inactive: on inactive windows
                nicklist: on windows with nicklist
-               without condition, bar is always displayed
+               other condition: see /help weechat.bar.xxx.conditions and /help eval
+               without condition, the bar is always displayed
      position: bottom, top, left or right
          size: size of bar (in chars)
     separator: 1 for using separator (line), 0 or nothing means no separator
@@ -199,6 +200,60 @@ infolists: display infos about infolists
   windows: display windows tree
 ........................................
 
+[[command_weechat_eval]]
+[command]*`eval`* evaluate expression and send result to buffer::
+........................................
+/eval  [-n] <expression>
+       [-n] <expression1> <operator> <expression2>
+
+        -n: display result without sending it to buffer (debug mode)
+expression: expression to evaluate, variables with format ${variable} are replaced (see below)
+  operator: a logical or comparison operator:
+            - logical operators:
+                &&  boolean "and"
+                ||  boolean "or"
+            - comparison operators:
+                ==  equal
+                !=  not equal
+                <=  less or equal
+                <   less
+                >=  greater or equal
+                >   greater
+                =~  is matching regex
+                !~  is NOT matching regex
+
+An expression is considered as "true" if it is not NULL, not empty, and different from "0".
+The comparison is made using integers if the two expressions are valid integers.
+To force a string comparison, add double quotes around each expression, for example:
+  50 > 100      ==> 0
+  "50" > "100"  ==> 1
+
+Some variables are replaced in expression, using the format ${variable}, variable can be, by order of prioity :
+  1. the name of an option (file.section.option)
+  2. a hdata name/variable (the value is automatically converted to string), by default "window" and "buffer" point to current window/buffer.
+Format for hdata can be one of following:
+  hdata.var1.var2...: start with a hdata (pointer must be known), and ask variables one after one (other hdata can be followed)
+  hdata(list).var1.var2...: start with a hdata using a list, for example:
+    ${buffer[gui_buffers].full_name}: full name of first buffer in linked list of buffers
+    ${plugin[weechat_plugins].name}: name of first plugin in linked list of plugins
+For name of hdata and variables, please look at "Plugin API reference", function "weechat_hdata_get".
+
+Examples:
+  /eval -n ${weechat.look.scroll_amount}  ==> 3
+  /eval -n ${window}                      ==> 0x2549aa0
+  /eval -n ${window.buffer}               ==> 0x2549320
+  /eval -n ${window.buffer.full_name}     ==> core.weechat
+  /eval -n ${window.buffer.number}        ==> 1
+  /eval -n ${window.buffer.number} > 2    ==> 0
+  /eval -n ${window.win_width} > 100      ==> 1
+  /eval -n (8 > 12) || (5 > 2)            ==> 1
+  /eval -n (8 > 12) && (5 > 2)            ==> 0
+  /eval -n abcd =~ ^ABC                   ==> 1
+  /eval -n abcd =~ (?-i)^ABC              ==> 0
+  /eval -n abcd =~ (?-i)^abc              ==> 1
+  /eval -n abcd !~ abc                    ==> 0
+........................................
+
 [[command_weechat_filter]]
 [command]*`filter`* filter messages in buffers, to hide/show them according to tags or regex::
 ........................................
diff --git a/doc/en/weechat_dev.en.txt b/doc/en/weechat_dev.en.txt
index d706e23c0..32efb14e9 100644
--- a/doc/en/weechat_dev.en.txt
+++ b/doc/en/weechat_dev.en.txt
@@ -99,6 +99,7 @@ WeeChat "core" reside in following directories:
 |    wee-config-file.c          | Configuration file management
 |    wee-config.c               | Configuration options for WeeChat core (options weechat.*)
 |    wee-debug.c                | Some debug functions
+|    wee-eval.c                 | Evaluate expressions with references to internal vars
 |    wee-hashtable.c            | Hashtables
 |    wee-hdata.c                | Hdata (direct access to data using hashtables)
 |    wee-hook.c                 | Hooks
diff --git a/doc/en/weechat_plugin_api.en.txt b/doc/en/weechat_plugin_api.en.txt
index b4784dfa8..5b4b913f7 100644
--- a/doc/en/weechat_plugin_api.en.txt
+++ b/doc/en/weechat_plugin_api.en.txt
@@ -1654,6 +1654,59 @@ str2 = weechat.string_input_for_buffer("/test")  # ""
 str3 = weechat.string_input_for_buffer("//test") # "/test"
 ----------------------------------------
 
+weechat_string_eval_expression
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+_New in version 0.4.0._
+
+Evaluate an expression and return result as a string.
+Special variables with format `${variable}` are expanded (see command `/eval` in
+'WeeChat User's guide').
+
+Prototype:
+
+[source,C]
+----------------------------------------
+char *weechat_string_eval_expression (const char *expr,
+                                      struct t_hashtable *pointers,
+                                      struct t_hashtable *extra_vars);
+----------------------------------------
+
+Arguments:
+
+* 'expr': the expression to evaluate
+* 'pointers': hashtable with pointers (keys must be string, values must be
+  pointer); pointers "window" and "buffer" are automatically added if they are
+  not in hashtable (with pointer to current window/buffer) (can be NULL)
+* 'extra_vars': extra variables that will be expanded (can be NULL)
+
+Return value:
+
+* evaluated expression (must be freed by calling "free" after use), or NULL
+  if problem (invalid expression or not enough memory)
+
+C examples:
+
+[source,C]
+----------------------------------------
+char *str1 = weechat_string_eval_expression ("${buffer.full_name}", NULL, NULL);       /* "core.weechat" */
+char *str2 = weechat_string_eval_expression ("${window.win_width} > 100", NULL, NULL); /* "1" */
+char *str3 = weechat_string_eval_expression ("abc =~ def", NULL, NULL);                /* "0" */
+----------------------------------------
+
+Script (Python):
+
+[source,python]
+----------------------------------------
+# prototype
+str = weechat.string_eval_expression(expr, pointers, extra_vars)
+
+# examples
+str1 = weechat.string_input_for_buffer("${buffer.full_name}", {}, {})       # "core.weechat"
+str2 = weechat.string_input_for_buffer("${window.win_width} > 100", {}, {}) # "1"
+str3 = weechat.string_input_for_buffer("abc =~ def", {}, {})                # "0"
+----------------------------------------
+
 [[utf-8]]
 UTF-8
 ~~~~~
diff --git a/doc/en/weechat_user.en.txt b/doc/en/weechat_user.en.txt
index 5f021b90f..0d2514bd4 100644
--- a/doc/en/weechat_user.en.txt
+++ b/doc/en/weechat_user.en.txt
@@ -554,6 +554,218 @@ Example of vertical + horizontal splits:
                   (buffer #3)
 ........................................
 
+[[bars]]
+Bars
+~~~~
+
+A 'bar' is an area beside the chat that can contain any type of text.
+
+The bar options can be set with options `weechat.bar.name.option` where `name`
+is the name of the bar and `option` the option for this bar.
+
+List of bar options:
+
+[width="100%",cols="2m,2,10",options="header"]
+|========================================
+| Option | Values | Description
+
+| type | `root`, `window` |
+  A bar with type `root` is displayed exactly one time on screen, outside all
+  windows. There is no root bar by default, but an example is the bar 'buffers'
+  created by script 'buffers.pl' (sidebar with list of buffers). +
+  A bar with type `window` is displayed in each window, for example if you
+  split one time the screen (with `/window splith` or `/window splitv`), you
+  will have one bar in each window. The four default bars ('title', 'status',
+  'input', 'nicklist') have type `window`.
+
+| position | `top`, `bottom`, `left`, `right` |
+  Position of the bar: above/below chat, on the left/right.
+
+| priority | integer ≥ 0 |
+  Priority for display of bar: this is used for ordering the bars on screen when
+  many bars have same type and position. +
+  The bars are displayed from the edge of the screen to the center. A higher
+  priority will display bar at the beginning, so closer to the edge. +
+  Example: 'input' bar has priority 1000, so it is displayed before the 'status'
+  bar, which has priority 500.
+
+| size | integer ≥ 0 |
+  The size of the bar: number of columns for position left/right, number
+  of lines for position top/tobbom. A size of `0` means automatic, so the size
+  will be computed according to content displayed in bar.
+
+| size_max | integer ≥ 0 |
+  The maximum size for a bar, `0` = no limit (this option is used only if
+  `size` = `0`).
+
+| color_bg | color |
+  The default background color for the bar.
+
+| color_fg | color |
+  The default text color for the bar.
+
+| color_delim | color |
+  The color for delimiters in bar.
+
+| hidden | `on`, `off` |
+  When option is `on`, the bar is hidden. +
+  Note: instead of changing this option, the command `/bar` is preferred, for
+  example: `/bar toggle nicklist` (see command <<command_weechat_bar,/bar>>).
+
+| separator | `on`, `off` |
+  When option is `on`, a separator (line) is displayed between this bar and
+  other bars (or chat).
+
+| items | string |
+  A list of 'items' (see <<bar_items,items>> for more info).
+
+| filling_left_right | `horizontal`, `vertical`, `columns_horizontal`, `columns_vertical` |
+  Type of filling for a bar which has position `left` or `right` (see
+  <<bar_filling,filling>> for more info).
+
+| filling_top_bottom | `horizontal`, `vertical`, `columns_horizontal`, `columns_vertical` |
+  Type of filling for a bar which has position `top` or `bottom` (see
+  <<bar_filling,filling>> for more info).
+
+| conditions | string |
+  The conditions to display the bar (see <<bar_conditions,conditions>> for more
+  info).
+|========================================
+
+[[bar_items]]
+Items
+^^^^^
+
+The option 'items' is a string with a list of bar items, separated by a comma
+(space between items on screen) or "+" (glued items).
+
+The list of bar items is displayed with command `/bar listitems`.
+
+Example of bar with items "[time],buffer_number+:+buffer_plugin+.+buffer_name":
+
+........................................
+┌─────────────────────────────────────────────────────────────────────────────────────────┐
+│[12:55] 3:irc/freenode.#weechat                                                          │
+└─────────────────────────────────────────────────────────────────────────────────────────┘
+........................................
+
+[[bar_filling]]
+Filling
+^^^^^^^
+
+There are four types of filling:
+
+* `horizontal`: the items are displayed horizontally, from left to right. If
+  there are new lines in items, a space is used to separate lines.
+* `vertical`: the items are displayed from top to bottom. If there are new
+  lines in items, a new line is used to separate lines.
+* `columns_horizontal`: items are displayed using columns, where text is
+  aligned on the left. The first item is on top left, the second is on same
+  line, on the right.
+* `columns_vertical`: items are displayed using columns, where text is aligned
+  on the left. The first item is on top left, the second is one line below.
+
+Default bars 'title', 'status' and 'input' have 'horizontal' filling, and
+default bar 'nicklist' has 'vertical' filling.
+
+Some examples of filling for bar 'nicklist':
+
+........................................
+┌──────────────────────────────────────────────────┐
+│Welcome to #test, this is a test channel          │
+│12:54:15 peter | hey!                    │@carl   │
+│12:55:01  +Max | hello                   │@jessika│
+│                                         │@maddy  │
+│                                         │%Diego  │
+│                                         │%Melody │
+│                                         │+Max    │
+│                                         │ celia  │
+│                                         │ Eva    │
+│                                         │ freddy │
+│                                         │ Harold^│
+│                                         │ henry4 │
+│                                         │ jimmy17│
+│                                         │ jodie ▼│
+│[12:55] [6] [irc/freenode] 3:#test(+n){24}        │
+└──────────────────────────────────────────────────┘
+                filling_left_right = vertical ▲
+
+┌──────────────────────────────────────────────────┐
+│Welcome to #test, this is a test channel          │
+│12:54:15 peter | hey!           │@carl     lee    │
+│12:55:01  +Max | hello          │@jessika  louise │
+│                                │@maddy    mario  │
+│                                │%Diego    mark   │
+│                                │%Melody   peter  │
+│                                │+Max      Rachel │
+│                                │ celia    richard│
+│                                │ Eva      sheryl │
+│                                │ freddy   Vince  │
+│                                │ Harold^  warren │
+│                                │ henry4   zack   │
+│                                │ jimmy17         │
+│                                │ jodie           │
+│[12:55] [6] [irc/freenode] 3:#test(+n){24}        │
+└──────────────────────────────────────────────────┘
+        filling_left_right = columns_vertical ▲
+
+┌───────────────────────────────────────────────────────────────────────┐
+│@carl    %Diego    celia    Harold^  jodie    mario    Rachel   Vince  │
+│@jessika %Melody   Eva      henry4   lee      mark     richard  warren │
+│@maddy   +Max      freddy   jimmy17  louise   peter    sheryl   zack   │
+│───────────────────────────────────────────────────────────────────────│
+│                                                                       │
+        filling_top_bottom = columns_vertical ▲
+
+┌───────────────────────────────────────────────────────────────────────┐
+│@carl    @jessika @maddy   %Diego   %Melody  +Max      celia    Eva    │
+│ freddy   Harold^  henry4   jimmy17  jodie    lee      louise   mario  │
+│ mark     peter    Rachel   richard  sheryl   Vince    warren   zack   │
+│───────────────────────────────────────────────────────────────────────│
+│                                                                       │
+      filling_top_bottom = columns_horizontal ▲
+........................................
+
+[[bar_conditions]]
+Conditions
+^^^^^^^^^^
+
+The option 'conditions' is a string evaluated to know if the bar is displayed
+or not in the window (it is used only for bars with type 'window').
+
+The string can be:
+
+* 'active': the window must be active
+* 'inactive': the window must be inactive
+* 'nicklist': the buffer displayed in window must have a nicklist
+* an expression: it is evaluated as boolean (see command
+  <<command_weechat_eval,/eval>>)
+
+For the expression, following variables are available:
+
+* `${active}`: true if window is active
+* `${inactive}`: true if window is inactive
+* `$[nicklist}`: true if buffer displayed in window has a nicklist
+
+Following pointers are available:
+
+* `${window}`: the window where condition is evaluated
+* `${buffer}`: the buffer of window where condition is evaluated
+
+Exemple to display nicklist bar in all buffers with a nicklist, and only if
+width of window is > 100 :
+
+----------------------------------------
+/set weechat.bar.nicklist.conditions "${nicklist} && ${window.win_width} > 100"
+----------------------------------------
+
+Same condition, but always display nicklist on buffer '&bitlbee' (even if window
+is small):
+
+----------------------------------------
+/set weechat.bar.nicklist.conditions "${nicklist} && (${window.win_width} > 100 || ${buffer.full_name} == irc.bitlbee.&bitlbee)"
+----------------------------------------
+
 [[notify_levels]]
 Notify levels
 ~~~~~~~~~~~~~
diff --git a/doc/fr/autogen/plugin_api/hdata.txt b/doc/fr/autogen/plugin_api/hdata.txt
index 7ed0a160b..16ca00f49 100644
--- a/doc/fr/autogen/plugin_api/hdata.txt
+++ b/doc/fr/autogen/plugin_api/hdata.txt
@@ -325,8 +325,6 @@
 | weechat | bar | barre |
   'name' (string) +
   'options' (pointer) +
-  'conditions_count' (integer) +
-  'conditions_array' (string, array_size: "conditions_count") +
   'items_count' (integer) +
   'items_subcount' (pointer) +
   'items_array' (pointer) +
diff --git a/doc/fr/autogen/user/weechat_commands.txt b/doc/fr/autogen/user/weechat_commands.txt
index b98bc1725..9af2d263b 100644
--- a/doc/fr/autogen/user/weechat_commands.txt
+++ b/doc/fr/autogen/user/weechat_commands.txt
@@ -11,7 +11,7 @@ message: message pour l'absence (si pas de message donné, le statut d'absence e
 [command]*`bar`* gestion des barres::
 ........................................
 /bar  list|listfull|listitems
-      add <nom> <type>[,<cond1>[,<cond2>...]] <position> <taille> <séparateur> <objet1>[,<objet2>...]
+      add <nom> <type>[,<conditions>] <position> <taille> <séparateur> <objet1>[,<objet2>...]
       default [input|title|status|nicklist]
       del <nom>|-all
       set <nom> <option> <valeur>
@@ -25,10 +25,11 @@ message: message pour l'absence (si pas de message donné, le statut d'absence e
           nom: nom de la barre (doit être unique)
          type:   root: en dehors des fenêtres
                window: dans les fenêtres, avec condition(s) optionnelle(s) (voir ci-dessous)
-    cond1,...: condition(s) pour afficher cette barre (seulement pour le type "window"):
+    condition: condition(s) pour afficher cette barre (seulement pour le type "window"):
                  active: sur la fenêtre active
                inactive: sur les fenêtres inactives
                nicklist: sur les fenêtres avec liste de pseudos
+               autre condition: voir /help weechat.bar.xxx.conditions et /help eval
                sans condition, la barre est toujours affichée
      position: bottom (bas), top (haut), left (gauche) ou right (droite)
        taille: taille de la barre (en caractères)
@@ -199,6 +200,60 @@ infolists: afficher des infos sur les infolists
   windows: afficher l'arbre des fenêtres
 ........................................
 
+[[command_weechat_eval]]
+[command]*`eval`* évaluer une expression et envoyer le résultat au tampon::
+........................................
+/eval  [-n] <expression>
+       [-n] <expression1> <opérateur> <expression2>
+
+        -n: afficher le résultat sans envoyer au tampon (mode debug)
+expression: expression à évaluer, les variables avec le format ${variable} sont remplacées (voir ci-dessous)
+ opérateur: un opérateur logique ou de comparaison :
+            - opérateurs logiques :
+                &&  "et" booléen
+                ||  "ou" booléen
+            - opérateurs de comparaison :
+                ==  égal
+                !=  non égal
+                <=  inférieur ou égal
+                <   inférieur
+                >=  supérieur ou égal
+                >   supérieur
+                =~  correspond à l'expression régulière
+                !~  ne correspond PAS à l'expression régulière
+
+Une expression est considérée comme "vraie" si elle est non NULL, non vide, et différente de "0".
+La comparaison est faite en utilisant des entiers si les deux expressions sont des entiers valides.
+Pour forcer une comparaison de chaînes, ajoutez des guillemets autour de chaque expression, par exemple :
+  50 > 100      ==> 0
+  "50" > "100"  ==> 1
+
+Des variables sont remplacées dans l'expression, en utilisant le format ${variable}, la variable pouvant être, par ordre de priorité :
+  1. le nom d'une option (fichier.section.option)
+  2. le nom d'un hdata/variable (la valeur est automatiquement convertie en chaîne), par défaut "window" et "buffer" pointent vers la fenêtre et le tampon courants.
+Le format du hdata peut être le suivant :
+  hdata.var1.var2...: démarrer avec un hdata (le pointeur doit être connu), et demander les variables l'une après l'autre (d'autres hdata peuvent être suivis)
+  hdata(list).var1.var2...: démarrer avec un hdata en utlisant une liste, par exemple :
+    ${buffer[gui_buffers].full_name}: nom complet du premier tampon dans la liste chaînée des tampons
+    ${plugin[weechat_plugins].name}: nom de la première extension dans la liste chaînée des extensions
+Pour le nom du hdata et des variables, voir la "Référence API extension", fonction "weechat_hdata_get".
+
+Exemples:
+  /eval -n ${weechat.look.scroll_amount}  ==> 3
+  /eval -n ${window}                      ==> 0x2549aa0
+  /eval -n ${window.buffer}               ==> 0x2549320
+  /eval -n ${window.buffer.full_name}     ==> core.weechat
+  /eval -n ${window.buffer.number}        ==> 1
+  /eval -n ${window.buffer.number} > 2    ==> 0
+  /eval -n ${window.win_width} > 100      ==> 1
+  /eval -n (8 > 12) || (5 > 2)            ==> 1
+  /eval -n (8 > 12) && (5 > 2)            ==> 0
+  /eval -n abcd =~ ^ABC                   ==> 1
+  /eval -n abcd =~ (?-i)^ABC              ==> 0
+  /eval -n abcd =~ (?-i)^abc              ==> 1
+  /eval -n abcd !~ abc                    ==> 0
+........................................
+
 [[command_weechat_filter]]
 [command]*`filter`* filtrer les messages dans les tampons, pour les cacher/afficher selon des tags ou expressions régulières::
 ........................................
diff --git a/doc/fr/weechat_plugin_api.fr.txt b/doc/fr/weechat_plugin_api.fr.txt
index c042dc0ae..d6348e0b4 100644
--- a/doc/fr/weechat_plugin_api.fr.txt
+++ b/doc/fr/weechat_plugin_api.fr.txt
@@ -1677,6 +1677,61 @@ str2 = weechat.string_input_for_buffer("/test")  # ""
 str3 = weechat.string_input_for_buffer("//test") # "/test"
 ----------------------------------------
 
+weechat_string_eval_expression
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+_Nouveau dans la version 0.4.0._
+
+Evalue l'expression et retourne le résultat sous forme de chaîne.
+Les variables spéciales avec le format `${variable}` sont étendues (voir la
+commande `/eval` dans le 'Guide utilisateur WeeChat').
+
+Prototype :
+
+[source,C]
+----------------------------------------
+char *weechat_string_eval_expression (const char *expr,
+                                      struct t_hashtable *pointers,
+                                      struct t_hashtable *extra_vars);
+----------------------------------------
+
+Paramètres :
+
+* 'expr' : l'expression à évaluer
+* 'pointers' : hashtable avec les pointeurs (les clés doivent être des chaînes,
+  les valeurs doivent être des pointeurs); les pointeurs "window" et "buffer"
+  sont automatiquement ajoutés s'ils ne sont pas dans la hashtable (avec le
+  pointer vers fenêtre/tampon courants) (peut être NULL)
+* 'extra_vars' : variables additionnelles qui seront étendues (peut être NULL)
+
+Valeur de retour :
+
+* expression évaluée (doit être libérée après un appel à "free" après
+  utilisation), ou NULL si problème (expression invalide ou pas assez de
+  mémoire)
+
+Exemples en C :
+
+[source,C]
+----------------------------------------
+char *str1 = weechat_string_eval_expression ("${buffer.full_name}", NULL, NULL);       /* "core.weechat" */
+char *str2 = weechat_string_eval_expression ("${window.win_width} > 100", NULL, NULL); /* "1" */
+char *str3 = weechat_string_eval_expression ("abc =~ def", NULL, NULL);                /* "0" */
+----------------------------------------
+
+Script (Python) :
+
+[source,python]
+----------------------------------------
+# prototype
+str = weechat.string_eval_expression(expr, pointers, extra_vars)
+
+# exemples
+str1 = weechat.string_input_for_buffer("${buffer.full_name}", {}, {})       # "core.weechat"
+str2 = weechat.string_input_for_buffer("${window.win_width} > 100", {}, {}) # "1"
+str3 = weechat.string_input_for_buffer("abc =~ def", {}, {})                # "0"
+----------------------------------------
+
 [[utf-8]]
 UTF-8
 ~~~~~
diff --git a/doc/fr/weechat_user.fr.txt b/doc/fr/weechat_user.fr.txt
index ba4b27ce8..7db404f4f 100644
--- a/doc/fr/weechat_user.fr.txt
+++ b/doc/fr/weechat_user.fr.txt
@@ -565,6 +565,229 @@ Exemple de découpage vertical + horizontal :
                   (tampon n°3)
 ........................................
 
+[[bars]]
+Barres
+~~~~~~
+
+Une 'barre' est une zone à côté de la discussion qui peut contenir tout type de
+texte.
+
+Les options de barre sont définies avec les options `weechat.bar.nom.option` où
+`nom` et le nom de la barre et `option` l'option pour cette barre.
+
+Liste des options de barre :
+
+[width="100%",cols="2m,2,10",options="header"]
+|========================================
+| Option | Valeurs | Description
+
+| type | `root`, `window` |
+  Une barre avec le type `root` est affichée exactement une fois à l'écran, en
+  dehors de toutes les fenêtres. Il n'y a pas de barre root par défaut, mais un
+  exemple est la barre 'buffers' créée par le script 'buffers.pl' (barre
+  latérale avec la liste des tampons). +
+  Une barre avec le type `window` est affichée dans chaque fenêtre, par exemple
+  si vous découpez l'écran (avec `/window splith` ou `/window splitv`), vous
+  aurez une barre dans chaque fenêtre. Les quatre barres par défaut ('title',
+  'status', 'input', 'nicklist') sont de type `window`.
+
+| position | `top`, `bottom`, `left`, `right` |
+  Position de la barre : au dessus/en dessous de la discussion, sur la
+  gauche/droite.
+
+| priority | entier ≥ 0 |
+  Priorité de la barre : elle est utilisée pour ordonner les barres à l'écran,
+  quand plusieurs barres utilisent le même type et position. +
+  Les barres sont affichées depuis le bord de l'écran vers le centre. Une
+  priorité plus haute affichera la barre au début, donc près du bord. +
+  Exemple : la barre 'input' a une priorité de 1000, donc elle est affichée
+  avant la barre 'status', qui a une priorité de 500.
+
+| size | entier ≥ 0 |
+  La taille de la barre : nombre de colonnes pour une position left/right,
+  nombre de lignes pour une position top/bottom. Une taille de `0` signifie
+  automatique, donc la taille sera calculée en fonction du contenu affiché dans
+  la barre.
+
+| size_max | entier ≥ 0 |
+  La taille maximum pour la barre, `0` = pas de limite (cette option est
+  utilisée seulement si `size` = `0`).
+
+| color_bg | couleur |
+  La couleur par défaut du fond de la barre.
+
+| color_fg | couleur |
+  La couleur par défaut du texte dans la barre.
+
+| color_delim | couleur |
+  La couleur des délimiteurs dans la barre.
+
+| hidden | `on`, `off` |
+  Lorsque l'option est `on`, la barre est cachée. +
+  Note : plutôt que de changer cette option, il est préférable d'utiliser la
+  commande `/bar`, par exemple : `/bar toggle nicklist` (voir la commande
+  <<command_weechat_bar,/bar>>).
+
+| separator | `on`, `off` |
+  Lorsque l'option est `on`, un séparateur (ligne) est affiché entre la barre et
+  les autres barres (ou la discussion).
+
+| items | chaîne |
+  Une liste d'objets (voir <<bar_items,objets>> pour plus d'infos).
+
+| filling_left_right | `horizontal`, `vertical`, `columns_horizontal`, `columns_vertical` |
+  Type de remplissage pour la barre lorsqu'elle a une position `left` ou
+  `right` (voir <<bar_filling,remplissage>> pour plus d'infos).
+
+| filling_top_bottom | `horizontal`, `vertical`, `columns_horizontal`, `columns_vertical` |
+  Type de remplissage pour la barre lorsqu'elle a une position `top` ou `bottom`
+  (voir <<bar_filling,remplissage>> pour plus d'infos).
+
+| conditions | chaîne |
+  Les conditions pour afficher la barre (voir <<bar_conditions,conditions>> pour
+  plus d'infos).
+|========================================
+
+[[bar_items]]
+Objets
+^^^^^^
+
+L'option 'items' est une chaîne avec une liste d'objets de barre, séparés par
+une virgule (espace entre les objets à l'écran) ou un "+" (objets collés).
+
+La liste des objets de barre est affichée avec la commande `/bar listitems`.
+
+Exemple de barre avec les objets
+"[time],buffer_number+:+buffer_plugin+.+buffer_name" :
+
+........................................
+┌─────────────────────────────────────────────────────────────────────────────────────────┐
+│[12:55] 3:irc/freenode.#weechat                                                          │
+└─────────────────────────────────────────────────────────────────────────────────────────┘
+........................................
+
+[[bar_filling]]
+Remplissage
+^^^^^^^^^^^
+
+Il y a quatre types de remplissage :
+
+* `horizontal` : les objets sont affichés horizontalement, de gauche à droite.
+  S'il y a des retours à la ligne dans les objets, un espace est utilisé pour
+  séparer les lignes.
+* `vertical` : les objets sont affichés de haut en bas. S'il y a des retours à
+  la ligne dans les objets, une nouvelle ligne est utilisée pour séparer les
+  lignes.
+* `columns_horizontal` : les objets sont affichés en utilisant des colonnes, où
+  le texte est aligné à gauche. Le premier objet est en haut à gauche, le second
+  est sur la même ligne, sur la droite.
+* `columns_vertical` : les objets sont affichés en utilisant des colonnes, où
+  le texte est aligné à gauche. Le premier objet est en haut à gauche, le second
+  est sur la ligne en dessous.
+
+Les barres par défaut 'title', 'status' et 'input' ont un remplissage
+'horizontal', et la barre par défaut 'nicklist' a un remplissage 'vertical'.
+
+Quelques exemples de remplissage pour la barre 'nicklist' :
+
+........................................
+┌──────────────────────────────────────────────────┐
+│Welcome to #test, this is a test channel          │
+│12:54:15 peter | hey!                    │@carl   │
+│12:55:01  +Max | hello                   │@jessika│
+│                                         │@maddy  │
+│                                         │%Diego  │
+│                                         │%Melody │
+│                                         │+Max    │
+│                                         │ celia  │
+│                                         │ Eva    │
+│                                         │ freddy │
+│                                         │ Harold^│
+│                                         │ henry4 │
+│                                         │ jimmy17│
+│                                         │ jodie ▼│
+│[12:55] [6] [irc/freenode] 3:#test(+n){24}        │
+└──────────────────────────────────────────────────┘
+                filling_left_right = vertical ▲
+
+┌──────────────────────────────────────────────────┐
+│Welcome to #test, this is a test channel          │
+│12:54:15 peter | hey!           │@carl     lee    │
+│12:55:01  +Max | hello          │@jessika  louise │
+│                                │@maddy    mario  │
+│                                │%Diego    mark   │
+│                                │%Melody   peter  │
+│                                │+Max      Rachel │
+│                                │ celia    richard│
+│                                │ Eva      sheryl │
+│                                │ freddy   Vince  │
+│                                │ Harold^  warren │
+│                                │ henry4   zack   │
+│                                │ jimmy17         │
+│                                │ jodie           │
+│[12:55] [6] [irc/freenode] 3:#test(+n){24}        │
+└──────────────────────────────────────────────────┘
+        filling_left_right = columns_vertical ▲
+
+┌───────────────────────────────────────────────────────────────────────┐
+│@carl    %Diego    celia    Harold^  jodie    mario    Rachel   Vince  │
+│@jessika %Melody   Eva      henry4   lee      mark     richard  warren │
+│@maddy   +Max      freddy   jimmy17  louise   peter    sheryl   zack   │
+│───────────────────────────────────────────────────────────────────────│
+│                                                                       │
+        filling_top_bottom = columns_vertical ▲
+
+┌───────────────────────────────────────────────────────────────────────┐
+│@carl    @jessika @maddy   %Diego   %Melody  +Max      celia    Eva    │
+│ freddy   Harold^  henry4   jimmy17  jodie    lee      louise   mario  │
+│ mark     peter    Rachel   richard  sheryl   Vince    warren   zack   │
+│───────────────────────────────────────────────────────────────────────│
+│                                                                       │
+      filling_top_bottom = columns_horizontal ▲
+........................................
+
+[[bar_conditions]]
+Conditions
+^^^^^^^^^^
+
+L'option 'conditions' est uen chaîne évaluée pour savoir si la barre doit être
+affichée ou non dans la fenêtre (elle est utilisée seulement pour les barres
+avec type 'window').
+
+La chaîne peut être :
+
+* 'active' : la fenêtre doit être active
+* 'inactive' : la fenêtre doit être inactive
+* 'nicklist' : le tampon affiché dans la fenêtre doit avoir une liste de pseudos
+* une expression : elle est évaluée comme booléen (voir la commande
+  <<command_weechat_eval,/eval>>)
+
+Pour une expression, les variables suivantes sont disponibles :
+
+* `${active}` : vrai si la fenêtre est active
+* `${inactive}` : vrai si la fenêtre est inactive
+* `$[nicklist}` : vrai si le tampon affiché dans la fenêtre a une liste de
+  pseudos
+
+Les pointeurs suivants sont disponibles :
+
+* `${window}` : la fenêtre où la condition est évaluée
+* `${buffer}` : le tampon de la fenêtre où la condition est évaluée
+
+Exemple pour afficher la liste de pseudos dans tous les tampons possédant une
+liste de pseudos, et seulement si la largeur de fenêtre est supérieurs à 100 :
+
+----------------------------------------
+/set weechat.bar.nicklist.conditions "${nicklist} && ${window.win_width} > 100"
+----------------------------------------
+
+Même condition, mais affichier toujours la liste de pseudos sur le tampon
+'&bitlbee' (même si la fenêtre est petite) :
+
+----------------------------------------
+/set weechat.bar.nicklist.conditions "${nicklist} && (${window.win_width} > 100 || ${buffer.full_name} == irc.bitlbee.&bitlbee)"
+----------------------------------------
+
 [[notify_levels]]
 Niveaux de notification
 ~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/doc/it/autogen/plugin_api/hdata.txt b/doc/it/autogen/plugin_api/hdata.txt
index b6eea6f14..6fac22ed9 100644
--- a/doc/it/autogen/plugin_api/hdata.txt
+++ b/doc/it/autogen/plugin_api/hdata.txt
@@ -325,8 +325,6 @@
 | weechat | bar | barra |
   'name' (string) +
   'options' (pointer) +
-  'conditions_count' (integer) +
-  'conditions_array' (string, array_size: "conditions_count") +
   'items_count' (integer) +
   'items_subcount' (pointer) +
   'items_array' (pointer) +
diff --git a/doc/it/autogen/user/weechat_commands.txt b/doc/it/autogen/user/weechat_commands.txt
index 2508775bf..ba77936b3 100644
--- a/doc/it/autogen/user/weechat_commands.txt
+++ b/doc/it/autogen/user/weechat_commands.txt
@@ -11,49 +11,50 @@ messaggio: messaggio di assenza (se non specificato, lo stato di assenza viene r
 [command]*`bar`* gestione delle barre::
 ........................................
 /bar  list|listfull|listitems
-      add <nome> <tipo>[,<cond1>[,<cond2>...]] <posizione> <dimensione> <separatore> <item1>[,<item2>...]
+      add <name> <type>[,<condition>] <position> <size> <separator> <item1>[,<item2>...]
       default [input|title|status|nicklist]
-      del <nome>|-all
-      set <nome> <opzione> <valore>
-      hide|show|toggle <nome>
-      scroll <nome> <finestra> <scroll_value>
+      del <name>|-all
+      set <name> <option> <value>
+      hide|show|toggle <name>
+      scroll <name> <window> <scroll_value>
 
-         list: elenca tutte le barre
-     listfull: elenca tutte le barre (dettagliato)
-    listitems: elenca tutti gli elementi della barra
-          add: aggiunge una nuova barra
-         nome: nome della barra (deve essere unico)
-         tipo:   root: al di fuori delle finestre,
-               window: all'interno delle finestre, con opzioni condizionali (a seguire)
-    cond1,...: condizione(i) per visualizzare la barra (solo per il tipo "window"):
-                 active: sulla finestra attiva
-               inactive: sulle finestre inattive
-               nicklist: sulle finestre con la lista nick
-               senza condizione, viene sempre mostrata
-    posizione: bottom (basso), top (alto), left (sinistra) o right (destra)
-   dimensione: dimensione della barra (in caratteri)
-   separatore: 1 per usarlo (riga), 0 o nulla equivale a nessun separatore
-    item1,...: elementi per questa barra (possono essere separati da virgole (spazio tra gli elementi) o "+" (elementi incollati))
-      default: crea una barra predefinita (saranno tutte predefinite se non viene dato un nome per la barra)
-          del: elimina una barra (o tutte le barre con -all)
-          set: imposta un valore per la proprietà di una barra
-      opzione: opzione da cambiare (per una lista di opzioni, consultare /set weechat.bar.<barname>.*)
-       valore: nuovo valore per l'opzione
-         hide: nasconde una barra
-         show: mostra una barra nascosta
-       toggle: nasconde/mostra una barra
-       scroll: scorre una barra
-     finestra: numero della finestra (usare '*' per la finestra corrente o le barre root)
- scroll_value: valore per lo scorrimento: 'x' o 'y', seguite da '+', '-', 'b' (inizio) or 'e' (fine), valore (per +/-), e %% opzionale (per scorrere di %% di larghezza/altezza, altrimenti il valore è il numero di caratteri)
+         list: list all bars
+     listfull: list all bars (verbose)
+    listitems: list all bar items
+          add: add a new bar
+         name: name of bar (must be unique)
+         type:   root: outside windows,
+               window: inside windows, with optional conditions (see below)
+    condition: condition(s) for displaying bar (only for type "window"):
+                 active: on active window
+               inactive: on inactive windows
+               nicklist: on windows with nicklist
+               other condition: see /help weechat.bar.xxx.conditions and /help eval
+               without condition, the bar is always displayed
+     position: bottom, top, left or right
+         size: size of bar (in chars)
+    separator: 1 for using separator (line), 0 or nothing means no separator
+    item1,...: items for this bar (items can be separated by comma (space between items) or "+" (glued items))
+      default: create a default bar (all default bars if no bar name is given)
+          del: delete a bar (or all bars with -all)
+          set: set a value for a bar property
+       option: option to change (for options list, look at /set weechat.bar.<barname>.*)
+        value: new value for option
+         hide: hide a bar
+         show: show an hidden bar
+       toggle: hide/show a bar
+       scroll: scroll bar
+       window: window number (use '*' for current window or for root bars)
+ scroll_value: value for scroll: 'x' or 'y' (optional), followed by '+', '-', 'b' (beginning) or 'e' (end), value (for +/-), and optional % (to scroll by % of width/height, otherwise value is number of chars)
 
-Esempi:
-  crea una barra con l'ora, numero del buffer + nome, e completamento:
-    /bar add miabarra root bottom 1 0 [time],buffer_number+:+buffer_name,completion
-  nasconde una barra:
-    /bar hide miabarra
-  scorre la lista nick di 10 righe in basso sul buffer corrente:
+Examples:
+  create a bar with time, buffer number + name, and completion:
+    /bar add mybar root bottom 1 0 [time],buffer_number+:+buffer_name,completion
+  hide a bar:
+    /bar hide mybar
+  scroll nicklist 10 lines down on current buffer:
     /bar scroll nicklist * y+10
-  scorre fino alla fine della lista nick sul buffer corrente:
+  scroll to end of nicklist on current buffer:
     /bar scroll nicklist * ye
 ........................................
 
@@ -199,6 +200,60 @@ infolists: mostra informazioni sulle liste info
   windows: mostra l'albero delle finestre
 ........................................
 
+[[command_weechat_eval]]
+[command]*`eval`* evaluate expression and send result to buffer::
+........................................
+/eval  [-n] <expression>
+       [-n] <expression1> <operator> <expression2>
+
+        -n: display result without sending it to buffer (debug mode)
+expression: expression to evaluate, variables with format ${variable} are replaced (see below)
+  operator: a logical or comparison operator:
+            - logical operators:
+                &&  boolean "and"
+                ||  boolean "or"
+            - comparison operators:
+                ==  equal
+                !=  not equal
+                <=  less or equal
+                <   less
+                >=  greater or equal
+                >   greater
+                =~  is matching regex
+                !~  is NOT matching regex
+
+An expression is considered as "true" if it is not NULL, not empty, and different from "0".
+The comparison is made using integers if the two expressions are valid integers.
+To force a string comparison, add double quotes around each expression, for example:
+  50 > 100      ==> 0
+  "50" > "100"  ==> 1
+
+Some variables are replaced in expression, using the format ${variable}, variable can be, by order of prioity :
+  1. the name of an option (file.section.option)
+  2. a hdata name/variable (the value is automatically converted to string), by default "window" and "buffer" point to current window/buffer.
+Format for hdata can be one of following:
+  hdata.var1.var2...: start with a hdata (pointer must be known), and ask variables one after one (other hdata can be followed)
+  hdata(list).var1.var2...: start with a hdata using a list, for example:
+    ${buffer[gui_buffers].full_name}: full name of first buffer in linked list of buffers
+    ${plugin[weechat_plugins].name}: name of first plugin in linked list of plugins
+For name of hdata and variables, please look at "Plugin API reference", function "weechat_hdata_get".
+
+Examples:
+  /eval -n ${weechat.look.scroll_amount}  ==> 3
+  /eval -n ${window}                      ==> 0x2549aa0
+  /eval -n ${window.buffer}               ==> 0x2549320
+  /eval -n ${window.buffer.full_name}     ==> core.weechat
+  /eval -n ${window.buffer.number}        ==> 1
+  /eval -n ${window.buffer.number} > 2    ==> 0
+  /eval -n ${window.win_width} > 100      ==> 1
+  /eval -n (8 > 12) || (5 > 2)            ==> 1
+  /eval -n (8 > 12) && (5 > 2)            ==> 0
+  /eval -n abcd =~ ^ABC                   ==> 1
+  /eval -n abcd =~ (?-i)^ABC              ==> 0
+  /eval -n abcd =~ (?-i)^abc              ==> 1
+  /eval -n abcd !~ abc                    ==> 0
+........................................
+
 [[command_weechat_filter]]
 [command]*`filter`* filtra messaggi nei buffer, per nascondere/mostrare in base a tag o regexp::
 ........................................
diff --git a/doc/it/weechat_plugin_api.it.txt b/doc/it/weechat_plugin_api.it.txt
index 07f9c2288..8f5697b61 100644
--- a/doc/it/weechat_plugin_api.it.txt
+++ b/doc/it/weechat_plugin_api.it.txt
@@ -1635,6 +1635,62 @@ str2 = weechat.string_input_for_buffer("/test")  # ""
 str3 = weechat.string_input_for_buffer("//test") # "/test"
 ----------------------------------------
 
+weechat_string_eval_expression
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+_Novità nella versione 0.4.0._
+
+// TRANSLATION MISSING
+Evaluate an expression and return result as a string.
+Special variables with format `${variable}` are expanded (see command `/eval` in
+'WeeChat User's guide').
+
+Prototipo:
+
+[source,C]
+----------------------------------------
+char *weechat_string_eval_expression (const char *expr,
+                                      struct t_hashtable *pointers,
+                                      struct t_hashtable *extra_vars);
+----------------------------------------
+
+Argomenti:
+
+// TRANSLATION MISSING
+* 'expr': the expression to evaluate
+* 'pointers': hashtable with pointers (keys must be string, values must be
+  pointer); pointers "window" and "buffer" are automatically added if they are
+  not in hashtable (with pointer to current window/buffer) (can be NULL)
+* 'extra_vars': extra variables that will be expanded (can be NULL)
+
+Valore restituito:
+
+// TRANSLATION MISSING
+* evaluated expression (must be freed by calling "free" after use), or NULL
+  if problem (invalid expression or not enough memory)
+
+Esempi in C:
+
+[source,C]
+----------------------------------------
+char *str1 = weechat_string_eval_expression ("${buffer.full_name}", NULL, NULL);       /* "core.weechat" */
+char *str2 = weechat_string_eval_expression ("${window.win_width} > 100", NULL, NULL); /* "1" */
+char *str3 = weechat_string_eval_expression ("abc =~ def", NULL, NULL);                /* "0" */
+----------------------------------------
+
+Script (Python):
+
+[source,python]
+----------------------------------------
+# prototipo
+str = weechat.string_eval_expression(expr, pointers, extra_vars)
+
+# esempi
+str1 = weechat.string_input_for_buffer("${buffer.full_name}", {}, {})       # "core.weechat"
+str2 = weechat.string_input_for_buffer("${window.win_width} > 100", {}, {}) # "1"
+str3 = weechat.string_input_for_buffer("abc =~ def", {}, {})                # "0"
+----------------------------------------
+
 [[utf-8]]
 UTF-8
 ~~~~~
diff --git a/doc/it/weechat_user.it.txt b/doc/it/weechat_user.it.txt
index 2ea159ac0..c45cba988 100644
--- a/doc/it/weechat_user.it.txt
+++ b/doc/it/weechat_user.it.txt
@@ -568,6 +568,219 @@ Esempio di split orizzontale + verticale:
                   (buffer #3)
 ........................................
 
+// TRANSLATION MISSING
+[[bars]]
+Bars
+~~~~
+
+A 'bar' is an area beside the chat that can contain any type of text.
+
+The bar options can be set with options `weechat.bar.name.option` where `name`
+is the name of the bar and `option` the option for this bar.
+
+List of bar options:
+
+[width="100%",cols="2m,2,10",options="header"]
+|========================================
+| Option | Values | Description
+
+| type | `root`, `window` |
+  A bar with type `root` is displayed exactly one time on screen, outside all
+  windows. There is no root bar by default, but an example is the bar 'buffers'
+  created by script 'buffers.pl' (sidebar with list of buffers). +
+  A bar with type `window` is displayed in each window, for example if you
+  split one time the screen (with `/window splith` or `/window splitv`), you
+  will have one bar in each window. The four default bars ('title', 'status',
+  'input', 'nicklist') have type `window`.
+
+| position | `top`, `bottom`, `left`, `right` |
+  Position of the bar: above/below chat, on the left/right.
+
+| priority | integer ≥ 0 |
+  Priority for display of bar: this is used for ordering the bars on screen when
+  many bars have same type and position. +
+  The bars are displayed from the edge of the screen to the center. A higher
+  priority will display bar at the beginning, so closer to the edge. +
+  Example: 'input' bar has priority 1000, so it is displayed before the 'status'
+  bar, which has priority 500.
+
+| size | integer ≥ 0 |
+  The size of the bar: number of columns for position left/right, number
+  of lines for position top/tobbom. A size of `0` means automatic, so the size
+  will be computed according to content displayed in bar.
+
+| size_max | integer ≥ 0 |
+  The maximum size for a bar, `0` = no limit (this option is used only if
+  `size` = `0`).
+
+| color_bg | color |
+  The default background color for the bar.
+
+| color_fg | color |
+  The default text color for the bar.
+
+| color_delim | color |
+  The color for delimiters in bar.
+
+| hidden | `on`, `off` |
+  When option is `on`, the bar is hidden. +
+  Note: instead of changing this option, the command `/bar` is preferred, for
+  example: `/bar toggle nicklist` (see command <<command_weechat_bar,/bar>>).
+
+| separator | `on`, `off` |
+  When option is `on`, a separator (line) is displayed between this bar and
+  other bars (or chat).
+
+| items | string |
+  A list of 'items' (see <<bar_items,items>> for more info).
+
+| filling_left_right | `horizontal`, `vertical`, `columns_horizontal`, `columns_vertical` |
+  Type of filling for a bar which has position `left` or `right` (see
+  <<bar_filling,filling>> for more info).
+
+| filling_top_bottom | `horizontal`, `vertical`, `columns_horizontal`, `columns_vertical` |
+  Type of filling for a bar which has position `top` or `bottom` (see
+  <<bar_filling,filling>> for more info).
+
+| conditions | string |
+  The conditions to display the bar (see <<bar_conditions,conditions>> for more
+  info).
+|========================================
+
+[[bar_items]]
+Items
+^^^^^
+
+The option 'items' is a string with a list of bar items, separated by a comma
+(space between items on screen) or "+" (glued items).
+
+The list of bar items is displayed with command `/bar listitems`.
+
+Example of bar with items "[time],buffer_number+:+buffer_plugin+.+buffer_name":
+
+........................................
+┌─────────────────────────────────────────────────────────────────────────────────────────┐
+│[12:55] 3:irc/freenode.#weechat                                                          │
+└─────────────────────────────────────────────────────────────────────────────────────────┘
+........................................
+
+[[bar_filling]]
+Filling
+^^^^^^^
+
+There are four types of filling:
+
+* `horizontal`: the items are displayed horizontally, from left to right. If
+  there are new lines in items, a space is used to separate lines.
+* `vertical`: the items are displayed from top to bottom. If there are new
+  lines in items, a new line is used to separate lines.
+* `columns_horizontal`: items are displayed using columns, where text is
+  aligned on the left. The first item is on top left, the second is on same
+  line, on the right.
+* `columns_vertical`: items are displayed using columns, where text is aligned
+  on the left. The first item is on top left, the second is one line below.
+
+Default bars 'title', 'status' and 'input' have 'horizontal' filling, and
+default bar 'nicklist' has 'vertical' filling.
+
+Some examples of filling for bar 'nicklist':
+
+........................................
+┌──────────────────────────────────────────────────┐
+│Welcome to #test, this is a test channel          │
+│12:54:15 peter | hey!                    │@carl   │
+│12:55:01  +Max | hello                   │@jessika│
+│                                         │@maddy  │
+│                                         │%Diego  │
+│                                         │%Melody │
+│                                         │+Max    │
+│                                         │ celia  │
+│                                         │ Eva    │
+│                                         │ freddy │
+│                                         │ Harold^│
+│                                         │ henry4 │
+│                                         │ jimmy17│
+│                                         │ jodie ▼│
+│[12:55] [6] [irc/freenode] 3:#test(+n){24}        │
+└──────────────────────────────────────────────────┘
+                filling_left_right = vertical ▲
+
+┌──────────────────────────────────────────────────┐
+│Welcome to #test, this is a test channel          │
+│12:54:15 peter | hey!           │@carl     lee    │
+│12:55:01  +Max | hello          │@jessika  louise │
+│                                │@maddy    mario  │
+│                                │%Diego    mark   │
+│                                │%Melody   peter  │
+│                                │+Max      Rachel │
+│                                │ celia    richard│
+│                                │ Eva      sheryl │
+│                                │ freddy   Vince  │
+│                                │ Harold^  warren │
+│                                │ henry4   zack   │
+│                                │ jimmy17         │
+│                                │ jodie           │
+│[12:55] [6] [irc/freenode] 3:#test(+n){24}        │
+└──────────────────────────────────────────────────┘
+        filling_left_right = columns_vertical ▲
+
+┌───────────────────────────────────────────────────────────────────────┐
+│@carl    %Diego    celia    Harold^  jodie    mario    Rachel   Vince  │
+│@jessika %Melody   Eva      henry4   lee      mark     richard  warren │
+│@maddy   +Max      freddy   jimmy17  louise   peter    sheryl   zack   │
+│───────────────────────────────────────────────────────────────────────│
+│                                                                       │
+        filling_top_bottom = columns_vertical ▲
+
+┌───────────────────────────────────────────────────────────────────────┐
+│@carl    @jessika @maddy   %Diego   %Melody  +Max      celia    Eva    │
+│ freddy   Harold^  henry4   jimmy17  jodie    lee      louise   mario  │
+│ mark     peter    Rachel   richard  sheryl   Vince    warren   zack   │
+│───────────────────────────────────────────────────────────────────────│
+│                                                                       │
+      filling_top_bottom = columns_horizontal ▲
+........................................
+
+[[bar_conditions]]
+Conditions
+^^^^^^^^^^
+
+The option 'conditions' is a string evaluated to know if the bar is displayed
+or not in the window (it is used only for bars with type 'window').
+
+The string can be:
+
+* 'active': the window must be active
+* 'inactive': the window must be inactive
+* 'nicklist': the buffer displayed in window must have a nicklist
+* an expression: it is evaluated as boolean (see command
+  <<command_weechat_eval,/eval>>)
+
+For the expression, following variables are available:
+
+* `${active}`: true if window is active
+* `${inactive}`: true if window is inactive
+* `$[nicklist}`: true if buffer displayed in window has a nicklist
+
+Following pointers are available:
+
+* `${window}`: the window where condition is evaluated
+* `${buffer}`: the buffer of window where condition is evaluated
+
+Exemple to display nicklist bar in all buffers with a nicklist, and only if
+width of window is > 100 :
+
+----------------------------------------
+/set weechat.bar.nicklist.conditions "${nicklist} && ${window.win_width} > 100"
+----------------------------------------
+
+Same condition, but always display nicklist on buffer '&bitlbee' (even if window
+is small):
+
+----------------------------------------
+/set weechat.bar.nicklist.conditions "${nicklist} && (${window.win_width} > 100 || ${buffer.full_name} == irc.bitlbee.&bitlbee)"
+----------------------------------------
+
 [[notify_levels]]
 Livelli di notifica
 ~~~~~~~~~~~~~~~~~~~
diff --git a/doc/ja/autogen/plugin_api/hdata.txt b/doc/ja/autogen/plugin_api/hdata.txt
index dbfa893f8..430ccadf1 100644
--- a/doc/ja/autogen/plugin_api/hdata.txt
+++ b/doc/ja/autogen/plugin_api/hdata.txt
@@ -325,8 +325,6 @@
 | weechat | bar | バー |
   'name' (string) +
   'options' (pointer) +
-  'conditions_count' (integer) +
-  'conditions_array' (string, array_size: "conditions_count") +
   'items_count' (integer) +
   'items_subcount' (pointer) +
   'items_array' (pointer) +
diff --git a/doc/ja/autogen/user/weechat_commands.txt b/doc/ja/autogen/user/weechat_commands.txt
index 49c1a5286..9bf0c3a08 100644
--- a/doc/ja/autogen/user/weechat_commands.txt
+++ b/doc/ja/autogen/user/weechat_commands.txt
@@ -11,49 +11,50 @@ message: 離席メッセージ (メッセージが無い場合は、離席状態
 [command]*`bar`* バーの管理::
 ........................................
 /bar  list|listfull|listitems
-      add <name> <type>[,<cond1>[,<cond2>...]] <position> <size> <separator> <item1>[,<item2>...]
+      add <name> <type>[,<condition>] <position> <size> <separator> <item1>[,<item2>...]
       default [input|title|status|nicklist]
       del <name>|-all
       set <name> <option> <value>
       hide|show|toggle <name>
       scroll <name> <window> <scroll_value>
 
-         list: 全てのバーをリストアップ
-     listfull: 全てのバーをリストアップ (詳細)
-    listitems: 全てのバーアイテムをリストアップ
-          add: 新しいバーを追加
-         name: バーの名称 (ユニークな)
-         type:   root: 外側のウィンドウ、
-               window: 内側のウィンドウ、任意の状態を取れる (以下を参照)
-    cond1,...: バーの表示状態 (タイプが "window" のバー以外は無効):
-                 active: アクティブウィンドウに表示
-               inactive: 非アクティブウィンドウに表示
-               nicklist: ニックネームリストを持つウィンドウに表示
-               表示状態の指定が無ければ、バーは常に表示されます。
-     position: bottom、top、left、right
-         size: バーのサイズ (文字数で指定)
-    separator: 1 はセパレータ (線) を使用、0 または指定無しはセパレータ無し
-    item1,...: バーのアイテム (アイテムはコンマ (アイテム間にスペース) または "+" (アイテム間にスペース無し) で区切ります)
-      default: デフォルトバーを作成 (バーの名前が無ければ全てのデフォルトバーが作成されます)
-          del: バーを削除 (-all を付ければ全てのバーを削除)
-          set: バー属性に値を設定
-       option: 変更するオプション (オプション一覧は /set weechat.bar.<barname>.* を参照)
-        value: オプションの新しい値
-         hide: バーを隠す
-         show: 隠されたバーを表示
-       toggle: バーの非表示/表示を切り替え
-       scroll: バーをスクロール
-       window: ウィンドウ番号 (現在のウィンドウかルートバーを指定するには '*' を使う)
- scroll_value: スクロールする量: 'x' または 'y' (任意)の後に、'+' か '-' か 'b' (最初) か 'e' (最後)の後に、値 (+/- を付けて)、任意で % (スクロールする幅/高さの割合、% が無ければ値は文字数と解釈されます)
+         list: list all bars
+     listfull: list all bars (verbose)
+    listitems: list all bar items
+          add: add a new bar
+         name: name of bar (must be unique)
+         type:   root: outside windows,
+               window: inside windows, with optional conditions (see below)
+    condition: condition(s) for displaying bar (only for type "window"):
+                 active: on active window
+               inactive: on inactive windows
+               nicklist: on windows with nicklist
+               other condition: see /help weechat.bar.xxx.conditions and /help eval
+               without condition, the bar is always displayed
+     position: bottom, top, left or right
+         size: size of bar (in chars)
+    separator: 1 for using separator (line), 0 or nothing means no separator
+    item1,...: items for this bar (items can be separated by comma (space between items) or "+" (glued items))
+      default: create a default bar (all default bars if no bar name is given)
+          del: delete a bar (or all bars with -all)
+          set: set a value for a bar property
+       option: option to change (for options list, look at /set weechat.bar.<barname>.*)
+        value: new value for option
+         hide: hide a bar
+         show: show an hidden bar
+       toggle: hide/show a bar
+       scroll: scroll bar
+       window: window number (use '*' for current window or for root bars)
+ scroll_value: value for scroll: 'x' or 'y' (optional), followed by '+', '-', 'b' (beginning) or 'e' (end), value (for +/-), and optional % (to scroll by % of width/height, otherwise value is number of chars)
 
-例:
-  時間、バー番号 + 名前、補完候補からなるバーを作成:
+Examples:
+  create a bar with time, buffer number + name, and completion:
     /bar add mybar root bottom 1 0 [time],buffer_number+:+buffer_name,completion
-  バーを隠す:
+  hide a bar:
     /bar hide mybar
-  現在のバッファに対応したニックネームリストを10行分、下方向にスクロール:
+  scroll nicklist 10 lines down on current buffer:
     /bar scroll nicklist * y+10
-  現在のバッファに対応したニックネームリストを最後までスクロール:
+  scroll to end of nicklist on current buffer:
     /bar scroll nicklist * ye
 ........................................
 
@@ -199,6 +200,60 @@ infolists: infolist に関する情報を表示
   windows: ウィンドウツリーの情報を表示
 ........................................
 
+[[command_weechat_eval]]
+[command]*`eval`* evaluate expression and send result to buffer::
+........................................
+/eval  [-n] <expression>
+       [-n] <expression1> <operator> <expression2>
+
+        -n: display result without sending it to buffer (debug mode)
+expression: expression to evaluate, variables with format ${variable} are replaced (see below)
+  operator: a logical or comparison operator:
+            - logical operators:
+                &&  boolean "and"
+                ||  boolean "or"
+            - comparison operators:
+                ==  equal
+                !=  not equal
+                <=  less or equal
+                <   less
+                >=  greater or equal
+                >   greater
+                =~  is matching regex
+                !~  is NOT matching regex
+
+An expression is considered as "true" if it is not NULL, not empty, and different from "0".
+The comparison is made using integers if the two expressions are valid integers.
+To force a string comparison, add double quotes around each expression, for example:
+  50 > 100      ==> 0
+  "50" > "100"  ==> 1
+
+Some variables are replaced in expression, using the format ${variable}, variable can be, by order of prioity :
+  1. the name of an option (file.section.option)
+  2. a hdata name/variable (the value is automatically converted to string), by default "window" and "buffer" point to current window/buffer.
+Format for hdata can be one of following:
+  hdata.var1.var2...: start with a hdata (pointer must be known), and ask variables one after one (other hdata can be followed)
+  hdata(list).var1.var2...: start with a hdata using a list, for example:
+    ${buffer[gui_buffers].full_name}: full name of first buffer in linked list of buffers
+    ${plugin[weechat_plugins].name}: name of first plugin in linked list of plugins
+For name of hdata and variables, please look at "Plugin API reference", function "weechat_hdata_get".
+
+Examples:
+  /eval -n ${weechat.look.scroll_amount}  ==> 3
+  /eval -n ${window}                      ==> 0x2549aa0
+  /eval -n ${window.buffer}               ==> 0x2549320
+  /eval -n ${window.buffer.full_name}     ==> core.weechat
+  /eval -n ${window.buffer.number}        ==> 1
+  /eval -n ${window.buffer.number} > 2    ==> 0
+  /eval -n ${window.win_width} > 100      ==> 1
+  /eval -n (8 > 12) || (5 > 2)            ==> 1
+  /eval -n (8 > 12) && (5 > 2)            ==> 0
+  /eval -n abcd =~ ^ABC                   ==> 1
+  /eval -n abcd =~ (?-i)^ABC              ==> 0
+  /eval -n abcd =~ (?-i)^abc              ==> 1
+  /eval -n abcd !~ abc                    ==> 0
+........................................
+
 [[command_weechat_filter]]
 [command]*`filter`* タグか正規表現に基づくバッファメッセージの非表示/表示::
 ........................................
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 7bb755b0d..c17d1c59a 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -12,6 +12,8 @@
 ./src/core/wee-config.h
 ./src/core/wee-debug.c
 ./src/core/wee-debug.h
+./src/core/wee-eval.c
+./src/core/wee-eval.h
 ./src/core/wee-hook.c
 ./src/core/wee-hook.h
 ./src/core/wee-infolist.c
diff --git a/po/cs.po b/po/cs.po
index c47e9a4b8..5e3a25aa8 100644
--- a/po/cs.po
+++ b/po/cs.po
@@ -20,7 +20,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat 0.4.0-dev\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2012-10-20 17:54+0200\n"
+"POT-Creation-Date: 2012-11-02 08:59+0100\n"
 "PO-Revision-Date: 2012-09-29 11:42+0200\n"
 "Last-Translator: Jiri Golembiovsky <golemj@gmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -247,6 +247,13 @@ msgstr "Hrubý obsah bufferů byl zapsán do logovacího souboru"
 msgid "Debug disabled for \"%s\""
 msgstr "Ladění vypnuto pro \"%s\""
 
+msgid "error"
+msgstr ""
+
+#, c-format
+msgid "%sError in expression to evaluate"
+msgstr ""
+
 #, c-format
 msgid "  %s[%s%s%s]%s buffer: %s%s%s / tags: %s / regex: %s %s"
 msgstr "  %s[%s%s%s]%s buffer: %s%s%s / značky: %s / regulární výraz: %s %s"
@@ -835,10 +842,10 @@ msgstr "řídit pole"
 
 #, fuzzy
 msgid ""
-"list|listfull|listitems || add <name> <type>[,<cond1>[,<cond2>...]] "
-"<position> <size> <separator> <item1>[,<item2>...] || default [input|title|"
-"status|nicklist] || del <name>|-all || set <name> <option> <value> || hide|"
-"show|toggle <name> || scroll <name> <window> <scroll_value>"
+"list|listfull|listitems || add <name> <type>[,<condition>] <position> <size> "
+"<separator> <item1>[,<item2>...] || default [input|title|status|nicklist] || "
+"del <name>|-all || set <name> <option> <value> || hide|show|toggle <name> || "
+"scroll <name> <window> <scroll_value>"
 msgstr ""
 "list|listfull|listitems || add <jméno> <typ>[,<podmínka1>[,<podmínka2>...]] "
 "<pozice> <velikost> <oddělovac> <položka1>[,<položka2>...] || default [input|"
@@ -855,11 +862,13 @@ msgid ""
 "         name: name of bar (must be unique)\n"
 "         type:   root: outside windows,\n"
 "               window: inside windows, with optional conditions (see below)\n"
-"    cond1,...: condition(s) for displaying bar (only for type \"window\"):\n"
+"    condition: condition(s) for displaying bar (only for type \"window\"):\n"
 "                 active: on active window\n"
 "               inactive: on inactive windows\n"
 "               nicklist: on windows with nicklist\n"
-"               without condition, bar is always displayed\n"
+"               other condition: see /help weechat.bar.xxx.conditions and /"
+"help eval\n"
+"               without condition, the bar is always displayed\n"
 "     position: bottom, top, left or right\n"
 "         size: size of bar (in chars)\n"
 "    separator: 1 for using separator (line), 0 or nothing means no "
@@ -1182,6 +1191,71 @@ msgstr ""
 "   term: zobrazit informace o terminálu a dostupných barvách\n"
 "windows: zobrazit strom oken"
 
+msgid "evaluate expression and send result to buffer"
+msgstr ""
+
+msgid "[-n] <expression> || [-n] <expression1> <operator> <expression2>"
+msgstr ""
+
+msgid ""
+"        -n: display result without sending it to buffer (debug mode)\n"
+"expression: expression to evaluate, variables with format ${variable} are "
+"replaced (see below)\n"
+"  operator: a logical or comparison operator:\n"
+"            - logical operators:\n"
+"                &&  boolean \"and\"\n"
+"                ||  boolean \"or\"\n"
+"            - comparison operators:\n"
+"                ==  equal\n"
+"                !=  not equal\n"
+"                <=  less or equal\n"
+"                <   less\n"
+"                >=  greater or equal\n"
+"                >   greater\n"
+"                =~  is matching regex\n"
+"                !~  is NOT matching regex\n"
+"\n"
+"An expression is considered as \"true\" if it is not NULL, not empty, and "
+"different from \"0\".\n"
+"The comparison is made using integers if the two expressions are valid "
+"integers.\n"
+"To force a string comparison, add double quotes around each expression, for "
+"example:\n"
+"  50 > 100      ==> 0\n"
+"  \"50\" > \"100\"  ==> 1\n"
+"\n"
+"Some variables are replaced in expression, using the format ${variable}, "
+"variable can be, by order of prioity :\n"
+"  1. the name of an option (file.section.option)\n"
+"  2. a hdata name/variable (the value is automatically converted to string), "
+"by default \"window\" and \"buffer\" point to current window/buffer.\n"
+"Format for hdata can be one of following:\n"
+"  hdata.var1.var2...: start with a hdata (pointer must be known), and ask "
+"variables one after one (other hdata can be followed)\n"
+"  hdata(list).var1.var2...: start with a hdata using a list, for example:\n"
+"    ${buffer[gui_buffers].full_name}: full name of first buffer in linked "
+"list of buffers\n"
+"    ${plugin[weechat_plugins].name}: name of first plugin in linked list of "
+"plugins\n"
+"For name of hdata and variables, please look at \"Plugin API reference\", "
+"function \"weechat_hdata_get\".\n"
+"\n"
+"Examples:\n"
+"  /eval -n ${weechat.look.scroll_amount}  ==> 3\n"
+"  /eval -n ${window}                      ==> 0x2549aa0\n"
+"  /eval -n ${window.buffer}               ==> 0x2549320\n"
+"  /eval -n ${window.buffer.full_name}     ==> core.weechat\n"
+"  /eval -n ${window.buffer.number}        ==> 1\n"
+"  /eval -n ${window.buffer.number} > 2    ==> 0\n"
+"  /eval -n ${window.win_width} > 100      ==> 1\n"
+"  /eval -n (8 > 12) || (5 > 2)            ==> 1\n"
+"  /eval -n (8 > 12) && (5 > 2)            ==> 0\n"
+"  /eval -n abcd =~ ^ABC                   ==> 1\n"
+"  /eval -n abcd =~ (?-i)^ABC              ==> 0\n"
+"  /eval -n abcd =~ (?-i)^abc              ==> 1\n"
+"  /eval -n abcd !~ abc                    ==> 0"
+msgstr ""
+
 msgid ""
 "filter messages in buffers, to hide/show them according to tags or regex"
 msgstr ""
@@ -2224,6 +2298,11 @@ msgstr "alias pro barvu"
 msgid "%sError: palette option must be numeric"
 msgstr "%sChyba: voleba palety musí být číselná"
 
+#, fuzzy, c-format
+msgid "%sWarning: unknown option for section \"%s\": %s (value: \"%s\")"
+msgstr ""
+"%sUpozornění: %s, řádek %d: nastavení \"%s\" je neznámé pro sekci \"%s\""
+
 msgid "Notify level for buffer"
 msgstr "Úroveň upozornění pro buffer"
 
@@ -3369,9 +3448,11 @@ msgid "bar type (root, window, window_active, window_inactive)"
 msgstr "typ pole (root, window, window_active, window_inactive)"
 
 msgid ""
-"condition(s) for displaying bar (for bars of type \"window\"): \"active\" = "
-"window must be active, \"inactive\" = window must be inactive, \"nicklist\" "
-"= buffer must have a nicklist"
+"condition(s) for displaying bar (for bars of type \"window\"): a simple "
+"condition: \"active\", \"inactive\", \"nicklist\" (window must be active/"
+"inactive, buffer must have a nicklist), or an expression with condition(s) "
+"(see /help eval), like: \"${nicklist} && ${window.win_width} > 100\" (local "
+"variables for expression are ${active}, ${inactive} and ${nicklist})"
 msgstr ""
 
 msgid "bar position (bottom, top, left, right)"
diff --git a/po/de.po b/po/de.po
index d17bb8f23..23db423a6 100644
--- a/po/de.po
+++ b/po/de.po
@@ -23,7 +23,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat 0.3.7-dev\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2012-10-20 17:54+0200\n"
+"POT-Creation-Date: 2012-11-02 08:59+0100\n"
 "PO-Revision-Date: 2012-10-19 17:57+0100\n"
 "Last-Translator: Nils Görs <weechatter@arcor.de>\n"
 "Language-Team: German <weechatter@arcor.de>\n"
@@ -265,6 +265,13 @@ msgstr ""
 msgid "Debug disabled for \"%s\""
 msgstr "Debug-Modus für \"%s\" deaktiviert"
 
+msgid "error"
+msgstr ""
+
+#, c-format
+msgid "%sError in expression to evaluate"
+msgstr ""
+
 #, c-format
 msgid "  %s[%s%s%s]%s buffer: %s%s%s / tags: %s / regex: %s %s"
 msgstr "  %s[%s%s%s]%s Buffer: %s%s%s / Schlagwörter: %s / regex: %s %s"
@@ -853,17 +860,19 @@ msgstr ""
 msgid "manage bars"
 msgstr "Infobars verwalten"
 
+#, fuzzy
 msgid ""
-"list|listfull|listitems || add <name> <type>[,<cond1>[,<cond2>...]] "
-"<position> <size> <separator> <item1>[,<item2>...] || default [input|title|"
-"status|nicklist] || del <name>|-all || set <name> <option> <value> || hide|"
-"show|toggle <name> || scroll <name> <window> <scroll_value>"
+"list|listfull|listitems || add <name> <type>[,<condition>] <position> <size> "
+"<separator> <item1>[,<item2>...] || default [input|title|status|nicklist] || "
+"del <name>|-all || set <name> <option> <value> || hide|show|toggle <name> || "
+"scroll <name> <window> <scroll_value>"
 msgstr ""
 "list|listfull|listitems || add <name> <type>[,<cond1>[,<cond2>...]] "
 "<position> <size> <separator> <item1>[,<item2>...] || default [input|title|"
 "status|nicklist] || del <name>|-all || set <name> <option> <value> || hide|"
 "show|toggle <name> || scroll <name> <window> <scroll_value>"
 
+#, fuzzy
 msgid ""
 "         list: list all bars\n"
 "     listfull: list all bars (verbose)\n"
@@ -872,11 +881,13 @@ msgid ""
 "         name: name of bar (must be unique)\n"
 "         type:   root: outside windows,\n"
 "               window: inside windows, with optional conditions (see below)\n"
-"    cond1,...: condition(s) for displaying bar (only for type \"window\"):\n"
+"    condition: condition(s) for displaying bar (only for type \"window\"):\n"
 "                 active: on active window\n"
 "               inactive: on inactive windows\n"
 "               nicklist: on windows with nicklist\n"
-"               without condition, bar is always displayed\n"
+"               other condition: see /help weechat.bar.xxx.conditions and /"
+"help eval\n"
+"               without condition, the bar is always displayed\n"
 "     position: bottom, top, left or right\n"
 "         size: size of bar (in chars)\n"
 "    separator: 1 for using separator (line), 0 or nothing means no "
@@ -1239,6 +1250,71 @@ msgstr ""
 "     term: gibt Informationen über das Terminal und verfügbare Farben aus\n"
 "  windows: zeigt die Fensterstruktur an"
 
+msgid "evaluate expression and send result to buffer"
+msgstr ""
+
+msgid "[-n] <expression> || [-n] <expression1> <operator> <expression2>"
+msgstr ""
+
+msgid ""
+"        -n: display result without sending it to buffer (debug mode)\n"
+"expression: expression to evaluate, variables with format ${variable} are "
+"replaced (see below)\n"
+"  operator: a logical or comparison operator:\n"
+"            - logical operators:\n"
+"                &&  boolean \"and\"\n"
+"                ||  boolean \"or\"\n"
+"            - comparison operators:\n"
+"                ==  equal\n"
+"                !=  not equal\n"
+"                <=  less or equal\n"
+"                <   less\n"
+"                >=  greater or equal\n"
+"                >   greater\n"
+"                =~  is matching regex\n"
+"                !~  is NOT matching regex\n"
+"\n"
+"An expression is considered as \"true\" if it is not NULL, not empty, and "
+"different from \"0\".\n"
+"The comparison is made using integers if the two expressions are valid "
+"integers.\n"
+"To force a string comparison, add double quotes around each expression, for "
+"example:\n"
+"  50 > 100      ==> 0\n"
+"  \"50\" > \"100\"  ==> 1\n"
+"\n"
+"Some variables are replaced in expression, using the format ${variable}, "
+"variable can be, by order of prioity :\n"
+"  1. the name of an option (file.section.option)\n"
+"  2. a hdata name/variable (the value is automatically converted to string), "
+"by default \"window\" and \"buffer\" point to current window/buffer.\n"
+"Format for hdata can be one of following:\n"
+"  hdata.var1.var2...: start with a hdata (pointer must be known), and ask "
+"variables one after one (other hdata can be followed)\n"
+"  hdata(list).var1.var2...: start with a hdata using a list, for example:\n"
+"    ${buffer[gui_buffers].full_name}: full name of first buffer in linked "
+"list of buffers\n"
+"    ${plugin[weechat_plugins].name}: name of first plugin in linked list of "
+"plugins\n"
+"For name of hdata and variables, please look at \"Plugin API reference\", "
+"function \"weechat_hdata_get\".\n"
+"\n"
+"Examples:\n"
+"  /eval -n ${weechat.look.scroll_amount}  ==> 3\n"
+"  /eval -n ${window}                      ==> 0x2549aa0\n"
+"  /eval -n ${window.buffer}               ==> 0x2549320\n"
+"  /eval -n ${window.buffer.full_name}     ==> core.weechat\n"
+"  /eval -n ${window.buffer.number}        ==> 1\n"
+"  /eval -n ${window.buffer.number} > 2    ==> 0\n"
+"  /eval -n ${window.win_width} > 100      ==> 1\n"
+"  /eval -n (8 > 12) || (5 > 2)            ==> 1\n"
+"  /eval -n (8 > 12) && (5 > 2)            ==> 0\n"
+"  /eval -n abcd =~ ^ABC                   ==> 1\n"
+"  /eval -n abcd =~ (?-i)^ABC              ==> 0\n"
+"  /eval -n abcd =~ (?-i)^abc              ==> 1\n"
+"  /eval -n abcd !~ abc                    ==> 0"
+msgstr ""
+
 msgid ""
 "filter messages in buffers, to hide/show them according to tags or regex"
 msgstr ""
@@ -2438,6 +2514,10 @@ msgstr "Alias für Farbe"
 msgid "%sError: palette option must be numeric"
 msgstr "%sFehler: Option Palette muss numerisch sein"
 
+#, fuzzy, c-format
+msgid "%sWarning: unknown option for section \"%s\": %s (value: \"%s\")"
+msgstr "%sWarnung: %s, Zeile %d: unbekannte Option für Sektion \"%s\": %s"
+
 msgid "Notify level for buffer"
 msgstr "Benachrichtigungsstufe für Buffer"
 
@@ -3738,13 +3818,12 @@ msgid "bar type (root, window, window_active, window_inactive)"
 msgstr "Bar-Typ (root, window, window_active, window_inactive)"
 
 msgid ""
-"condition(s) for displaying bar (for bars of type \"window\"): \"active\" = "
-"window must be active, \"inactive\" = window must be inactive, \"nicklist\" "
-"= buffer must have a nicklist"
+"condition(s) for displaying bar (for bars of type \"window\"): a simple "
+"condition: \"active\", \"inactive\", \"nicklist\" (window must be active/"
+"inactive, buffer must have a nicklist), or an expression with condition(s) "
+"(see /help eval), like: \"${nicklist} && ${window.win_width} > 100\" (local "
+"variables for expression are ${active}, ${inactive} and ${nicklist})"
 msgstr ""
-"Bedingung(en) um eine Bar anzuzeigen (gilt für Bars des Typs \"window\"): "
-"\"active\" = window muss aktiv sein \"inactive\" = window muss inaktiv sein, "
-"\"nicklist\" = Buffer muss über eine Nickliste verfügen"
 
 msgid "bar position (bottom, top, left, right)"
 msgstr "Position der Infobar (unten, oben, links, rechts)"
@@ -9856,6 +9935,15 @@ msgstr "Type"
 msgid "Constants"
 msgstr "Konstanten"
 
+#~ msgid ""
+#~ "condition(s) for displaying bar (for bars of type \"window\"): \"active\" "
+#~ "= window must be active, \"inactive\" = window must be inactive, "
+#~ "\"nicklist\" = buffer must have a nicklist"
+#~ msgstr ""
+#~ "Bedingung(en) um eine Bar anzuzeigen (gilt für Bars des Typs \"window\"): "
+#~ "\"active\" = window muss aktiv sein \"inactive\" = window muss inaktiv "
+#~ "sein, \"nicklist\" = Buffer muss über eine Nickliste verfügen"
+
 #~ msgid ""
 #~ "server: server name\n"
 #~ "  nick: nick (may be a mask)"
diff --git a/po/es.po b/po/es.po
index 5ba44fb5f..005918e54 100644
--- a/po/es.po
+++ b/po/es.po
@@ -22,7 +22,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat 0.4.0-dev\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2012-10-20 17:54+0200\n"
+"POT-Creation-Date: 2012-11-02 08:59+0100\n"
 "PO-Revision-Date: 2012-09-29 11:42+0200\n"
 "Last-Translator: Elián Hanisch <lambdae2@gmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -253,6 +253,13 @@ msgstr ""
 msgid "Debug disabled for \"%s\""
 msgstr "Depurado de \"%s\" desactivado"
 
+msgid "error"
+msgstr ""
+
+#, c-format
+msgid "%sError in expression to evaluate"
+msgstr ""
+
 #, c-format
 msgid "  %s[%s%s%s]%s buffer: %s%s%s / tags: %s / regex: %s %s"
 msgstr "  %s[%s%s%s]%s buffer: %s%s%s / etiquetas: %s / expresión: %s %s"
@@ -836,11 +843,12 @@ msgstr ""
 msgid "manage bars"
 msgstr "gestionar las barras"
 
+#, fuzzy
 msgid ""
-"list|listfull|listitems || add <name> <type>[,<cond1>[,<cond2>...]] "
-"<position> <size> <separator> <item1>[,<item2>...] || default [input|title|"
-"status|nicklist] || del <name>|-all || set <name> <option> <value> || hide|"
-"show|toggle <name> || scroll <name> <window> <scroll_value>"
+"list|listfull|listitems || add <name> <type>[,<condition>] <position> <size> "
+"<separator> <item1>[,<item2>...] || default [input|title|status|nicklist] || "
+"del <name>|-all || set <name> <option> <value> || hide|show|toggle <name> || "
+"scroll <name> <window> <scroll_value>"
 msgstr ""
 "list|listfull|listitems || add <nombre> <tipo>[,<cond1>[,<cond2>...]] "
 "<posición> <tamaño> <separador> <elemento1>[,<elemento2>...] || default "
@@ -848,6 +856,7 @@ msgstr ""
 "<valor> || hide|show|toggle <nombre> || scroll <nombre> <ventana> "
 "<desplazamiento>"
 
+#, fuzzy
 msgid ""
 "         list: list all bars\n"
 "     listfull: list all bars (verbose)\n"
@@ -856,11 +865,13 @@ msgid ""
 "         name: name of bar (must be unique)\n"
 "         type:   root: outside windows,\n"
 "               window: inside windows, with optional conditions (see below)\n"
-"    cond1,...: condition(s) for displaying bar (only for type \"window\"):\n"
+"    condition: condition(s) for displaying bar (only for type \"window\"):\n"
 "                 active: on active window\n"
 "               inactive: on inactive windows\n"
 "               nicklist: on windows with nicklist\n"
-"               without condition, bar is always displayed\n"
+"               other condition: see /help weechat.bar.xxx.conditions and /"
+"help eval\n"
+"               without condition, the bar is always displayed\n"
 "     position: bottom, top, left or right\n"
 "         size: size of bar (in chars)\n"
 "    separator: 1 for using separator (line), 0 or nothing means no "
@@ -1216,6 +1227,71 @@ msgstr ""
 "     term: muestra información sobre la terminal.\n"
 "  windows: muestra el árbol de ventanas."
 
+msgid "evaluate expression and send result to buffer"
+msgstr ""
+
+msgid "[-n] <expression> || [-n] <expression1> <operator> <expression2>"
+msgstr ""
+
+msgid ""
+"        -n: display result without sending it to buffer (debug mode)\n"
+"expression: expression to evaluate, variables with format ${variable} are "
+"replaced (see below)\n"
+"  operator: a logical or comparison operator:\n"
+"            - logical operators:\n"
+"                &&  boolean \"and\"\n"
+"                ||  boolean \"or\"\n"
+"            - comparison operators:\n"
+"                ==  equal\n"
+"                !=  not equal\n"
+"                <=  less or equal\n"
+"                <   less\n"
+"                >=  greater or equal\n"
+"                >   greater\n"
+"                =~  is matching regex\n"
+"                !~  is NOT matching regex\n"
+"\n"
+"An expression is considered as \"true\" if it is not NULL, not empty, and "
+"different from \"0\".\n"
+"The comparison is made using integers if the two expressions are valid "
+"integers.\n"
+"To force a string comparison, add double quotes around each expression, for "
+"example:\n"
+"  50 > 100      ==> 0\n"
+"  \"50\" > \"100\"  ==> 1\n"
+"\n"
+"Some variables are replaced in expression, using the format ${variable}, "
+"variable can be, by order of prioity :\n"
+"  1. the name of an option (file.section.option)\n"
+"  2. a hdata name/variable (the value is automatically converted to string), "
+"by default \"window\" and \"buffer\" point to current window/buffer.\n"
+"Format for hdata can be one of following:\n"
+"  hdata.var1.var2...: start with a hdata (pointer must be known), and ask "
+"variables one after one (other hdata can be followed)\n"
+"  hdata(list).var1.var2...: start with a hdata using a list, for example:\n"
+"    ${buffer[gui_buffers].full_name}: full name of first buffer in linked "
+"list of buffers\n"
+"    ${plugin[weechat_plugins].name}: name of first plugin in linked list of "
+"plugins\n"
+"For name of hdata and variables, please look at \"Plugin API reference\", "
+"function \"weechat_hdata_get\".\n"
+"\n"
+"Examples:\n"
+"  /eval -n ${weechat.look.scroll_amount}  ==> 3\n"
+"  /eval -n ${window}                      ==> 0x2549aa0\n"
+"  /eval -n ${window.buffer}               ==> 0x2549320\n"
+"  /eval -n ${window.buffer.full_name}     ==> core.weechat\n"
+"  /eval -n ${window.buffer.number}        ==> 1\n"
+"  /eval -n ${window.buffer.number} > 2    ==> 0\n"
+"  /eval -n ${window.win_width} > 100      ==> 1\n"
+"  /eval -n (8 > 12) || (5 > 2)            ==> 1\n"
+"  /eval -n (8 > 12) && (5 > 2)            ==> 0\n"
+"  /eval -n abcd =~ ^ABC                   ==> 1\n"
+"  /eval -n abcd =~ (?-i)^ABC              ==> 0\n"
+"  /eval -n abcd =~ (?-i)^abc              ==> 1\n"
+"  /eval -n abcd !~ abc                    ==> 0"
+msgstr ""
+
 msgid ""
 "filter messages in buffers, to hide/show them according to tags or regex"
 msgstr ""
@@ -2348,6 +2424,11 @@ msgstr "alias para el color"
 msgid "%sError: palette option must be numeric"
 msgstr "%sError: el valor de la paleta debe ser un número"
 
+#, fuzzy, c-format
+msgid "%sWarning: unknown option for section \"%s\": %s (value: \"%s\")"
+msgstr ""
+"%sAtención: %s, línea %d: opción desconocida para la sección \"%s\": %s"
+
 msgid "Notify level for buffer"
 msgstr "Nivel de notificación para el buffer"
 
@@ -3559,13 +3640,12 @@ msgid "bar type (root, window, window_active, window_inactive)"
 msgstr "tipo de barra (root, window, window_active, window_inactive)"
 
 msgid ""
-"condition(s) for displaying bar (for bars of type \"window\"): \"active\" = "
-"window must be active, \"inactive\" = window must be inactive, \"nicklist\" "
-"= buffer must have a nicklist"
+"condition(s) for displaying bar (for bars of type \"window\"): a simple "
+"condition: \"active\", \"inactive\", \"nicklist\" (window must be active/"
+"inactive, buffer must have a nicklist), or an expression with condition(s) "
+"(see /help eval), like: \"${nicklist} && ${window.win_width} > 100\" (local "
+"variables for expression are ${active}, ${inactive} and ${nicklist})"
 msgstr ""
-"condicion(es) para mostrar barras del tipo \"window\": \"active\" = la "
-"ventana debe estar activa, \"inactive\" = la ventana deber estar inactiva, "
-"\"nicklist\" = buffer debe tener una lista de apodos"
 
 msgid "bar position (bottom, top, left, right)"
 msgstr "posición de la barra (bottom, top, left, right)"
@@ -9403,6 +9483,15 @@ msgstr "Tipo"
 msgid "Constants"
 msgstr "Constantes"
 
+#~ msgid ""
+#~ "condition(s) for displaying bar (for bars of type \"window\"): \"active\" "
+#~ "= window must be active, \"inactive\" = window must be inactive, "
+#~ "\"nicklist\" = buffer must have a nicklist"
+#~ msgstr ""
+#~ "condicion(es) para mostrar barras del tipo \"window\": \"active\" = la "
+#~ "ventana debe estar activa, \"inactive\" = la ventana deber estar "
+#~ "inactiva, \"nicklist\" = buffer debe tener una lista de apodos"
+
 #~ msgid ""
 #~ "server: server name\n"
 #~ "  nick: nick (may be a mask)"
diff --git a/po/fr.po b/po/fr.po
index 00e424d2d..dbdbd5e00 100644
--- a/po/fr.po
+++ b/po/fr.po
@@ -21,8 +21,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat 0.4.0-dev\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2012-10-20 17:54+0200\n"
-"PO-Revision-Date: 2012-10-20 17:54+0200\n"
+"POT-Creation-Date: 2012-11-02 08:59+0100\n"
+"PO-Revision-Date: 2012-10-27 12:51+0200\n"
 "Last-Translator: Sebastien Helleu <flashcode@flashtux.org>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
 "Language: French\n"
@@ -252,6 +252,13 @@ msgstr "Le contenu brut des tampons a été écrit dans le fichier de log"
 msgid "Debug disabled for \"%s\""
 msgstr "Debug désactivé pour \"%s\""
 
+msgid "error"
+msgstr "erreur"
+
+#, c-format
+msgid "%sError in expression to evaluate"
+msgstr "%sErreur dans l'expression à évaluer"
+
 #, c-format
 msgid "  %s[%s%s%s]%s buffer: %s%s%s / tags: %s / regex: %s %s"
 msgstr "  %s[%s%s%s]%s tampon: %s%s%s / tags: %s / regex: %s %s"
@@ -838,15 +845,15 @@ msgid "manage bars"
 msgstr "gestion des barres"
 
 msgid ""
-"list|listfull|listitems || add <name> <type>[,<cond1>[,<cond2>...]] "
-"<position> <size> <separator> <item1>[,<item2>...] || default [input|title|"
-"status|nicklist] || del <name>|-all || set <name> <option> <value> || hide|"
-"show|toggle <name> || scroll <name> <window> <scroll_value>"
+"list|listfull|listitems || add <name> <type>[,<condition>] <position> <size> "
+"<separator> <item1>[,<item2>...] || default [input|title|status|nicklist] || "
+"del <name>|-all || set <name> <option> <value> || hide|show|toggle <name> || "
+"scroll <name> <window> <scroll_value>"
 msgstr ""
-"list|listfull|listitems || add <nom> <type>[,<cond1>[,<cond2>...]] "
-"<position> <taille> <séparateur> <objet1>[,<objet2>...] || default [input|"
-"title|status|nicklist] || del <nom>|-all || set <nom> <option> <valeur> || "
-"hide|show|toggle <nom> || scroll <nom> <fenêtre> <valeur_scroll>"
+"list|listfull|listitems || add <nom> <type>[,<conditions>] <position> "
+"<taille> <séparateur> <objet1>[,<objet2>...] || default [input|title|status|"
+"nicklist] || del <nom>|-all || set <nom> <option> <valeur> || hide|show|"
+"toggle <nom> || scroll <nom> <fenêtre> <valeur_scroll>"
 
 msgid ""
 "         list: list all bars\n"
@@ -856,11 +863,13 @@ msgid ""
 "         name: name of bar (must be unique)\n"
 "         type:   root: outside windows,\n"
 "               window: inside windows, with optional conditions (see below)\n"
-"    cond1,...: condition(s) for displaying bar (only for type \"window\"):\n"
+"    condition: condition(s) for displaying bar (only for type \"window\"):\n"
 "                 active: on active window\n"
 "               inactive: on inactive windows\n"
 "               nicklist: on windows with nicklist\n"
-"               without condition, bar is always displayed\n"
+"               other condition: see /help weechat.bar.xxx.conditions and /"
+"help eval\n"
+"               without condition, the bar is always displayed\n"
 "     position: bottom, top, left or right\n"
 "         size: size of bar (in chars)\n"
 "    separator: 1 for using separator (line), 0 or nothing means no "
@@ -902,11 +911,13 @@ msgstr ""
 "         type:   root: en dehors des fenêtres\n"
 "               window: dans les fenêtres, avec condition(s) optionnelle(s) "
 "(voir ci-dessous)\n"
-"    cond1,...: condition(s) pour afficher cette barre (seulement pour le "
+"    condition: condition(s) pour afficher cette barre (seulement pour le "
 "type \"window\"):\n"
 "                 active: sur la fenêtre active\n"
 "               inactive: sur les fenêtres inactives\n"
 "               nicklist: sur les fenêtres avec liste de pseudos\n"
+"               autre condition: voir /help weechat.bar.xxx.conditions et /"
+"help eval\n"
 "               sans condition, la barre est toujours affichée\n"
 "     position: bottom (bas), top (haut), left (gauche) ou right (droite)\n"
 "       taille: taille de la barre (en caractères)\n"
@@ -1216,6 +1227,130 @@ msgstr ""
 "     term: afficher des infos sur le terminal\n"
 "  windows: afficher l'arbre des fenêtres"
 
+msgid "evaluate expression and send result to buffer"
+msgstr "évaluer une expression et envoyer le résultat au tampon"
+
+msgid "[-n] <expression> || [-n] <expression1> <operator> <expression2>"
+msgstr "[-n] <expression> || [-n] <expression1> <opérateur> <expression2>"
+
+msgid ""
+"        -n: display result without sending it to buffer (debug mode)\n"
+"expression: expression to evaluate, variables with format ${variable} are "
+"replaced (see below)\n"
+"  operator: a logical or comparison operator:\n"
+"            - logical operators:\n"
+"                &&  boolean \"and\"\n"
+"                ||  boolean \"or\"\n"
+"            - comparison operators:\n"
+"                ==  equal\n"
+"                !=  not equal\n"
+"                <=  less or equal\n"
+"                <   less\n"
+"                >=  greater or equal\n"
+"                >   greater\n"
+"                =~  is matching regex\n"
+"                !~  is NOT matching regex\n"
+"\n"
+"An expression is considered as \"true\" if it is not NULL, not empty, and "
+"different from \"0\".\n"
+"The comparison is made using integers if the two expressions are valid "
+"integers.\n"
+"To force a string comparison, add double quotes around each expression, for "
+"example:\n"
+"  50 > 100      ==> 0\n"
+"  \"50\" > \"100\"  ==> 1\n"
+"\n"
+"Some variables are replaced in expression, using the format ${variable}, "
+"variable can be, by order of prioity :\n"
+"  1. the name of an option (file.section.option)\n"
+"  2. a hdata name/variable (the value is automatically converted to string), "
+"by default \"window\" and \"buffer\" point to current window/buffer.\n"
+"Format for hdata can be one of following:\n"
+"  hdata.var1.var2...: start with a hdata (pointer must be known), and ask "
+"variables one after one (other hdata can be followed)\n"
+"  hdata(list).var1.var2...: start with a hdata using a list, for example:\n"
+"    ${buffer[gui_buffers].full_name}: full name of first buffer in linked "
+"list of buffers\n"
+"    ${plugin[weechat_plugins].name}: name of first plugin in linked list of "
+"plugins\n"
+"For name of hdata and variables, please look at \"Plugin API reference\", "
+"function \"weechat_hdata_get\".\n"
+"\n"
+"Examples:\n"
+"  /eval -n ${weechat.look.scroll_amount}  ==> 3\n"
+"  /eval -n ${window}                      ==> 0x2549aa0\n"
+"  /eval -n ${window.buffer}               ==> 0x2549320\n"
+"  /eval -n ${window.buffer.full_name}     ==> core.weechat\n"
+"  /eval -n ${window.buffer.number}        ==> 1\n"
+"  /eval -n ${window.buffer.number} > 2    ==> 0\n"
+"  /eval -n ${window.win_width} > 100      ==> 1\n"
+"  /eval -n (8 > 12) || (5 > 2)            ==> 1\n"
+"  /eval -n (8 > 12) && (5 > 2)            ==> 0\n"
+"  /eval -n abcd =~ ^ABC                   ==> 1\n"
+"  /eval -n abcd =~ (?-i)^ABC              ==> 0\n"
+"  /eval -n abcd =~ (?-i)^abc              ==> 1\n"
+"  /eval -n abcd !~ abc                    ==> 0"
+msgstr ""
+"        -n: afficher le résultat sans envoyer au tampon (mode debug)\n"
+"expression: expression à évaluer, les variables avec le format ${variable} "
+"sont remplacées (voir ci-dessous)\n"
+" opérateur: un opérateur logique ou de comparaison :\n"
+"            - opérateurs logiques :\n"
+"                &&  \"et\" booléen\n"
+"                ||  \"ou\" booléen\n"
+"            - opérateurs de comparaison :\n"
+"                ==  égal\n"
+"                !=  non égal\n"
+"                <=  inférieur ou égal\n"
+"                <   inférieur\n"
+"                >=  supérieur ou égal\n"
+"                >   supérieur\n"
+"                =~  correspond à l'expression régulière\n"
+"                !~  ne correspond PAS à l'expression régulière\n"
+"\n"
+"Une expression est considérée comme \"vraie\" si elle est non NULL, non "
+"vide, et différente de \"0\".\n"
+"La comparaison est faite en utilisant des entiers si les deux expressions "
+"sont des entiers valides.\n"
+"Pour forcer une comparaison de chaînes, ajoutez des guillemets autour de "
+"chaque expression, par exemple :\n"
+"  50 > 100      ==> 0\n"
+"  \"50\" > \"100\"  ==> 1\n"
+"\n"
+"Des variables sont remplacées dans l'expression, en utilisant le format "
+"${variable}, la variable pouvant être, par ordre de priorité :\n"
+"  1. le nom d'une option (fichier.section.option)\n"
+"  2. le nom d'un hdata/variable (la valeur est automatiquement convertie en "
+"chaîne), par défaut \"window\" et \"buffer\" pointent vers la fenêtre et le "
+"tampon courants.\n"
+"Le format du hdata peut être le suivant :\n"
+"  hdata.var1.var2...: démarrer avec un hdata (le pointeur doit être connu), "
+"et demander les variables l'une après l'autre (d'autres hdata peuvent être "
+"suivis)\n"
+"  hdata(list).var1.var2...: démarrer avec un hdata en utlisant une liste, "
+"par exemple :\n"
+"    ${buffer[gui_buffers].full_name}: nom complet du premier tampon dans la "
+"liste chaînée des tampons\n"
+"    ${plugin[weechat_plugins].name}: nom de la première extension dans la "
+"liste chaînée des extensions\n"
+"Pour le nom du hdata et des variables, voir la \"Référence API extension\", "
+"fonction \"weechat_hdata_get\".\n"
+"\n"
+"Exemples:\n"
+"  /eval -n ${weechat.look.scroll_amount}  ==> 3\n"
+"  /eval -n ${window}                      ==> 0x2549aa0\n"
+"  /eval -n ${window.buffer}               ==> 0x2549320\n"
+"  /eval -n ${window.buffer.full_name}     ==> core.weechat\n"
+"  /eval -n ${window.buffer.number}        ==> 1\n"
+"  /eval -n ${window.buffer.number} > 2    ==> 0\n"
+"  /eval -n ${window.win_width} > 100      ==> 1\n"
+"  /eval -n (8 > 12) || (5 > 2)            ==> 1\n"
+"  /eval -n (8 > 12) && (5 > 2)            ==> 0\n"
+"  /eval -n abcd =~ ^ABC                   ==> 1\n"
+"  /eval -n abcd =~ (?-i)^ABC              ==> 0\n"
+"  /eval -n abcd =~ (?-i)^abc              ==> 1\n"
+"  /eval -n abcd !~ abc                    ==> 0"
+
 msgid ""
 "filter messages in buffers, to hide/show them according to tags or regex"
 msgstr ""
@@ -2365,6 +2500,11 @@ msgstr "alias pour la couleur"
 msgid "%sError: palette option must be numeric"
 msgstr "%sErreur: l'option de palette doit être numérique"
 
+#, c-format
+msgid "%sWarning: unknown option for section \"%s\": %s (value: \"%s\")"
+msgstr ""
+"%sAttention: option inconnue pour la section \"%s\": %s (valeur: \"%s\")"
+
 msgid "Notify level for buffer"
 msgstr "Niveau de notification pour le tampon"
 
@@ -3617,13 +3757,18 @@ msgid "bar type (root, window, window_active, window_inactive)"
 msgstr "type de barre (root, window, window_active, window_inactive)"
 
 msgid ""
-"condition(s) for displaying bar (for bars of type \"window\"): \"active\" = "
-"window must be active, \"inactive\" = window must be inactive, \"nicklist\" "
-"= buffer must have a nicklist"
+"condition(s) for displaying bar (for bars of type \"window\"): a simple "
+"condition: \"active\", \"inactive\", \"nicklist\" (window must be active/"
+"inactive, buffer must have a nicklist), or an expression with condition(s) "
+"(see /help eval), like: \"${nicklist} && ${window.win_width} > 100\" (local "
+"variables for expression are ${active}, ${inactive} and ${nicklist})"
 msgstr ""
 "condition(s) pour afficher la barre (pour les barres de type \"window\"): "
-"\"active\" = la fenêtre doit être active, \"inactive\" = la fenêtre doit "
-"être inactive, \"nicklist\" = le tampon doit avoir une liste de pseudos"
+"une simple condition: \"active\", \"inactive\", \"nicklist\" (la fenêtre "
+"doit être active/inactive, le tampon doit avoir une liste de pseudos), ou "
+"une expression avec condition(s) (voir /help eval), comme: \"${nicklist} && "
+"${window.win_width} > 100\" (les variables locales pour l'expression sont "
+"${active}, ${inactive} et ${nicklist})"
 
 msgid "bar position (bottom, top, left, right)"
 msgstr ""
@@ -9612,6 +9757,15 @@ msgstr "Type"
 msgid "Constants"
 msgstr "Constantes"
 
+#~ msgid ""
+#~ "condition(s) for displaying bar (for bars of type \"window\"): \"active\" "
+#~ "= window must be active, \"inactive\" = window must be inactive, "
+#~ "\"nicklist\" = buffer must have a nicklist"
+#~ msgstr ""
+#~ "condition(s) pour afficher la barre (pour les barres de type \"window\"): "
+#~ "\"active\" = la fenêtre doit être active, \"inactive\" = la fenêtre doit "
+#~ "être inactive, \"nicklist\" = le tampon doit avoir une liste de pseudos"
+
 #~ msgid ""
 #~ "server: server name\n"
 #~ "  nick: nick (may be a mask)"
diff --git a/po/hu.po b/po/hu.po
index d895a5f03..20a95a5ce 100644
--- a/po/hu.po
+++ b/po/hu.po
@@ -20,7 +20,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat 0.4.0-dev\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2012-10-20 17:54+0200\n"
+"POT-Creation-Date: 2012-11-02 08:59+0100\n"
 "PO-Revision-Date: 2012-09-29 11:42+0200\n"
 "Last-Translator: Andras Voroskoi <voroskoi@frugalware.org>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -250,6 +250,13 @@ msgstr ""
 msgid "Debug disabled for \"%s\""
 msgstr ""
 
+msgid "error"
+msgstr ""
+
+#, c-format
+msgid "%sError in expression to evaluate"
+msgstr ""
+
 #, fuzzy, c-format
 msgid "  %s[%s%s%s]%s buffer: %s%s%s / tags: %s / regex: %s %s"
 msgstr "       (nincs üzenetkezelő)\n"
@@ -873,10 +880,10 @@ msgid "manage bars"
 msgstr "pufferek kezelése"
 
 msgid ""
-"list|listfull|listitems || add <name> <type>[,<cond1>[,<cond2>...]] "
-"<position> <size> <separator> <item1>[,<item2>...] || default [input|title|"
-"status|nicklist] || del <name>|-all || set <name> <option> <value> || hide|"
-"show|toggle <name> || scroll <name> <window> <scroll_value>"
+"list|listfull|listitems || add <name> <type>[,<condition>] <position> <size> "
+"<separator> <item1>[,<item2>...] || default [input|title|status|nicklist] || "
+"del <name>|-all || set <name> <option> <value> || hide|show|toggle <name> || "
+"scroll <name> <window> <scroll_value>"
 msgstr ""
 
 msgid ""
@@ -887,11 +894,13 @@ msgid ""
 "         name: name of bar (must be unique)\n"
 "         type:   root: outside windows,\n"
 "               window: inside windows, with optional conditions (see below)\n"
-"    cond1,...: condition(s) for displaying bar (only for type \"window\"):\n"
+"    condition: condition(s) for displaying bar (only for type \"window\"):\n"
 "                 active: on active window\n"
 "               inactive: on inactive windows\n"
 "               nicklist: on windows with nicklist\n"
-"               without condition, bar is always displayed\n"
+"               other condition: see /help weechat.bar.xxx.conditions and /"
+"help eval\n"
+"               without condition, the bar is always displayed\n"
 "     position: bottom, top, left or right\n"
 "         size: size of bar (in chars)\n"
 "    separator: 1 for using separator (line), 0 or nothing means no "
@@ -1120,6 +1129,71 @@ msgstr ""
 " buffer: hexadecimális puffertartalom logba írása\n"
 "windows: ablakfa megjelenítése"
 
+msgid "evaluate expression and send result to buffer"
+msgstr ""
+
+msgid "[-n] <expression> || [-n] <expression1> <operator> <expression2>"
+msgstr ""
+
+msgid ""
+"        -n: display result without sending it to buffer (debug mode)\n"
+"expression: expression to evaluate, variables with format ${variable} are "
+"replaced (see below)\n"
+"  operator: a logical or comparison operator:\n"
+"            - logical operators:\n"
+"                &&  boolean \"and\"\n"
+"                ||  boolean \"or\"\n"
+"            - comparison operators:\n"
+"                ==  equal\n"
+"                !=  not equal\n"
+"                <=  less or equal\n"
+"                <   less\n"
+"                >=  greater or equal\n"
+"                >   greater\n"
+"                =~  is matching regex\n"
+"                !~  is NOT matching regex\n"
+"\n"
+"An expression is considered as \"true\" if it is not NULL, not empty, and "
+"different from \"0\".\n"
+"The comparison is made using integers if the two expressions are valid "
+"integers.\n"
+"To force a string comparison, add double quotes around each expression, for "
+"example:\n"
+"  50 > 100      ==> 0\n"
+"  \"50\" > \"100\"  ==> 1\n"
+"\n"
+"Some variables are replaced in expression, using the format ${variable}, "
+"variable can be, by order of prioity :\n"
+"  1. the name of an option (file.section.option)\n"
+"  2. a hdata name/variable (the value is automatically converted to string), "
+"by default \"window\" and \"buffer\" point to current window/buffer.\n"
+"Format for hdata can be one of following:\n"
+"  hdata.var1.var2...: start with a hdata (pointer must be known), and ask "
+"variables one after one (other hdata can be followed)\n"
+"  hdata(list).var1.var2...: start with a hdata using a list, for example:\n"
+"    ${buffer[gui_buffers].full_name}: full name of first buffer in linked "
+"list of buffers\n"
+"    ${plugin[weechat_plugins].name}: name of first plugin in linked list of "
+"plugins\n"
+"For name of hdata and variables, please look at \"Plugin API reference\", "
+"function \"weechat_hdata_get\".\n"
+"\n"
+"Examples:\n"
+"  /eval -n ${weechat.look.scroll_amount}  ==> 3\n"
+"  /eval -n ${window}                      ==> 0x2549aa0\n"
+"  /eval -n ${window.buffer}               ==> 0x2549320\n"
+"  /eval -n ${window.buffer.full_name}     ==> core.weechat\n"
+"  /eval -n ${window.buffer.number}        ==> 1\n"
+"  /eval -n ${window.buffer.number} > 2    ==> 0\n"
+"  /eval -n ${window.win_width} > 100      ==> 1\n"
+"  /eval -n (8 > 12) || (5 > 2)            ==> 1\n"
+"  /eval -n (8 > 12) && (5 > 2)            ==> 0\n"
+"  /eval -n abcd =~ ^ABC                   ==> 1\n"
+"  /eval -n abcd =~ (?-i)^ABC              ==> 0\n"
+"  /eval -n abcd =~ (?-i)^abc              ==> 1\n"
+"  /eval -n abcd !~ abc                    ==> 0"
+msgstr ""
+
 msgid ""
 "filter messages in buffers, to hide/show them according to tags or regex"
 msgstr ""
@@ -1919,6 +1993,10 @@ msgstr ""
 msgid "%sError: palette option must be numeric"
 msgstr "%s nem sikerült a modul opciókat elmenteni\n"
 
+#, fuzzy, c-format
+msgid "%sWarning: unknown option for section \"%s\": %s (value: \"%s\")"
+msgstr "%s %s, %d. sor: ismeretlen csoportazonosító (\"%s\")\n"
+
 #, fuzzy
 msgid "Notify level for buffer"
 msgstr "szobanév nem található a pufferhez"
@@ -3029,9 +3107,11 @@ msgid "bar type (root, window, window_active, window_inactive)"
 msgstr ""
 
 msgid ""
-"condition(s) for displaying bar (for bars of type \"window\"): \"active\" = "
-"window must be active, \"inactive\" = window must be inactive, \"nicklist\" "
-"= buffer must have a nicklist"
+"condition(s) for displaying bar (for bars of type \"window\"): a simple "
+"condition: \"active\", \"inactive\", \"nicklist\" (window must be active/"
+"inactive, buffer must have a nicklist), or an expression with condition(s) "
+"(see /help eval), like: \"${nicklist} && ${window.win_width} > 100\" (local "
+"variables for expression are ${active}, ${inactive} and ${nicklist})"
 msgstr ""
 
 #, fuzzy
diff --git a/po/it.po b/po/it.po
index 515a0e6b1..bc3556fa3 100644
--- a/po/it.po
+++ b/po/it.po
@@ -20,7 +20,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat 0.4.0-dev\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2012-10-20 17:54+0200\n"
+"POT-Creation-Date: 2012-11-02 08:59+0100\n"
 "PO-Revision-Date: 2012-09-29 11:42+0200\n"
 "Last-Translator: Marco Paolone <marcopaolone@gmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -249,6 +249,13 @@ msgstr "Il contenuto raw dei buffer è stato salvato sul file di log"
 msgid "Debug disabled for \"%s\""
 msgstr "Debug disabilitato per \"%s\""
 
+msgid "error"
+msgstr ""
+
+#, c-format
+msgid "%sError in expression to evaluate"
+msgstr ""
+
 #, c-format
 msgid "  %s[%s%s%s]%s buffer: %s%s%s / tags: %s / regex: %s %s"
 msgstr "  %s[%s%s%s]%s buffer: %s%s%s / tag: %s /regex: %s %s"
@@ -831,17 +838,19 @@ msgstr ""
 msgid "manage bars"
 msgstr "gestione delle barre"
 
+#, fuzzy
 msgid ""
-"list|listfull|listitems || add <name> <type>[,<cond1>[,<cond2>...]] "
-"<position> <size> <separator> <item1>[,<item2>...] || default [input|title|"
-"status|nicklist] || del <name>|-all || set <name> <option> <value> || hide|"
-"show|toggle <name> || scroll <name> <window> <scroll_value>"
+"list|listfull|listitems || add <name> <type>[,<condition>] <position> <size> "
+"<separator> <item1>[,<item2>...] || default [input|title|status|nicklist] || "
+"del <name>|-all || set <name> <option> <value> || hide|show|toggle <name> || "
+"scroll <name> <window> <scroll_value>"
 msgstr ""
 "list|listfull|listitems || add <nome> <tipo>[,<cond1>[,<cond2>...]] "
 "<posizione> <dimensione> <separatore> <item1>[,<item2>...] || default [input|"
 "title|status|nicklist] || del <nome>|-all || set <nome> <opzione> <valore> "
 "|| hide|show|toggle <nome> || scroll <nome> <finestra> <scroll_value>"
 
+#, fuzzy
 msgid ""
 "         list: list all bars\n"
 "     listfull: list all bars (verbose)\n"
@@ -850,11 +859,13 @@ msgid ""
 "         name: name of bar (must be unique)\n"
 "         type:   root: outside windows,\n"
 "               window: inside windows, with optional conditions (see below)\n"
-"    cond1,...: condition(s) for displaying bar (only for type \"window\"):\n"
+"    condition: condition(s) for displaying bar (only for type \"window\"):\n"
 "                 active: on active window\n"
 "               inactive: on inactive windows\n"
 "               nicklist: on windows with nicklist\n"
-"               without condition, bar is always displayed\n"
+"               other condition: see /help weechat.bar.xxx.conditions and /"
+"help eval\n"
+"               without condition, the bar is always displayed\n"
 "     position: bottom, top, left or right\n"
 "         size: size of bar (in chars)\n"
 "    separator: 1 for using separator (line), 0 or nothing means no "
@@ -1205,6 +1216,71 @@ msgstr ""
 "     term: mostra informazioni sul terminale\n"
 "  windows: mostra l'albero delle finestre"
 
+msgid "evaluate expression and send result to buffer"
+msgstr ""
+
+msgid "[-n] <expression> || [-n] <expression1> <operator> <expression2>"
+msgstr ""
+
+msgid ""
+"        -n: display result without sending it to buffer (debug mode)\n"
+"expression: expression to evaluate, variables with format ${variable} are "
+"replaced (see below)\n"
+"  operator: a logical or comparison operator:\n"
+"            - logical operators:\n"
+"                &&  boolean \"and\"\n"
+"                ||  boolean \"or\"\n"
+"            - comparison operators:\n"
+"                ==  equal\n"
+"                !=  not equal\n"
+"                <=  less or equal\n"
+"                <   less\n"
+"                >=  greater or equal\n"
+"                >   greater\n"
+"                =~  is matching regex\n"
+"                !~  is NOT matching regex\n"
+"\n"
+"An expression is considered as \"true\" if it is not NULL, not empty, and "
+"different from \"0\".\n"
+"The comparison is made using integers if the two expressions are valid "
+"integers.\n"
+"To force a string comparison, add double quotes around each expression, for "
+"example:\n"
+"  50 > 100      ==> 0\n"
+"  \"50\" > \"100\"  ==> 1\n"
+"\n"
+"Some variables are replaced in expression, using the format ${variable}, "
+"variable can be, by order of prioity :\n"
+"  1. the name of an option (file.section.option)\n"
+"  2. a hdata name/variable (the value is automatically converted to string), "
+"by default \"window\" and \"buffer\" point to current window/buffer.\n"
+"Format for hdata can be one of following:\n"
+"  hdata.var1.var2...: start with a hdata (pointer must be known), and ask "
+"variables one after one (other hdata can be followed)\n"
+"  hdata(list).var1.var2...: start with a hdata using a list, for example:\n"
+"    ${buffer[gui_buffers].full_name}: full name of first buffer in linked "
+"list of buffers\n"
+"    ${plugin[weechat_plugins].name}: name of first plugin in linked list of "
+"plugins\n"
+"For name of hdata and variables, please look at \"Plugin API reference\", "
+"function \"weechat_hdata_get\".\n"
+"\n"
+"Examples:\n"
+"  /eval -n ${weechat.look.scroll_amount}  ==> 3\n"
+"  /eval -n ${window}                      ==> 0x2549aa0\n"
+"  /eval -n ${window.buffer}               ==> 0x2549320\n"
+"  /eval -n ${window.buffer.full_name}     ==> core.weechat\n"
+"  /eval -n ${window.buffer.number}        ==> 1\n"
+"  /eval -n ${window.buffer.number} > 2    ==> 0\n"
+"  /eval -n ${window.win_width} > 100      ==> 1\n"
+"  /eval -n (8 > 12) || (5 > 2)            ==> 1\n"
+"  /eval -n (8 > 12) && (5 > 2)            ==> 0\n"
+"  /eval -n abcd =~ ^ABC                   ==> 1\n"
+"  /eval -n abcd =~ (?-i)^ABC              ==> 0\n"
+"  /eval -n abcd =~ (?-i)^abc              ==> 1\n"
+"  /eval -n abcd !~ abc                    ==> 0"
+msgstr ""
+
 msgid ""
 "filter messages in buffers, to hide/show them according to tags or regex"
 msgstr ""
@@ -2334,6 +2410,11 @@ msgstr "alias per il colore"
 msgid "%sError: palette option must be numeric"
 msgstr "%sErrore: l'opzione per la tavolozza deve essere numerica"
 
+#, fuzzy, c-format
+msgid "%sWarning: unknown option for section \"%s\": %s (value: \"%s\")"
+msgstr ""
+"%sAttenzione: %s, riga %d: opzione sconosciuta per la sezione \"%s\": %s"
+
 msgid "Notify level for buffer"
 msgstr "Livello di notifica per il buffer"
 
@@ -3543,13 +3624,12 @@ msgid "bar type (root, window, window_active, window_inactive)"
 msgstr "tipo di barra (root, window, window_active, window_inactive)"
 
 msgid ""
-"condition(s) for displaying bar (for bars of type \"window\"): \"active\" = "
-"window must be active, \"inactive\" = window must be inactive, \"nicklist\" "
-"= buffer must have a nicklist"
+"condition(s) for displaying bar (for bars of type \"window\"): a simple "
+"condition: \"active\", \"inactive\", \"nicklist\" (window must be active/"
+"inactive, buffer must have a nicklist), or an expression with condition(s) "
+"(see /help eval), like: \"${nicklist} && ${window.win_width} > 100\" (local "
+"variables for expression are ${active}, ${inactive} and ${nicklist})"
 msgstr ""
-"condizioni per mostrare la barra (per le barre di tipo \"window\"): \"active"
-"\"= la finestra deve essere attiva, \"inactive\" = la finestra deve essere "
-"inattiva, \"nicklist\" = il buffer deve avere una lista nick"
 
 msgid "bar position (bottom, top, left, right)"
 msgstr ""
@@ -9389,6 +9469,15 @@ msgstr "Tipo"
 msgid "Constants"
 msgstr "Costanti"
 
+#~ msgid ""
+#~ "condition(s) for displaying bar (for bars of type \"window\"): \"active\" "
+#~ "= window must be active, \"inactive\" = window must be inactive, "
+#~ "\"nicklist\" = buffer must have a nicklist"
+#~ msgstr ""
+#~ "condizioni per mostrare la barra (per le barre di tipo \"window\"): "
+#~ "\"active\"= la finestra deve essere attiva, \"inactive\" = la finestra "
+#~ "deve essere inattiva, \"nicklist\" = il buffer deve avere una lista nick"
+
 #~ msgid ""
 #~ "server: server name\n"
 #~ "  nick: nick (may be a mask)"
diff --git a/po/ja.po b/po/ja.po
index b13cd0789..d13a6f67c 100644
--- a/po/ja.po
+++ b/po/ja.po
@@ -20,7 +20,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat 0.4.0-dev\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2012-10-20 17:54+0200\n"
+"POT-Creation-Date: 2012-11-02 08:59+0100\n"
 "PO-Revision-Date: 2012-09-29 11:42+0200\n"
 "Last-Translator: AYANOKOUZI, Ryuunosuke <i38w7i3@yahoo.co.jp>\n"
 "Language-Team: Japanese <https://github.com/l/WeeChat>\n"
@@ -249,6 +249,13 @@ msgstr "バッファの生データがログファイルに書き込まれまし
 msgid "Debug disabled for \"%s\""
 msgstr "\"%s\" に対するデバッグが無効になりました"
 
+msgid "error"
+msgstr ""
+
+#, c-format
+msgid "%sError in expression to evaluate"
+msgstr ""
+
 #, c-format
 msgid "  %s[%s%s%s]%s buffer: %s%s%s / tags: %s / regex: %s %s"
 msgstr "  %s[%s%s%s]%s バッファ: %s%s%s / タグ: %s / 正規表現: %s %s"
@@ -825,17 +832,19 @@ msgstr ""
 msgid "manage bars"
 msgstr "バーの管理"
 
+#, fuzzy
 msgid ""
-"list|listfull|listitems || add <name> <type>[,<cond1>[,<cond2>...]] "
-"<position> <size> <separator> <item1>[,<item2>...] || default [input|title|"
-"status|nicklist] || del <name>|-all || set <name> <option> <value> || hide|"
-"show|toggle <name> || scroll <name> <window> <scroll_value>"
+"list|listfull|listitems || add <name> <type>[,<condition>] <position> <size> "
+"<separator> <item1>[,<item2>...] || default [input|title|status|nicklist] || "
+"del <name>|-all || set <name> <option> <value> || hide|show|toggle <name> || "
+"scroll <name> <window> <scroll_value>"
 msgstr ""
 "list|listfull|listitems || add <name> <type>[,<cond1>[,<cond2>...]] "
 "<position> <size> <separator> <item1>[,<item2>...] || default [input|title|"
 "status|nicklist] || del <name>|-all || set <name> <option> <value> || hide|"
 "show|toggle <name> || scroll <name> <window> <scroll_value>"
 
+#, fuzzy
 msgid ""
 "         list: list all bars\n"
 "     listfull: list all bars (verbose)\n"
@@ -844,11 +853,13 @@ msgid ""
 "         name: name of bar (must be unique)\n"
 "         type:   root: outside windows,\n"
 "               window: inside windows, with optional conditions (see below)\n"
-"    cond1,...: condition(s) for displaying bar (only for type \"window\"):\n"
+"    condition: condition(s) for displaying bar (only for type \"window\"):\n"
 "                 active: on active window\n"
 "               inactive: on inactive windows\n"
 "               nicklist: on windows with nicklist\n"
-"               without condition, bar is always displayed\n"
+"               other condition: see /help weechat.bar.xxx.conditions and /"
+"help eval\n"
+"               without condition, the bar is always displayed\n"
 "     position: bottom, top, left or right\n"
 "         size: size of bar (in chars)\n"
 "    separator: 1 for using separator (line), 0 or nothing means no "
@@ -1191,6 +1202,71 @@ msgstr ""
 "     term: ターミナルに関する情報を表示\n"
 "  windows: ウィンドウツリーの情報を表示"
 
+msgid "evaluate expression and send result to buffer"
+msgstr ""
+
+msgid "[-n] <expression> || [-n] <expression1> <operator> <expression2>"
+msgstr ""
+
+msgid ""
+"        -n: display result without sending it to buffer (debug mode)\n"
+"expression: expression to evaluate, variables with format ${variable} are "
+"replaced (see below)\n"
+"  operator: a logical or comparison operator:\n"
+"            - logical operators:\n"
+"                &&  boolean \"and\"\n"
+"                ||  boolean \"or\"\n"
+"            - comparison operators:\n"
+"                ==  equal\n"
+"                !=  not equal\n"
+"                <=  less or equal\n"
+"                <   less\n"
+"                >=  greater or equal\n"
+"                >   greater\n"
+"                =~  is matching regex\n"
+"                !~  is NOT matching regex\n"
+"\n"
+"An expression is considered as \"true\" if it is not NULL, not empty, and "
+"different from \"0\".\n"
+"The comparison is made using integers if the two expressions are valid "
+"integers.\n"
+"To force a string comparison, add double quotes around each expression, for "
+"example:\n"
+"  50 > 100      ==> 0\n"
+"  \"50\" > \"100\"  ==> 1\n"
+"\n"
+"Some variables are replaced in expression, using the format ${variable}, "
+"variable can be, by order of prioity :\n"
+"  1. the name of an option (file.section.option)\n"
+"  2. a hdata name/variable (the value is automatically converted to string), "
+"by default \"window\" and \"buffer\" point to current window/buffer.\n"
+"Format for hdata can be one of following:\n"
+"  hdata.var1.var2...: start with a hdata (pointer must be known), and ask "
+"variables one after one (other hdata can be followed)\n"
+"  hdata(list).var1.var2...: start with a hdata using a list, for example:\n"
+"    ${buffer[gui_buffers].full_name}: full name of first buffer in linked "
+"list of buffers\n"
+"    ${plugin[weechat_plugins].name}: name of first plugin in linked list of "
+"plugins\n"
+"For name of hdata and variables, please look at \"Plugin API reference\", "
+"function \"weechat_hdata_get\".\n"
+"\n"
+"Examples:\n"
+"  /eval -n ${weechat.look.scroll_amount}  ==> 3\n"
+"  /eval -n ${window}                      ==> 0x2549aa0\n"
+"  /eval -n ${window.buffer}               ==> 0x2549320\n"
+"  /eval -n ${window.buffer.full_name}     ==> core.weechat\n"
+"  /eval -n ${window.buffer.number}        ==> 1\n"
+"  /eval -n ${window.buffer.number} > 2    ==> 0\n"
+"  /eval -n ${window.win_width} > 100      ==> 1\n"
+"  /eval -n (8 > 12) || (5 > 2)            ==> 1\n"
+"  /eval -n (8 > 12) && (5 > 2)            ==> 0\n"
+"  /eval -n abcd =~ ^ABC                   ==> 1\n"
+"  /eval -n abcd =~ (?-i)^ABC              ==> 0\n"
+"  /eval -n abcd =~ (?-i)^abc              ==> 1\n"
+"  /eval -n abcd !~ abc                    ==> 0"
+msgstr ""
+
 msgid ""
 "filter messages in buffers, to hide/show them according to tags or regex"
 msgstr "タグか正規表現に基づくバッファメッセージの非表示/表示"
@@ -2302,6 +2378,10 @@ msgstr "色の別名"
 msgid "%sError: palette option must be numeric"
 msgstr "%sエラー: パレットオプションは数字でなければいけません"
 
+#, fuzzy, c-format
+msgid "%sWarning: unknown option for section \"%s\": %s (value: \"%s\")"
+msgstr "%s警告: %s、行 %d: セクション \"%s\" の無効なオプション: %s"
+
 msgid "Notify level for buffer"
 msgstr "バッファの通知レベル"
 
@@ -3466,13 +3546,12 @@ msgid "bar type (root, window, window_active, window_inactive)"
 msgstr "バー型 (root、window、window_active、window_inactive)"
 
 msgid ""
-"condition(s) for displaying bar (for bars of type \"window\"): \"active\" = "
-"window must be active, \"inactive\" = window must be inactive, \"nicklist\" "
-"= buffer must have a nicklist"
+"condition(s) for displaying bar (for bars of type \"window\"): a simple "
+"condition: \"active\", \"inactive\", \"nicklist\" (window must be active/"
+"inactive, buffer must have a nicklist), or an expression with condition(s) "
+"(see /help eval), like: \"${nicklist} && ${window.win_width} > 100\" (local "
+"variables for expression are ${active}, ${inactive} and ${nicklist})"
 msgstr ""
-"バー表示状態 (\"window\" 型のバー): \"active\" = ウィンドウはアクティブ状"
-"態、\"inactive\" = ウィンドウはインアクティブ状態、\"nicklist\" = バッファは"
-"ニックネームリストを持つ"
 
 msgid "bar position (bottom, top, left, right)"
 msgstr "バー位置 (下、上、左、右)"
@@ -9257,6 +9336,15 @@ msgstr "タイプ"
 msgid "Constants"
 msgstr "定数"
 
+#~ msgid ""
+#~ "condition(s) for displaying bar (for bars of type \"window\"): \"active\" "
+#~ "= window must be active, \"inactive\" = window must be inactive, "
+#~ "\"nicklist\" = buffer must have a nicklist"
+#~ msgstr ""
+#~ "バー表示状態 (\"window\" 型のバー): \"active\" = ウィンドウはアクティブ状"
+#~ "態、\"inactive\" = ウィンドウはインアクティブ状態、\"nicklist\" = バッファ"
+#~ "はニックネームリストを持つ"
+
 #~ msgid ""
 #~ "server: server name\n"
 #~ "  nick: nick (may be a mask)"
diff --git a/po/pl.po b/po/pl.po
index 05d959c11..df21e7917 100644
--- a/po/pl.po
+++ b/po/pl.po
@@ -21,7 +21,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat 0.4.0-dev\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2012-10-20 17:54+0200\n"
+"POT-Creation-Date: 2012-11-02 08:59+0100\n"
 "PO-Revision-Date: 2012-09-29 11:42+0200\n"
 "Last-Translator: Krzysztof Korościk <soltys@szluug.org>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -251,6 +251,13 @@ msgstr "Surowa zawartość bufora została zapisana do pliku z logiem"
 msgid "Debug disabled for \"%s\""
 msgstr "Debugowanie wyłączone dla\"%s\""
 
+msgid "error"
+msgstr ""
+
+#, c-format
+msgid "%sError in expression to evaluate"
+msgstr ""
+
 #, c-format
 msgid "  %s[%s%s%s]%s buffer: %s%s%s / tags: %s / regex: %s %s"
 msgstr "  %s[%s%s%s]%s bufor: %s%s%s / tagi: %s / wyrażenie: %s %s"
@@ -844,17 +851,19 @@ msgstr ""
 msgid "manage bars"
 msgstr "zarządzaj paskami"
 
+#, fuzzy
 msgid ""
-"list|listfull|listitems || add <name> <type>[,<cond1>[,<cond2>...]] "
-"<position> <size> <separator> <item1>[,<item2>...] || default [input|title|"
-"status|nicklist] || del <name>|-all || set <name> <option> <value> || hide|"
-"show|toggle <name> || scroll <name> <window> <scroll_value>"
+"list|listfull|listitems || add <name> <type>[,<condition>] <position> <size> "
+"<separator> <item1>[,<item2>...] || default [input|title|status|nicklist] || "
+"del <name>|-all || set <name> <option> <value> || hide|show|toggle <name> || "
+"scroll <name> <window> <scroll_value>"
 msgstr ""
 "list|listfull|listitems || add <nazwa> <typ>[,<warunek1>[,<warunek2>...]] "
 "<pozycja> <rozmiar> <separator> <element1>[,<element2>...] || default [input|"
 "title|status|nicklist] || del <nazwa>|-all || set <nazwa> <opcja> <wartość> "
 "|| hide|show|toggle <nazwa> || scroll <nazwa> <okno> <wartość_przewinięcia>"
 
+#, fuzzy
 msgid ""
 "         list: list all bars\n"
 "     listfull: list all bars (verbose)\n"
@@ -863,11 +872,13 @@ msgid ""
 "         name: name of bar (must be unique)\n"
 "         type:   root: outside windows,\n"
 "               window: inside windows, with optional conditions (see below)\n"
-"    cond1,...: condition(s) for displaying bar (only for type \"window\"):\n"
+"    condition: condition(s) for displaying bar (only for type \"window\"):\n"
 "                 active: on active window\n"
 "               inactive: on inactive windows\n"
 "               nicklist: on windows with nicklist\n"
-"               without condition, bar is always displayed\n"
+"               other condition: see /help weechat.bar.xxx.conditions and /"
+"help eval\n"
+"               without condition, the bar is always displayed\n"
 "     position: bottom, top, left or right\n"
 "         size: size of bar (in chars)\n"
 "    separator: 1 for using separator (line), 0 or nothing means no "
@@ -1212,6 +1223,71 @@ msgstr ""
 "     term: wyświetla informacje o terminalu\n"
 "  windows: wyświetla drzewo okien"
 
+msgid "evaluate expression and send result to buffer"
+msgstr ""
+
+msgid "[-n] <expression> || [-n] <expression1> <operator> <expression2>"
+msgstr ""
+
+msgid ""
+"        -n: display result without sending it to buffer (debug mode)\n"
+"expression: expression to evaluate, variables with format ${variable} are "
+"replaced (see below)\n"
+"  operator: a logical or comparison operator:\n"
+"            - logical operators:\n"
+"                &&  boolean \"and\"\n"
+"                ||  boolean \"or\"\n"
+"            - comparison operators:\n"
+"                ==  equal\n"
+"                !=  not equal\n"
+"                <=  less or equal\n"
+"                <   less\n"
+"                >=  greater or equal\n"
+"                >   greater\n"
+"                =~  is matching regex\n"
+"                !~  is NOT matching regex\n"
+"\n"
+"An expression is considered as \"true\" if it is not NULL, not empty, and "
+"different from \"0\".\n"
+"The comparison is made using integers if the two expressions are valid "
+"integers.\n"
+"To force a string comparison, add double quotes around each expression, for "
+"example:\n"
+"  50 > 100      ==> 0\n"
+"  \"50\" > \"100\"  ==> 1\n"
+"\n"
+"Some variables are replaced in expression, using the format ${variable}, "
+"variable can be, by order of prioity :\n"
+"  1. the name of an option (file.section.option)\n"
+"  2. a hdata name/variable (the value is automatically converted to string), "
+"by default \"window\" and \"buffer\" point to current window/buffer.\n"
+"Format for hdata can be one of following:\n"
+"  hdata.var1.var2...: start with a hdata (pointer must be known), and ask "
+"variables one after one (other hdata can be followed)\n"
+"  hdata(list).var1.var2...: start with a hdata using a list, for example:\n"
+"    ${buffer[gui_buffers].full_name}: full name of first buffer in linked "
+"list of buffers\n"
+"    ${plugin[weechat_plugins].name}: name of first plugin in linked list of "
+"plugins\n"
+"For name of hdata and variables, please look at \"Plugin API reference\", "
+"function \"weechat_hdata_get\".\n"
+"\n"
+"Examples:\n"
+"  /eval -n ${weechat.look.scroll_amount}  ==> 3\n"
+"  /eval -n ${window}                      ==> 0x2549aa0\n"
+"  /eval -n ${window.buffer}               ==> 0x2549320\n"
+"  /eval -n ${window.buffer.full_name}     ==> core.weechat\n"
+"  /eval -n ${window.buffer.number}        ==> 1\n"
+"  /eval -n ${window.buffer.number} > 2    ==> 0\n"
+"  /eval -n ${window.win_width} > 100      ==> 1\n"
+"  /eval -n (8 > 12) || (5 > 2)            ==> 1\n"
+"  /eval -n (8 > 12) && (5 > 2)            ==> 0\n"
+"  /eval -n abcd =~ ^ABC                   ==> 1\n"
+"  /eval -n abcd =~ (?-i)^ABC              ==> 0\n"
+"  /eval -n abcd =~ (?-i)^abc              ==> 1\n"
+"  /eval -n abcd !~ abc                    ==> 0"
+msgstr ""
+
 msgid ""
 "filter messages in buffers, to hide/show them according to tags or regex"
 msgstr ""
@@ -2341,6 +2417,10 @@ msgstr "alias dla kolorów"
 msgid "%sError: palette option must be numeric"
 msgstr "%sBłąd: opcja palety musi być numerem"
 
+#, fuzzy, c-format
+msgid "%sWarning: unknown option for section \"%s\": %s (value: \"%s\")"
+msgstr "%sOstrzeżenie: %s, linia %d: nieznana opcja dla sekcji \"%s\": %s"
+
 msgid "Notify level for buffer"
 msgstr "Poziom powiadomień dla buforu"
 
@@ -3540,13 +3620,12 @@ msgid "bar type (root, window, window_active, window_inactive)"
 msgstr "typ paska (root, window, window_active, window_inactive)"
 
 msgid ""
-"condition(s) for displaying bar (for bars of type \"window\"): \"active\" = "
-"window must be active, \"inactive\" = window must be inactive, \"nicklist\" "
-"= buffer must have a nicklist"
+"condition(s) for displaying bar (for bars of type \"window\"): a simple "
+"condition: \"active\", \"inactive\", \"nicklist\" (window must be active/"
+"inactive, buffer must have a nicklist), or an expression with condition(s) "
+"(see /help eval), like: \"${nicklist} && ${window.win_width} > 100\" (local "
+"variables for expression are ${active}, ${inactive} and ${nicklist})"
 msgstr ""
-"warunek(-ki) wyświetlania paska (dla pasków typu \"window\"): \"active\" = "
-"okno musi być aktywne, \"inactive\" = okno musi być nieaktywne, \"nicklist\" "
-"= bufor musi posiadać listę nicków"
 
 msgid "bar position (bottom, top, left, right)"
 msgstr "pozycja paska (bottom (dół), top (góra), left (lewo), right (prawo))"
@@ -9319,6 +9398,15 @@ msgstr "Typ"
 msgid "Constants"
 msgstr "Stałe"
 
+#~ msgid ""
+#~ "condition(s) for displaying bar (for bars of type \"window\"): \"active\" "
+#~ "= window must be active, \"inactive\" = window must be inactive, "
+#~ "\"nicklist\" = buffer must have a nicklist"
+#~ msgstr ""
+#~ "warunek(-ki) wyświetlania paska (dla pasków typu \"window\"): \"active\" "
+#~ "= okno musi być aktywne, \"inactive\" = okno musi być nieaktywne, "
+#~ "\"nicklist\" = bufor musi posiadać listę nicków"
+
 #~ msgid ""
 #~ "server: server name\n"
 #~ "  nick: nick (may be a mask)"
diff --git a/po/pt_BR.po b/po/pt_BR.po
index 37975e015..1c66c5ef6 100644
--- a/po/pt_BR.po
+++ b/po/pt_BR.po
@@ -21,7 +21,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat 0.4.0-dev\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2012-10-20 17:54+0200\n"
+"POT-Creation-Date: 2012-11-02 08:59+0100\n"
 "PO-Revision-Date: 2012-09-29 11:43+0200\n"
 "Last-Translator: Sergio Durigan Junior <sergiosdj@gmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -273,6 +273,13 @@ msgstr "Conteúdo bruto dos buffers foi escrito no arquivo de log"
 msgid "Debug disabled for \"%s\""
 msgstr "Depuração desabilitada para \"%s\""
 
+msgid "error"
+msgstr ""
+
+#, c-format
+msgid "%sError in expression to evaluate"
+msgstr ""
+
 #, c-format
 msgid "  %s[%s%s%s]%s buffer: %s%s%s / tags: %s / regex: %s %s"
 msgstr ""
@@ -868,11 +875,12 @@ msgstr ""
 msgid "manage bars"
 msgstr "gerenciar barras"
 
+#, fuzzy
 msgid ""
-"list|listfull|listitems || add <name> <type>[,<cond1>[,<cond2>...]] "
-"<position> <size> <separator> <item1>[,<item2>...] || default [input|title|"
-"status|nicklist] || del <name>|-all || set <name> <option> <value> || hide|"
-"show|toggle <name> || scroll <name> <window> <scroll_value>"
+"list|listfull|listitems || add <name> <type>[,<condition>] <position> <size> "
+"<separator> <item1>[,<item2>...] || default [input|title|status|nicklist] || "
+"del <name>|-all || set <name> <option> <value> || hide|show|toggle <name> || "
+"scroll <name> <window> <scroll_value>"
 msgstr ""
 "list|listfull|listitems || add <nome> <tipo>[,<cond1>[,<cond2>...]] "
 "<posição> <tamanho> <separador> <item1>[,<item2>...] || default [input|title|"
@@ -881,6 +889,7 @@ msgstr ""
 
 # in the option "position", the parameters must be passes in english, but the
 # options were translated (inside parentesis) to become clearer
+#, fuzzy
 msgid ""
 "         list: list all bars\n"
 "     listfull: list all bars (verbose)\n"
@@ -889,11 +898,13 @@ msgid ""
 "         name: name of bar (must be unique)\n"
 "         type:   root: outside windows,\n"
 "               window: inside windows, with optional conditions (see below)\n"
-"    cond1,...: condition(s) for displaying bar (only for type \"window\"):\n"
+"    condition: condition(s) for displaying bar (only for type \"window\"):\n"
 "                 active: on active window\n"
 "               inactive: on inactive windows\n"
 "               nicklist: on windows with nicklist\n"
-"               without condition, bar is always displayed\n"
+"               other condition: see /help weechat.bar.xxx.conditions and /"
+"help eval\n"
+"               without condition, the bar is always displayed\n"
 "     position: bottom, top, left or right\n"
 "         size: size of bar (in chars)\n"
 "    separator: 1 for using separator (line), 0 or nothing means no "
@@ -1247,6 +1258,71 @@ msgstr ""
 "     term: exibe informações sobre o terminal\n"
 "  windows: exibe árvore de janelas"
 
+msgid "evaluate expression and send result to buffer"
+msgstr ""
+
+msgid "[-n] <expression> || [-n] <expression1> <operator> <expression2>"
+msgstr ""
+
+msgid ""
+"        -n: display result without sending it to buffer (debug mode)\n"
+"expression: expression to evaluate, variables with format ${variable} are "
+"replaced (see below)\n"
+"  operator: a logical or comparison operator:\n"
+"            - logical operators:\n"
+"                &&  boolean \"and\"\n"
+"                ||  boolean \"or\"\n"
+"            - comparison operators:\n"
+"                ==  equal\n"
+"                !=  not equal\n"
+"                <=  less or equal\n"
+"                <   less\n"
+"                >=  greater or equal\n"
+"                >   greater\n"
+"                =~  is matching regex\n"
+"                !~  is NOT matching regex\n"
+"\n"
+"An expression is considered as \"true\" if it is not NULL, not empty, and "
+"different from \"0\".\n"
+"The comparison is made using integers if the two expressions are valid "
+"integers.\n"
+"To force a string comparison, add double quotes around each expression, for "
+"example:\n"
+"  50 > 100      ==> 0\n"
+"  \"50\" > \"100\"  ==> 1\n"
+"\n"
+"Some variables are replaced in expression, using the format ${variable}, "
+"variable can be, by order of prioity :\n"
+"  1. the name of an option (file.section.option)\n"
+"  2. a hdata name/variable (the value is automatically converted to string), "
+"by default \"window\" and \"buffer\" point to current window/buffer.\n"
+"Format for hdata can be one of following:\n"
+"  hdata.var1.var2...: start with a hdata (pointer must be known), and ask "
+"variables one after one (other hdata can be followed)\n"
+"  hdata(list).var1.var2...: start with a hdata using a list, for example:\n"
+"    ${buffer[gui_buffers].full_name}: full name of first buffer in linked "
+"list of buffers\n"
+"    ${plugin[weechat_plugins].name}: name of first plugin in linked list of "
+"plugins\n"
+"For name of hdata and variables, please look at \"Plugin API reference\", "
+"function \"weechat_hdata_get\".\n"
+"\n"
+"Examples:\n"
+"  /eval -n ${weechat.look.scroll_amount}  ==> 3\n"
+"  /eval -n ${window}                      ==> 0x2549aa0\n"
+"  /eval -n ${window.buffer}               ==> 0x2549320\n"
+"  /eval -n ${window.buffer.full_name}     ==> core.weechat\n"
+"  /eval -n ${window.buffer.number}        ==> 1\n"
+"  /eval -n ${window.buffer.number} > 2    ==> 0\n"
+"  /eval -n ${window.win_width} > 100      ==> 1\n"
+"  /eval -n (8 > 12) || (5 > 2)            ==> 1\n"
+"  /eval -n (8 > 12) && (5 > 2)            ==> 0\n"
+"  /eval -n abcd =~ ^ABC                   ==> 1\n"
+"  /eval -n abcd =~ (?-i)^ABC              ==> 0\n"
+"  /eval -n abcd =~ (?-i)^abc              ==> 1\n"
+"  /eval -n abcd !~ abc                    ==> 0"
+msgstr ""
+
 msgid ""
 "filter messages in buffers, to hide/show them according to tags or regex"
 msgstr ""
@@ -2299,6 +2375,10 @@ msgstr "apelido para cor"
 msgid "%sError: palette option must be numeric"
 msgstr "%sErro: opção da palheta deve ser numérica"
 
+#, fuzzy, c-format
+msgid "%sWarning: unknown option for section \"%s\": %s (value: \"%s\")"
+msgstr "%sAviso: %s, linha %d: opção \"%s\" desconhecido para seção \"%s\""
+
 msgid "Notify level for buffer"
 msgstr "Nível de notificação para o buffer"
 
@@ -3455,13 +3535,12 @@ msgid "bar type (root, window, window_active, window_inactive)"
 msgstr "tipo da barra (root, window, window_active, window_inactive)"
 
 msgid ""
-"condition(s) for displaying bar (for bars of type \"window\"): \"active\" = "
-"window must be active, \"inactive\" = window must be inactive, \"nicklist\" "
-"= buffer must have a nicklist"
+"condition(s) for displaying bar (for bars of type \"window\"): a simple "
+"condition: \"active\", \"inactive\", \"nicklist\" (window must be active/"
+"inactive, buffer must have a nicklist), or an expression with condition(s) "
+"(see /help eval), like: \"${nicklist} && ${window.win_width} > 100\" (local "
+"variables for expression are ${active}, ${inactive} and ${nicklist})"
 msgstr ""
-"condição(ões) para exibição da barra (para barras do tipo \"window\"): "
-"\"active\" = janela deve estar ativa, \"inactive\" = janela deve estar "
-"inativa, \"nicklist\" = buffer deve possuir uma lista de apelidos"
 
 msgid "bar position (bottom, top, left, right)"
 msgstr ""
@@ -8760,6 +8839,15 @@ msgstr ""
 msgid "Constants"
 msgstr ""
 
+#~ msgid ""
+#~ "condition(s) for displaying bar (for bars of type \"window\"): \"active\" "
+#~ "= window must be active, \"inactive\" = window must be inactive, "
+#~ "\"nicklist\" = buffer must have a nicklist"
+#~ msgstr ""
+#~ "condição(ões) para exibição da barra (para barras do tipo \"window\"): "
+#~ "\"active\" = janela deve estar ativa, \"inactive\" = janela deve estar "
+#~ "inativa, \"nicklist\" = buffer deve possuir uma lista de apelidos"
+
 #~ msgid "use IPv6 protocol for server communication"
 #~ msgstr "usar protocolo IPv6 para comunicação com o servidor"
 
diff --git a/po/ru.po b/po/ru.po
index 8544373f6..eaa57a380 100644
--- a/po/ru.po
+++ b/po/ru.po
@@ -21,7 +21,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat 0.4.0-dev\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2012-10-20 17:54+0200\n"
+"POT-Creation-Date: 2012-11-02 08:59+0100\n"
 "PO-Revision-Date: 2012-09-29 11:43+0200\n"
 "Last-Translator: Aleksey V Zapparov AKA ixti <ixti@member.fsf.org>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -254,6 +254,13 @@ msgstr "Содержимое буфера записано в файл журн
 msgid "Debug disabled for \"%s\""
 msgstr "Отладка отключена для \"%s\""
 
+msgid "error"
+msgstr ""
+
+#, c-format
+msgid "%sError in expression to evaluate"
+msgstr ""
+
 #, fuzzy, c-format
 msgid "  %s[%s%s%s]%s buffer: %s%s%s / tags: %s / regex: %s %s"
 msgstr "       (нет обработчика сообщений)\n"
@@ -890,10 +897,10 @@ msgid "manage bars"
 msgstr "управление буферами"
 
 msgid ""
-"list|listfull|listitems || add <name> <type>[,<cond1>[,<cond2>...]] "
-"<position> <size> <separator> <item1>[,<item2>...] || default [input|title|"
-"status|nicklist] || del <name>|-all || set <name> <option> <value> || hide|"
-"show|toggle <name> || scroll <name> <window> <scroll_value>"
+"list|listfull|listitems || add <name> <type>[,<condition>] <position> <size> "
+"<separator> <item1>[,<item2>...] || default [input|title|status|nicklist] || "
+"del <name>|-all || set <name> <option> <value> || hide|show|toggle <name> || "
+"scroll <name> <window> <scroll_value>"
 msgstr ""
 
 msgid ""
@@ -904,11 +911,13 @@ msgid ""
 "         name: name of bar (must be unique)\n"
 "         type:   root: outside windows,\n"
 "               window: inside windows, with optional conditions (see below)\n"
-"    cond1,...: condition(s) for displaying bar (only for type \"window\"):\n"
+"    condition: condition(s) for displaying bar (only for type \"window\"):\n"
 "                 active: on active window\n"
 "               inactive: on inactive windows\n"
 "               nicklist: on windows with nicklist\n"
-"               without condition, bar is always displayed\n"
+"               other condition: see /help weechat.bar.xxx.conditions and /"
+"help eval\n"
+"               without condition, the bar is always displayed\n"
 "     position: bottom, top, left or right\n"
 "         size: size of bar (in chars)\n"
 "    separator: 1 for using separator (line), 0 or nothing means no "
@@ -1138,6 +1147,71 @@ msgstr ""
 "файл\n"
 "windows: отобразить дерево окон"
 
+msgid "evaluate expression and send result to buffer"
+msgstr ""
+
+msgid "[-n] <expression> || [-n] <expression1> <operator> <expression2>"
+msgstr ""
+
+msgid ""
+"        -n: display result without sending it to buffer (debug mode)\n"
+"expression: expression to evaluate, variables with format ${variable} are "
+"replaced (see below)\n"
+"  operator: a logical or comparison operator:\n"
+"            - logical operators:\n"
+"                &&  boolean \"and\"\n"
+"                ||  boolean \"or\"\n"
+"            - comparison operators:\n"
+"                ==  equal\n"
+"                !=  not equal\n"
+"                <=  less or equal\n"
+"                <   less\n"
+"                >=  greater or equal\n"
+"                >   greater\n"
+"                =~  is matching regex\n"
+"                !~  is NOT matching regex\n"
+"\n"
+"An expression is considered as \"true\" if it is not NULL, not empty, and "
+"different from \"0\".\n"
+"The comparison is made using integers if the two expressions are valid "
+"integers.\n"
+"To force a string comparison, add double quotes around each expression, for "
+"example:\n"
+"  50 > 100      ==> 0\n"
+"  \"50\" > \"100\"  ==> 1\n"
+"\n"
+"Some variables are replaced in expression, using the format ${variable}, "
+"variable can be, by order of prioity :\n"
+"  1. the name of an option (file.section.option)\n"
+"  2. a hdata name/variable (the value is automatically converted to string), "
+"by default \"window\" and \"buffer\" point to current window/buffer.\n"
+"Format for hdata can be one of following:\n"
+"  hdata.var1.var2...: start with a hdata (pointer must be known), and ask "
+"variables one after one (other hdata can be followed)\n"
+"  hdata(list).var1.var2...: start with a hdata using a list, for example:\n"
+"    ${buffer[gui_buffers].full_name}: full name of first buffer in linked "
+"list of buffers\n"
+"    ${plugin[weechat_plugins].name}: name of first plugin in linked list of "
+"plugins\n"
+"For name of hdata and variables, please look at \"Plugin API reference\", "
+"function \"weechat_hdata_get\".\n"
+"\n"
+"Examples:\n"
+"  /eval -n ${weechat.look.scroll_amount}  ==> 3\n"
+"  /eval -n ${window}                      ==> 0x2549aa0\n"
+"  /eval -n ${window.buffer}               ==> 0x2549320\n"
+"  /eval -n ${window.buffer.full_name}     ==> core.weechat\n"
+"  /eval -n ${window.buffer.number}        ==> 1\n"
+"  /eval -n ${window.buffer.number} > 2    ==> 0\n"
+"  /eval -n ${window.win_width} > 100      ==> 1\n"
+"  /eval -n (8 > 12) || (5 > 2)            ==> 1\n"
+"  /eval -n (8 > 12) && (5 > 2)            ==> 0\n"
+"  /eval -n abcd =~ ^ABC                   ==> 1\n"
+"  /eval -n abcd =~ (?-i)^ABC              ==> 0\n"
+"  /eval -n abcd =~ (?-i)^abc              ==> 1\n"
+"  /eval -n abcd !~ abc                    ==> 0"
+msgstr ""
+
 msgid ""
 "filter messages in buffers, to hide/show them according to tags or regex"
 msgstr ""
@@ -1938,6 +2012,10 @@ msgstr ""
 msgid "%sError: palette option must be numeric"
 msgstr "%s не могу сохранить конфигурационный файл pluginов\n"
 
+#, fuzzy, c-format
+msgid "%sWarning: unknown option for section \"%s\": %s (value: \"%s\")"
+msgstr "%s %s, строка %d: неизвестный идентификатор секции (\"%s\")\n"
+
 #, fuzzy
 msgid "Notify level for buffer"
 msgstr "не найдено имя канала для буфера"
@@ -3055,9 +3133,11 @@ msgid "bar type (root, window, window_active, window_inactive)"
 msgstr ""
 
 msgid ""
-"condition(s) for displaying bar (for bars of type \"window\"): \"active\" = "
-"window must be active, \"inactive\" = window must be inactive, \"nicklist\" "
-"= buffer must have a nicklist"
+"condition(s) for displaying bar (for bars of type \"window\"): a simple "
+"condition: \"active\", \"inactive\", \"nicklist\" (window must be active/"
+"inactive, buffer must have a nicklist), or an expression with condition(s) "
+"(see /help eval), like: \"${nicklist} && ${window.win_width} > 100\" (local "
+"variables for expression are ${active}, ${inactive} and ${nicklist})"
 msgstr ""
 
 #, fuzzy
diff --git a/po/srcfiles.cmake b/po/srcfiles.cmake
index be33e36da..fcbf7c67e 100644
--- a/po/srcfiles.cmake
+++ b/po/srcfiles.cmake
@@ -13,6 +13,8 @@ SET(WEECHAT_SOURCES
 ./src/core/wee-config.h
 ./src/core/wee-debug.c
 ./src/core/wee-debug.h
+./src/core/wee-eval.c
+./src/core/wee-eval.h
 ./src/core/wee-hook.c
 ./src/core/wee-hook.h
 ./src/core/wee-infolist.c
diff --git a/po/weechat.pot b/po/weechat.pot
index bd7bb605e..6e129f57a 100644
--- a/po/weechat.pot
+++ b/po/weechat.pot
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2012-10-20 17:54+0200\n"
+"POT-Creation-Date: 2012-11-02 08:59+0100\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -212,6 +212,13 @@ msgstr ""
 msgid "Debug disabled for \"%s\""
 msgstr ""
 
+msgid "error"
+msgstr ""
+
+#, c-format
+msgid "%sError in expression to evaluate"
+msgstr ""
+
 #, c-format
 msgid "  %s[%s%s%s]%s buffer: %s%s%s / tags: %s / regex: %s %s"
 msgstr ""
@@ -771,10 +778,10 @@ msgid "manage bars"
 msgstr ""
 
 msgid ""
-"list|listfull|listitems || add <name> <type>[,<cond1>[,<cond2>...]] "
-"<position> <size> <separator> <item1>[,<item2>...] || default [input|title|"
-"status|nicklist] || del <name>|-all || set <name> <option> <value> || hide|"
-"show|toggle <name> || scroll <name> <window> <scroll_value>"
+"list|listfull|listitems || add <name> <type>[,<condition>] <position> <size> "
+"<separator> <item1>[,<item2>...] || default [input|title|status|nicklist] || "
+"del <name>|-all || set <name> <option> <value> || hide|show|toggle <name> || "
+"scroll <name> <window> <scroll_value>"
 msgstr ""
 
 msgid ""
@@ -785,11 +792,13 @@ msgid ""
 "         name: name of bar (must be unique)\n"
 "         type:   root: outside windows,\n"
 "               window: inside windows, with optional conditions (see below)\n"
-"    cond1,...: condition(s) for displaying bar (only for type \"window\"):\n"
+"    condition: condition(s) for displaying bar (only for type \"window\"):\n"
 "                 active: on active window\n"
 "               inactive: on inactive windows\n"
 "               nicklist: on windows with nicklist\n"
-"               without condition, bar is always displayed\n"
+"               other condition: see /help weechat.bar.xxx.conditions and /"
+"help eval\n"
+"               without condition, the bar is always displayed\n"
 "     position: bottom, top, left or right\n"
 "         size: size of bar (in chars)\n"
 "    separator: 1 for using separator (line), 0 or nothing means no "
@@ -980,6 +989,71 @@ msgid ""
 "  windows: display windows tree"
 msgstr ""
 
+msgid "evaluate expression and send result to buffer"
+msgstr ""
+
+msgid "[-n] <expression> || [-n] <expression1> <operator> <expression2>"
+msgstr ""
+
+msgid ""
+"        -n: display result without sending it to buffer (debug mode)\n"
+"expression: expression to evaluate, variables with format ${variable} are "
+"replaced (see below)\n"
+"  operator: a logical or comparison operator:\n"
+"            - logical operators:\n"
+"                &&  boolean \"and\"\n"
+"                ||  boolean \"or\"\n"
+"            - comparison operators:\n"
+"                ==  equal\n"
+"                !=  not equal\n"
+"                <=  less or equal\n"
+"                <   less\n"
+"                >=  greater or equal\n"
+"                >   greater\n"
+"                =~  is matching regex\n"
+"                !~  is NOT matching regex\n"
+"\n"
+"An expression is considered as \"true\" if it is not NULL, not empty, and "
+"different from \"0\".\n"
+"The comparison is made using integers if the two expressions are valid "
+"integers.\n"
+"To force a string comparison, add double quotes around each expression, for "
+"example:\n"
+"  50 > 100      ==> 0\n"
+"  \"50\" > \"100\"  ==> 1\n"
+"\n"
+"Some variables are replaced in expression, using the format ${variable}, "
+"variable can be, by order of prioity :\n"
+"  1. the name of an option (file.section.option)\n"
+"  2. a hdata name/variable (the value is automatically converted to string), "
+"by default \"window\" and \"buffer\" point to current window/buffer.\n"
+"Format for hdata can be one of following:\n"
+"  hdata.var1.var2...: start with a hdata (pointer must be known), and ask "
+"variables one after one (other hdata can be followed)\n"
+"  hdata(list).var1.var2...: start with a hdata using a list, for example:\n"
+"    ${buffer[gui_buffers].full_name}: full name of first buffer in linked "
+"list of buffers\n"
+"    ${plugin[weechat_plugins].name}: name of first plugin in linked list of "
+"plugins\n"
+"For name of hdata and variables, please look at \"Plugin API reference\", "
+"function \"weechat_hdata_get\".\n"
+"\n"
+"Examples:\n"
+"  /eval -n ${weechat.look.scroll_amount}  ==> 3\n"
+"  /eval -n ${window}                      ==> 0x2549aa0\n"
+"  /eval -n ${window.buffer}               ==> 0x2549320\n"
+"  /eval -n ${window.buffer.full_name}     ==> core.weechat\n"
+"  /eval -n ${window.buffer.number}        ==> 1\n"
+"  /eval -n ${window.buffer.number} > 2    ==> 0\n"
+"  /eval -n ${window.win_width} > 100      ==> 1\n"
+"  /eval -n (8 > 12) || (5 > 2)            ==> 1\n"
+"  /eval -n (8 > 12) && (5 > 2)            ==> 0\n"
+"  /eval -n abcd =~ ^ABC                   ==> 1\n"
+"  /eval -n abcd =~ (?-i)^ABC              ==> 0\n"
+"  /eval -n abcd =~ (?-i)^abc              ==> 1\n"
+"  /eval -n abcd !~ abc                    ==> 0"
+msgstr ""
+
 msgid ""
 "filter messages in buffers, to hide/show them according to tags or regex"
 msgstr ""
@@ -1683,6 +1757,10 @@ msgstr ""
 msgid "%sError: palette option must be numeric"
 msgstr ""
 
+#, c-format
+msgid "%sWarning: unknown option for section \"%s\": %s (value: \"%s\")"
+msgstr ""
+
 msgid "Notify level for buffer"
 msgstr ""
 
@@ -2664,9 +2742,11 @@ msgid "bar type (root, window, window_active, window_inactive)"
 msgstr ""
 
 msgid ""
-"condition(s) for displaying bar (for bars of type \"window\"): \"active\" = "
-"window must be active, \"inactive\" = window must be inactive, \"nicklist\" "
-"= buffer must have a nicklist"
+"condition(s) for displaying bar (for bars of type \"window\"): a simple "
+"condition: \"active\", \"inactive\", \"nicklist\" (window must be active/"
+"inactive, buffer must have a nicklist), or an expression with condition(s) "
+"(see /help eval), like: \"${nicklist} && ${window.win_width} > 100\" (local "
+"variables for expression are ${active}, ${inactive} and ${nicklist})"
 msgstr ""
 
 msgid "bar position (bottom, top, left, right)"
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index f5afb1803..984c5be15 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -27,6 +27,7 @@ wee-completion.c wee-completion.h
 wee-config.c wee-config.h
 wee-config-file.c wee-config-file.h
 wee-debug.c wee-debug.h
+wee-eval.c wee-eval.h
 wee-hashtable.c wee-hashtable.h
 wee-hdata.c wee-hdata.h
 wee-hook.c wee-hook.h
diff --git a/src/core/Makefile.am b/src/core/Makefile.am
index ae69f3ec0..6abf84b99 100644
--- a/src/core/Makefile.am
+++ b/src/core/Makefile.am
@@ -35,6 +35,8 @@ lib_weechat_core_a_SOURCES = weechat.c \
                              wee-config-file.h \
                              wee-debug.c \
                              wee-debug.h \
+                             wee-eval.c \
+                             wee-eval.h \
                              wee-hashtable.c \
                              wee-hashtable.h \
                              wee-hdata.c \
diff --git a/src/core/wee-command.c b/src/core/wee-command.c
index 99e26d7a4..c0fce2c86 100644
--- a/src/core/wee-command.c
+++ b/src/core/wee-command.c
@@ -39,6 +39,7 @@
 #include "wee-config.h"
 #include "wee-config-file.h"
 #include "wee-debug.h"
+#include "wee-eval.h"
 #include "wee-hashtable.h"
 #include "wee-hdata.h"
 #include "wee-hook.h"
@@ -1443,6 +1444,73 @@ COMMAND_CALLBACK(debug)
     return WEECHAT_RC_OK;
 }
 
+/*
+ * command_eval: evaluate expression and send result to buffer
+ */
+
+COMMAND_CALLBACK(eval)
+{
+    int print_only;
+    char *result, *ptr_args;
+
+    /* make C compiler happy */
+    (void) buffer;
+    (void) data;
+    (void) argv;
+
+    print_only = 0;
+
+    if (argc < 2)
+        return WEECHAT_RC_OK;
+
+    ptr_args = argv_eol[1];
+    if (string_strcasecmp (argv[1], "-n") == 0)
+    {
+        print_only = 1;
+        ptr_args = argv_eol[2];
+    }
+
+    if (ptr_args)
+    {
+        result = eval_expression (ptr_args, NULL, NULL);
+        if (print_only)
+        {
+            gui_chat_printf_date_tags (NULL, 0, "no_log", ">> %s", ptr_args);
+            if (result)
+            {
+                gui_chat_printf_date_tags (NULL, 0, "no_log", "== %s[%s%s%s]",
+                                           GUI_COLOR(GUI_COLOR_CHAT_DELIMITERS),
+                                           GUI_COLOR(GUI_COLOR_CHAT),
+                                           result,
+                                           GUI_COLOR(GUI_COLOR_CHAT_DELIMITERS));
+            }
+            else
+            {
+                gui_chat_printf_date_tags (NULL, 0, "no_log", "== %s<%s%s%s>",
+                                           GUI_COLOR(GUI_COLOR_CHAT_DELIMITERS),
+                                           GUI_COLOR(GUI_COLOR_CHAT),
+                                           _("error"),
+                                           GUI_COLOR(GUI_COLOR_CHAT_DELIMITERS));
+            }
+        }
+        else
+        {
+            if (result)
+                input_data (buffer, result);
+            else
+            {
+                gui_chat_printf (NULL,
+                                 _("%sError in expression to evaluate"),
+                                 gui_chat_prefix[GUI_CHAT_PREFIX_ERROR]);
+            }
+        }
+        if (result)
+            free (result);
+    }
+
+    return WEECHAT_RC_OK;
+}
+
 /*
  * command_filter_display: display one filter
  */
@@ -5438,8 +5506,8 @@ command_init ()
     hook_command (NULL, "bar",
                   N_("manage bars"),
                   N_("list|listfull|listitems"
-                     " || add <name> <type>[,<cond1>[,<cond2>...]] <position> "
-                     "<size> <separator> <item1>[,<item2>...]"
+                     " || add <name> <type>[,<condition>] <position> <size> "
+                     "<separator> <item1>[,<item2>...]"
                      " || default [input|title|status|nicklist]"
                      " || del <name>|-all"
                      " || set <name> <option> <value>"
@@ -5453,12 +5521,15 @@ command_init ()
                      "         type:   root: outside windows,\n"
                      "               window: inside windows, with optional "
                      "conditions (see below)\n"
-                     "    cond1,...: condition(s) for displaying bar (only for "
+                     "    condition: condition(s) for displaying bar (only for "
                      "type \"window\"):\n"
                      "                 active: on active window\n"
                      "               inactive: on inactive windows\n"
                      "               nicklist: on windows with nicklist\n"
-                     "               without condition, bar is always displayed\n"
+                     "               other condition: see /help "
+                     "weechat.bar.xxx.conditions and /help eval\n"
+                     "               without condition, the bar is always "
+                     "displayed\n"
                      "     position: bottom, top, left or right\n"
                      "         size: size of bar (in chars)\n"
                      "    separator: 1 for using separator (line), 0 or nothing "
@@ -5683,6 +5754,69 @@ command_init ()
                   " || term"
                   " || windows",
                   &command_debug, NULL);
+    hook_command (NULL, "eval",
+                  N_("evaluate expression and send result to buffer"),
+                  N_("[-n] <expression>"
+                     " || [-n] <expression1> <operator> <expression2>"),
+                  N_("        -n: display result without sending it to buffer "
+                     "(debug mode)\n"
+                     "expression: expression to evaluate, variables with format "
+                     "${variable} are replaced (see below)\n"
+                     "  operator: a logical or comparison operator:\n"
+                     "            - logical operators:\n"
+                     "                &&  boolean \"and\"\n"
+                     "                ||  boolean \"or\"\n"
+                     "            - comparison operators:\n"
+                     "                ==  equal\n"
+                     "                !=  not equal\n"
+                     "                <=  less or equal\n"
+                     "                <   less\n"
+                     "                >=  greater or equal\n"
+                     "                >   greater\n"
+                     "                =~  is matching regex\n"
+                     "                !~  is NOT matching regex\n\n"
+                     "An expression is considered as \"true\" if it is not NULL, "
+                     "not empty, and different from \"0\".\n"
+                     "The comparison is made using integers if the two "
+                     "expressions are valid integers.\n"
+                     "To force a string comparison, add double quotes around "
+                     "each expression, for example:\n"
+                     "  50 > 100      ==> 0\n"
+                     "  \"50\" > \"100\"  ==> 1\n\n"
+                     "Some variables are replaced in expression, using the "
+                     "format ${variable}, variable can be, by order of prioity :\n"
+                     "  1. the name of an option (file.section.option)\n"
+                     "  2. a hdata name/variable (the value is automatically "
+                     "converted to string), by default \"window\" and \"buffer\" "
+                     "point to current window/buffer.\n"
+                     "Format for hdata can be one of following:\n"
+                     "  hdata.var1.var2...: start with a hdata (pointer must be "
+                     "known), and ask variables one after one (other hdata can "
+                     "be followed)\n"
+                     "  hdata(list).var1.var2...: start with a hdata using a "
+                     "list, for example:\n"
+                     "    ${buffer[gui_buffers].full_name}: full name of first "
+                     "buffer in linked list of buffers\n"
+                     "    ${plugin[weechat_plugins].name}: name of first plugin "
+                     "in linked list of plugins\n"
+                     "For name of hdata and variables, please look at \"Plugin "
+                     "API reference\", function \"weechat_hdata_get\".\n\n"
+                     "Examples:\n"
+                     "  /eval -n ${weechat.look.scroll_amount}  ==> 3\n"
+                     "  /eval -n ${window}                      ==> 0x2549aa0\n"
+                     "  /eval -n ${window.buffer}               ==> 0x2549320\n"
+                     "  /eval -n ${window.buffer.full_name}     ==> core.weechat\n"
+                     "  /eval -n ${window.buffer.number}        ==> 1\n"
+                     "  /eval -n ${window.buffer.number} > 2    ==> 0\n"
+                     "  /eval -n ${window.win_width} > 100      ==> 1\n"
+                     "  /eval -n (8 > 12) || (5 > 2)            ==> 1\n"
+                     "  /eval -n (8 > 12) && (5 > 2)            ==> 0\n"
+                     "  /eval -n abcd =~ ^ABC                   ==> 1\n"
+                     "  /eval -n abcd =~ (?-i)^ABC              ==> 0\n"
+                     "  /eval -n abcd =~ (?-i)^abc              ==> 1\n"
+                     "  /eval -n abcd !~ abc                    ==> 0"),
+                  "-n",
+                  &command_eval, NULL);
     hook_command (NULL, "filter",
                   N_("filter messages in buffers, to hide/show them according "
                      "to tags or regex"),
diff --git a/src/core/wee-config.c b/src/core/wee-config.c
index 7070fe75f..390a75ba6 100644
--- a/src/core/wee-config.c
+++ b/src/core/wee-config.c
@@ -1163,6 +1163,16 @@ config_weechat_proxy_read_cb (void *data, struct t_config_file *config_file,
                         proxy_create_option_temp (ptr_temp_proxy, index_option,
                                                   value);
                     }
+                    else
+                    {
+                        gui_chat_printf (NULL,
+                                         _("%sWarning: unknown option for "
+                                           "section \"%s\": %s (value: \"%s\")"),
+                                         gui_chat_prefix[GUI_CHAT_PREFIX_ERROR],
+                                         section->name,
+                                         option_name,
+                                         value);
+                    }
                 }
 
                 free (proxy_name);
@@ -1232,6 +1242,16 @@ config_weechat_bar_read_cb (void *data, struct t_config_file *config_file,
                         gui_bar_create_option_temp (ptr_temp_bar, index_option,
                                                     value);
                     }
+                    else
+                    {
+                        gui_chat_printf (NULL,
+                                         _("%sWarning: unknown option for "
+                                           "section \"%s\": %s (value: \"%s\")"),
+                                         gui_chat_prefix[GUI_CHAT_PREFIX_ERROR],
+                                         section->name,
+                                         option_name,
+                                         value);
+                    }
                 }
 
                 free (bar_name);
diff --git a/src/core/wee-eval.c b/src/core/wee-eval.c
new file mode 100644
index 000000000..45b2e1f01
--- /dev/null
+++ b/src/core/wee-eval.c
@@ -0,0 +1,717 @@
+/*
+ * Copyright (C) 2012 Sebastien Helleu <flashcode@flashtux.org>
+ *
+ * This file is part of WeeChat, the extensible chat client.
+ *
+ * WeeChat is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * WeeChat is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with WeeChat.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * wee-eval.c: evaluate expressions with references to internal vars
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+#include <regex.h>
+
+#include "weechat.h"
+#include "wee-eval.h"
+#include "wee-config-file.h"
+#include "wee-hashtable.h"
+#include "wee-hdata.h"
+#include "wee-hook.h"
+#include "wee-string.h"
+#include "../gui/gui-color.h"
+#include "../gui/gui-window.h"
+#include "../plugins/plugin.h"
+
+
+char *logical_ops[EVAL_NUM_LOGICAL_OPS] = { "&&", "||" };
+char *comparisons[EVAL_NUM_COMPARISONS] = { "==", "!=", "<=", "<", ">=", ">",
+                                            "=~", "!~" };
+
+
+/*
+ * eval_is_true: return 1 if value is true, 0 otherwise
+ *               A value is true if string is non-NULL, non-empty and different
+ *               from "0".
+ */
+
+int
+eval_is_true (const char *value)
+{
+    return (value && value[0] && (strcmp (value, "0") != 0)) ? 1 : 0;
+}
+
+/*
+ * eval_hdata_get_value: get value of hdata using "path" to a variable
+ *                       Note: result must be freed after use
+ */
+
+char *
+eval_hdata_get_value (struct t_hdata *hdata, void *pointer, const char *path)
+{
+    char *value, *old_value, *var_name, str_value[128], *pos;
+    const char *ptr_value, *hdata_name;
+    int type;
+    struct t_hashtable *hashtable;
+
+    value = NULL;
+    var_name = NULL;
+
+    /* NULL pointer? return empty string */
+    if (!pointer)
+        return strdup ("");
+
+    /* no path? just return current pointer as string */
+    if (!path || !path[0])
+    {
+        snprintf (str_value, sizeof (str_value),
+                  "0x%lx", (long unsigned int)pointer);
+        return strdup (str_value);
+    }
+
+    /*
+     * look for name of hdata, for example in "window.buffer.full_name", the
+     * hdata name is "window"
+     */
+    pos = strchr (path, '.');
+    if (pos > path)
+        var_name = string_strndup (path, pos - path);
+    else
+        var_name = strdup (path);
+
+    if (!var_name)
+        goto end;
+
+    /* search type of variable in hdata */
+    type = hdata_get_var_type (hdata, var_name);
+    if (type < 0)
+        goto end;
+
+    /* build a string with the value or variable */
+    switch (type)
+    {
+        case WEECHAT_HDATA_CHAR:
+            snprintf (str_value, sizeof (str_value),
+                      "%c", hdata_char (hdata, pointer, var_name));
+            value = strdup (str_value);
+            break;
+        case WEECHAT_HDATA_INTEGER:
+            snprintf (str_value, sizeof (str_value),
+                      "%d", hdata_integer (hdata, pointer, var_name));
+            value = strdup (str_value);
+            break;
+        case WEECHAT_HDATA_LONG:
+            snprintf (str_value, sizeof (str_value),
+                      "%ld", hdata_long (hdata, pointer, var_name));
+            value = strdup (str_value);
+            break;
+        case WEECHAT_HDATA_STRING:
+            value = strdup (hdata_string (hdata, pointer, var_name));
+            break;
+        case WEECHAT_HDATA_POINTER:
+            pointer = hdata_pointer (hdata, pointer, var_name);
+            snprintf (str_value, sizeof (str_value),
+                      "0x%lx", (long unsigned int)pointer);
+            value = strdup (str_value);
+            break;
+        case WEECHAT_HDATA_TIME:
+            snprintf (str_value, sizeof (str_value),
+                      "%ld", hdata_time (hdata, pointer, var_name));
+            value = strdup (str_value);
+            break;
+        case WEECHAT_HDATA_HASHTABLE:
+            pointer = hdata_hashtable (hdata, pointer, var_name);
+            if (pos)
+            {
+                /*
+                 * for a hashtable, if there is a "." after name of hdata,
+                 * get the value for this key in hashtable
+                 */
+                hashtable = pointer;
+                ptr_value = hashtable_get (hashtable, pos + 1);
+                if (ptr_value)
+                {
+                    switch (hashtable->type_values)
+                    {
+                        case HASHTABLE_INTEGER:
+                            snprintf (str_value, sizeof (str_value),
+                                      "%d", *((int *)ptr_value));
+                            value = strdup (str_value);
+                            break;
+                        case HASHTABLE_STRING:
+                            value = strdup (ptr_value);
+                            break;
+                        case HASHTABLE_POINTER:
+                        case HASHTABLE_BUFFER:
+                            snprintf (str_value, sizeof (str_value),
+                                      "0x%lx", (long unsigned int)ptr_value);
+                            value = strdup (str_value);
+                            break;
+                        case HASHTABLE_TIME:
+                            snprintf (str_value, sizeof (str_value),
+                                      "%ld", *((time_t *)ptr_value));
+                            value = strdup (str_value);
+                            break;
+                        case HASHTABLE_NUM_TYPES:
+                            break;
+                    }
+                }
+            }
+            else
+            {
+                snprintf (str_value, sizeof (str_value),
+                          "0x%lx", (long unsigned int)pointer);
+                value = strdup (str_value);
+            }
+            break;
+    }
+
+    /*
+     * if we are on a pointer and that something else is in path (after "."),
+     * go on with this pointer and remaining path
+     */
+    if ((type == WEECHAT_HDATA_POINTER) && pos)
+    {
+        hdata_name = hdata_get_var_hdata (hdata, var_name);
+        if (!hdata_name)
+            goto end;
+
+        hdata = hook_hdata_get (NULL, hdata_name);
+        old_value = value;
+        value = eval_hdata_get_value (hdata, pointer, (pos) ? pos + 1 : NULL);
+        if (old_value)
+            free (old_value);
+    }
+
+end:
+    if (var_name)
+        free (var_name);
+
+    return value;
+}
+
+/*
+ * eval_replace_vars_cb: callback to replace variables, which can be,
+ *                       by order of priority:
+ *                         1. an extra variable (from hashtable "extra_vars")
+ *                         2. an name of option (file.section.option)
+ *                         3. a hdata name/variable
+ *                       Examples:
+ *                         option: ${weechat.look.scroll_amount}
+ *                         hdata : ${window.buffer.full_name}
+ *                                 ${window.buffer.local_variables.type}
+ */
+
+char *
+eval_replace_vars_cb (void *data, const char *text)
+{
+    struct t_hashtable *pointers, *extra_vars;
+    struct t_config_option *ptr_option;
+    char str_value[64], *value, *pos, *pos1, *pos2, *hdata_name, *list_name;
+    char *tmp;
+    const char *ptr_value;
+    struct t_hdata *hdata;
+    void *pointer;
+
+    pointers = (struct t_hashtable *)(((void **)data)[0]);
+    extra_vars = (struct t_hashtable *)(((void **)data)[1]);
+
+    /* first look for var in hashtable "extra_vars" */
+    ptr_value = hashtable_get (extra_vars, text);
+    if (ptr_value)
+        return strdup (ptr_value);
+
+    /* look for name of option: if found, return this value */
+    config_file_search_with_string (text, NULL, NULL, &ptr_option, NULL);
+    if (ptr_option)
+    {
+        switch (ptr_option->type)
+        {
+            case CONFIG_OPTION_TYPE_BOOLEAN:
+                return strdup (CONFIG_BOOLEAN(ptr_option) ? EVAL_STR_TRUE : EVAL_STR_FALSE);
+            case CONFIG_OPTION_TYPE_INTEGER:
+                if (ptr_option->string_values)
+                    return strdup (ptr_option->string_values[CONFIG_INTEGER(ptr_option)]);
+                snprintf (str_value, sizeof (str_value),
+                          "%d", CONFIG_INTEGER(ptr_option));
+                return strdup (str_value);
+            case CONFIG_OPTION_TYPE_STRING:
+                return strdup (CONFIG_STRING(ptr_option));
+            case CONFIG_OPTION_TYPE_COLOR:
+                return strdup (gui_color_get_name (CONFIG_COLOR(ptr_option)));
+            case CONFIG_NUM_OPTION_TYPES:
+                return NULL;
+        }
+    }
+
+    /* look for hdata */
+    value = NULL;
+    hdata_name = NULL;
+    list_name = NULL;
+    pointer = NULL;
+
+    pos = strchr (text, '.');
+    if (pos > text)
+        hdata_name = string_strndup (text, pos - text);
+    else
+        hdata_name = strdup (text);
+
+    if (!hdata_name)
+        goto end;
+
+    pos1 = strchr (hdata_name, '[');
+    if (pos1 > hdata_name)
+    {
+        pos2 = strchr (pos1 + 1, ']');
+        if (pos2 > pos1 + 1)
+        {
+            list_name = string_strndup (pos1 + 1, pos2 - pos1 - 1);
+        }
+        tmp = string_strndup (hdata_name, pos1 - hdata_name);
+        if (tmp)
+        {
+            free (hdata_name);
+            hdata_name = tmp;
+        }
+    }
+
+    hdata = hook_hdata_get (NULL, hdata_name);
+    if (!hdata)
+        goto end;
+
+    if (list_name)
+        pointer = hdata_get_list (hdata, list_name);
+    if (!pointer)
+    {
+        pointer = hashtable_get (pointers, hdata_name);
+        if (!pointer)
+            goto end;
+    }
+
+    value = eval_hdata_get_value (hdata, pointer, (pos) ? pos + 1 : NULL);
+
+end:
+    if (hdata_name)
+        free (hdata_name);
+    if (list_name)
+        free (list_name);
+
+    return (value) ? value : strdup ("");
+}
+
+/*
+ * eval_replace_vars: replace variables in a string
+ */
+
+char *
+eval_replace_vars (const char *expr, struct t_hashtable *pointers,
+                   struct t_hashtable *extra_vars)
+{
+    int errors;
+    void *ptr[2];
+
+    ptr[0] = pointers;
+    ptr[1] = extra_vars;
+
+    return string_replace_with_callback (expr,
+                                         &eval_replace_vars_cb,
+                                         ptr,
+                                         &errors);
+}
+
+/*
+ * eval_compare: compate two expressions
+ */
+
+char *
+eval_compare (const char *expr1, int comparison, const char *expr2)
+{
+    int rc, string_compare, length1, length2;
+    regex_t regex;
+    long value1, value2;
+    char *error;
+
+    rc = 0;
+    string_compare = 0;
+
+    if (!expr1 || !expr2)
+        goto end;
+
+    if ((comparison == EVAL_COMPARE_REGEX_MATCHING)
+        || (comparison == EVAL_COMPARE_REGEX_NOT_MATCHING))
+    {
+        if (string_regcomp (&regex, expr2,
+                            REG_EXTENDED | REG_ICASE | REG_NOSUB) != 0)
+        {
+            goto end;
+        }
+        rc = (regexec (&regex, expr1, 0, NULL, 0) == 0) ? 1 : 0;
+        if (comparison == EVAL_COMPARE_REGEX_NOT_MATCHING)
+            rc ^= 1;
+        goto end;
+    }
+
+    length1 = strlen (expr1);
+    length2 = strlen (expr2);
+
+    /*
+     * string comparison is forced if expr1 and expr2 have double quotes at
+     * beginning/end
+     */
+    if (((length1 == 0) || ((expr1[0] == '"') && expr1[length1 - 1] == '"'))
+        && ((length2 == 0) || ((expr2[0] == '"') && expr2[length2 - 1] == '"')))
+    {
+        string_compare = 1;
+    }
+
+    if (!string_compare)
+    {
+        value1 = strtol (expr1, &error, 10);
+        if (!error || error[0])
+            string_compare = 1;
+        else
+        {
+            value2 = strtol (expr2, &error, 10);
+            if (!error || error[0])
+                string_compare = 1;
+        }
+    }
+
+    if (string_compare)
+        rc = strcmp (expr1, expr2);
+    else
+        rc = (value1 < value2) ? -1 : ((value1 > value2) ? 1 : 0);
+
+    switch (comparison)
+    {
+        case EVAL_COMPARE_EQUAL:
+            rc = (rc == 0);
+            break;
+        case EVAL_COMPARE_NOT_EQUAL:
+            rc = (rc != 0);
+            break;
+        case EVAL_COMPARE_LESS_EQUAL:
+            rc = (rc <= 0);
+            break;
+        case EVAL_COMPARE_LESS:
+            rc = (rc < 0);
+            break;
+        case EVAL_COMPARE_GREATER_EQUAL:
+            rc = (rc >= 0);
+            break;
+        case EVAL_COMPARE_GREATER:
+            rc = (rc > 0);
+            break;
+        case EVAL_NUM_COMPARISONS:
+            break;
+    }
+
+end:
+    return strdup ((rc) ? EVAL_STR_TRUE : EVAL_STR_FALSE);
+}
+
+/*
+ * eval_expression_internal: evaluate an expression and return a string with
+ *                           the result (see function eval_expression())
+ *                           (should not be called directly)
+ *                           Argument keep_parentheses is almost always 0,
+ *                           it is 1 only if the expression is a regex (to keep
+ *                           flags inside the parentheses)
+ */
+
+char *
+eval_expression_internal (const char *expr, struct t_hashtable *pointers,
+                          struct t_hashtable *extra_vars,
+                          int keep_parentheses)
+{
+    int logic, comp, length, level, rc;
+    const char *pos_end;
+    char *expr2, *sub_expr, *pos, *value, *tmp_value, *tmp_value2;
+
+    value = NULL;
+
+    if (!expr)
+        return NULL;
+
+    if (!expr[0])
+        return strdup (expr);
+
+    /*
+     * skip spaces at beginning of string
+     */
+    while (expr[0] == ' ')
+    {
+        expr++;
+    }
+    if (!expr[0])
+        return strdup (expr);
+
+    /* skip spaces at end of string */
+    pos_end = expr + strlen (expr) - 1;
+    while ((pos_end > expr) && (pos_end[0] == ' '))
+    {
+        pos_end--;
+    }
+
+    expr2 = string_strndup (expr, pos_end + 1 - expr);
+    if (!expr2)
+        return NULL;
+
+    /* evaluate sub-expression in parentheses and replace it with value */
+    if (!keep_parentheses)
+    {
+        while (expr2[0] == '(')
+        {
+            level = 0;
+            pos = expr2 + 1;
+            while (pos[0])
+            {
+                if (pos[0] == '(')
+                    level++;
+                else if (pos[0] == ')')
+                {
+                    if (level == 0)
+                        break;
+                    level--;
+                }
+                pos++;
+            }
+            /* closing parenthese not found */
+            if (pos[0] != ')')
+                goto end;
+            sub_expr = string_strndup (expr2 + 1, pos - expr2 - 1);
+            if (!sub_expr)
+                goto end;
+            tmp_value = eval_expression_internal (sub_expr, pointers, extra_vars, 0);
+            free (sub_expr);
+            if (!pos[1])
+            {
+                /* nothing after ')', then return value of sub-expression as-is */
+                value = tmp_value;
+                goto end;
+            }
+            length = ((tmp_value) ? strlen (tmp_value) : 0) + 1 + strlen (pos + 1) + 1;
+            tmp_value2 = malloc (length);
+            if (!tmp_value2)
+                goto end;
+            tmp_value2[0] = '\0';
+            if (tmp_value)
+                strcat (tmp_value2, tmp_value);
+            strcat (tmp_value2, " ");
+            strcat (tmp_value2, pos + 1);
+            free (expr2);
+            expr2 = tmp_value2;
+        }
+    }
+
+    /*
+     * search for a logical operator, and if one is found:
+     * - split expression into two sub-expressions
+     * - evaluate first sub-expression
+     * - if needed, evaluate second sub-expression
+     * - return result
+     */
+    for (logic = 0; logic < EVAL_NUM_LOGICAL_OPS; logic++)
+    {
+        pos = strstr (expr2, logical_ops[logic]);
+        if (pos > expr2)
+        {
+            pos_end = pos - 1;
+            while ((pos_end > expr2) && (pos_end[0] == ' '))
+            {
+                pos_end--;
+            }
+            sub_expr = string_strndup (expr2, pos_end + 1 - expr2);
+            if (!sub_expr)
+                goto end;
+            tmp_value = eval_expression_internal (sub_expr, pointers, extra_vars, 0);
+            free (sub_expr);
+            rc = eval_is_true (tmp_value);
+            /*
+             * if rc == 0 with "&&" or rc == 1 with "||", no need to evaluate
+             * second sub-expression, just return the rc
+             */
+            if ((!rc && (logic == EVAL_LOGICAL_OP_AND))
+                || (rc && (logic == EVAL_LOGICAL_OP_OR)))
+            {
+                if (tmp_value)
+                    free (tmp_value);
+                value = strdup ((rc) ? EVAL_STR_TRUE : EVAL_STR_FALSE);
+                goto end;
+            }
+            pos += strlen (logical_ops[logic]);
+            while (pos[0] == ' ')
+            {
+                pos++;
+            }
+            tmp_value = eval_expression_internal (pos, pointers, extra_vars, 0);
+            rc = eval_is_true (tmp_value);
+            if (tmp_value)
+                free (tmp_value);
+            value = strdup ((rc) ? EVAL_STR_TRUE : EVAL_STR_FALSE);
+            goto end;
+        }
+    }
+
+    /*
+     * search for a comparison, and if one is found:
+     * - split expression into two sub-expressions
+     * - evaluate the two sub-expressions
+     * - compare sub-expressions
+     * - return result
+     */
+    for (comp = 0; comp < EVAL_NUM_COMPARISONS; comp++)
+    {
+        pos = strstr (expr2, comparisons[comp]);
+        if (pos > expr2)
+        {
+            pos_end = pos - 1;
+            while ((pos_end > expr2) && (pos_end[0] == ' '))
+            {
+                pos_end--;
+            }
+            sub_expr = string_strndup (expr2, pos_end + 1 - expr2);
+            if (!sub_expr)
+                goto end;
+            tmp_value = eval_expression_internal (sub_expr, pointers, extra_vars, 0);
+            free (sub_expr);
+            pos += strlen (comparisons[comp]);
+            while (pos[0] == ' ')
+            {
+                pos++;
+            }
+            tmp_value2 = eval_expression_internal (pos, pointers, extra_vars,
+                                                   ((comp == EVAL_COMPARE_REGEX_MATCHING)
+                                                    || (comp == EVAL_COMPARE_REGEX_NOT_MATCHING)) ? 1 : 0);
+            value = eval_compare (tmp_value, comp, tmp_value2);
+            if (tmp_value)
+                free (tmp_value);
+            if (tmp_value2)
+                free (tmp_value2);
+            goto end;
+        }
+    }
+
+    /*
+     * at this point, there is no more logical operator neither comparison,
+     * so we just replace variables in string and return the result
+     */
+    value = eval_replace_vars (expr2, pointers, extra_vars);
+
+end:
+    if (expr2)
+        free (expr2);
+
+    return value;
+}
+
+/*
+ * eval_expression: evaluate an expression and return a string with the result
+ *                  The hashtable "pointers" must have string for keys, pointer
+ *                  for values.
+ *                  The hashtable "extra_vars" must have string for keys and
+ *                  values.
+ *                  The expression can contain:
+ *                  - conditions:  ==  != <  <=  >  >=
+ *                  - logical operators:  &&  ||
+ *                  - parentheses for priority
+ *                  Examples (the [ ] are NOT part of result):
+ *                    >> ${window.buffer.number}
+ *                    == [2]
+ *                    >> buffer:${window.buffer.full_name}
+ *                    == [buffer:irc.freenode.#weechat]
+ *                    >> ${window.buffer.full_name} == irc.freenode.#weechat
+ *                    == [1]
+ *                    >> ${window.buffer.full_name} == irc.freenode.#test
+ *                    == [0]
+ *                    >> ${window.win_width}
+ *                    == [112]
+ *                    >> ${window.win_height}
+ *                    == [40]
+ *                    >> ${window.win_width} >= 30 && ${window.win_height} >= 20
+ *                    == [1]
+ *                  Note: result must be freed after use
+ */
+
+char *
+eval_expression (const char *expr, struct t_hashtable *pointers,
+                 struct t_hashtable *extra_vars)
+{
+    int pointers_created, extra_vars_created;
+    char *value;
+    struct t_gui_window *window;
+
+    if (!expr)
+        return NULL;
+
+    pointers_created = 0;
+    extra_vars_created = 0;
+
+    /* create hashtable pointers if it's NULL */
+    if (!pointers)
+    {
+        pointers = hashtable_new (16,
+                                  WEECHAT_HASHTABLE_STRING,
+                                  WEECHAT_HASHTABLE_POINTER,
+                                  NULL,
+                                  NULL);
+        if (!pointers)
+            return NULL;
+        pointers_created = 1;
+    }
+
+    /*
+     * set window/buffer with pointer to current window/buffer
+     * (if not already defined in the hashtable)
+     */
+    if (gui_current_window)
+    {
+        if (!hashtable_has_key (pointers, "window"))
+            hashtable_set (pointers, "window", gui_current_window);
+        if (!hashtable_has_key (pointers, "buffer"))
+        {
+            window = (struct t_gui_window *)hashtable_get (pointers, "window");
+            if (window)
+                hashtable_set (pointers, "buffer", window->buffer);
+        }
+    }
+
+    /* create hashtable extra_vars if it's NULL */
+    if (!extra_vars)
+    {
+        extra_vars = hashtable_new (16,
+                                    WEECHAT_HASHTABLE_STRING,
+                                    WEECHAT_HASHTABLE_STRING,
+                                    NULL,
+                                    NULL);
+        if (!extra_vars)
+            return NULL;
+        extra_vars_created = 1;
+    }
+
+    value = eval_expression_internal (expr, pointers, extra_vars, 0);
+
+    if (pointers_created)
+        hashtable_free (pointers);
+    if (extra_vars_created)
+        hashtable_free (extra_vars);
+
+    return value;
+}
diff --git a/src/core/wee-eval.h b/src/core/wee-eval.h
new file mode 100644
index 000000000..482de2e2e
--- /dev/null
+++ b/src/core/wee-eval.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2012 Sebastien Helleu <flashcode@flashtux.org>
+ *
+ * This file is part of WeeChat, the extensible chat client.
+ *
+ * WeeChat is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * WeeChat is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with WeeChat.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __WEECHAT_EVAL_H
+#define __WEECHAT_EVAL_H 1
+
+#define EVAL_STR_FALSE "0"
+#define EVAL_STR_TRUE  "1"
+
+struct t_hashtable;
+
+enum t_eval_logical_op
+{
+    EVAL_LOGICAL_OP_AND = 0,
+    EVAL_LOGICAL_OP_OR,
+    /* number of comparison strings */
+    EVAL_NUM_LOGICAL_OPS,
+};
+
+enum t_eval_comparison
+{
+    EVAL_COMPARE_EQUAL = 0,
+    EVAL_COMPARE_NOT_EQUAL,
+    EVAL_COMPARE_LESS_EQUAL,
+    EVAL_COMPARE_LESS,
+    EVAL_COMPARE_GREATER_EQUAL,
+    EVAL_COMPARE_GREATER,
+    EVAL_COMPARE_REGEX_MATCHING,
+    EVAL_COMPARE_REGEX_NOT_MATCHING,
+    /* number of comparison strings */
+    EVAL_NUM_COMPARISONS,
+};
+
+extern int eval_is_true (const char *value);
+extern char *eval_expression (const char *expr,
+                              struct t_hashtable *pointers,
+                              struct t_hashtable *extra_vars);
+
+#endif /* __WEECHAT_EVAL_H */
diff --git a/src/core/wee-string.c b/src/core/wee-string.c
index 1d16d6d0f..269663cb8 100644
--- a/src/core/wee-string.c
+++ b/src/core/wee-string.c
@@ -49,7 +49,6 @@
 #include "weechat.h"
 #include "wee-string.h"
 #include "wee-config.h"
-#include "wee-hashtable.h"
 #include "wee-utf8.h"
 #include "../gui/gui-color.h"
 #include "../plugins/plugin.h"
@@ -1774,28 +1773,29 @@ string_input_for_buffer (const char *string)
 }
 
 /*
- * string_replace_with_hashtable: replace ${codes} with value from hashtable
- *                                "errors" is set with number of keys not found
- *                                in hashtable
+ * string_replace_with_callback: replace ${codes} using a callback that return
+ *                               replacement value (this value must be newly
+ *                               allocated because it will be freed in this
+ *                               function)
+ *                               "errors" is set with number of keys not found
+ *                               by callback
  */
 
 char *
-string_replace_with_hashtable (const char *string,
-                               struct t_hashtable *hashtable,
-                               int *errors)
+string_replace_with_callback (const char *string,
+                              char *(*callback)(void *data, const char *text),
+                              void *callback_data,
+                              int *errors)
 {
     int length, length_value, index_string, index_result;
-    char *result, *result2, *key;
-    const char *pos_end_name, *ptr_value;
+    char *result, *result2, *key, *value;
+    const char *pos_end_name;
 
     *errors = 0;
 
     if (!string)
         return NULL;
 
-    if (!hashtable)
-        return strdup (string);
-
     length = strlen (string) + 1;
     result = malloc (length);
     if (result)
@@ -1820,10 +1820,10 @@ string_replace_with_hashtable (const char *string,
                                           pos_end_name - (string + index_string + 2));
                     if (key)
                     {
-                        ptr_value = (const char *)hashtable_get (hashtable, key);
-                        if (ptr_value)
+                        value = (*callback) (callback_data, key);
+                        if (value)
                         {
-                            length_value = strlen (ptr_value);
+                            length_value = strlen (value);
                             length += length_value;
                             result2 = realloc (result, length);
                             if (!result2)
@@ -1831,13 +1831,15 @@ string_replace_with_hashtable (const char *string,
                                 if (result)
                                     free (result);
                                 free (key);
+                                free (value);
                                 return NULL;
                             }
                             result = result2;
-                            strcpy (result + index_result, ptr_value);
+                            strcpy (result + index_result, value);
                             index_result += length_value;
                             index_string += pos_end_name - string -
                                 index_string + 1;
+                            free (value);
                         }
                         else
                         {
diff --git a/src/core/wee-string.h b/src/core/wee-string.h
index a000e65f3..a9fc76ea8 100644
--- a/src/core/wee-string.h
+++ b/src/core/wee-string.h
@@ -75,8 +75,9 @@ extern void string_encode_base64 (const char *from, int length, char *to);
 extern int string_decode_base64 (const char *from, char *to);
 extern int string_is_command_char (const char *string);
 extern const char *string_input_for_buffer (const char *string);
-extern char *string_replace_with_hashtable (const char *string,
-                                            struct t_hashtable *hashtable,
-                                            int *errors);
+extern char *string_replace_with_callback (const char *string,
+                                           char *(*callback)(void *data, const char *text),
+                                           void *callback_data,
+                                           int *errors);
 
 #endif /* __WEECHAT_STRING_H */
diff --git a/src/gui/gui-bar-item.c b/src/gui/gui-bar-item.c
index fade60939..43d5dbb53 100644
--- a/src/gui/gui-bar-item.c
+++ b/src/gui/gui-bar-item.c
@@ -176,13 +176,52 @@ gui_bar_item_search_with_plugin (struct t_weechat_plugin *plugin,
 }
 
 /*
- * gui_bar_item_used_in_a_bar: return 1 if an item is used in at least one bar
- *                             if partial_name == 1, then search a bar that
- *                             contains item beginning with "item_name"
+ * gui_bar_item_used_in_bar: return 1 if an item is used in the bar
+ *                           if partial_name == 1, then search if an item
+ *                           begins with "item_name"
  */
 
 int
-gui_bar_item_used_in_a_bar (const char *item_name, int partial_name)
+gui_bar_item_used_in_bar (struct t_gui_bar *bar, const char *item_name,
+                          int partial_name)
+{
+    int i, j, length;
+
+    length = strlen (item_name);
+
+    for (i = 0; i < bar->items_count; i++)
+    {
+        for (j = 0; j < bar->items_subcount[i]; j++)
+        {
+            if (bar->items_name[i][j])
+            {
+                if ((partial_name
+                     && strncmp (bar->items_name[i][j],
+                                 item_name, length) == 0)
+                    || (!partial_name
+                        && strcmp (bar->items_name[i][j],
+                                   item_name) == 0))
+                {
+                    return 1;
+                }
+            }
+        }
+    }
+
+    /* item not used in the bar */
+    return 0;
+}
+
+/*
+ * gui_bar_item_used_in_at_least_one_bar: return 1 if an item is used in at
+ *                                        least one bar
+ *                                        if partial_name == 1, then search a
+ *                                        bar that contains item beginning with
+ *                                        "item_name"
+ */
+
+int
+gui_bar_item_used_in_at_least_one_bar (const char *item_name, int partial_name)
 {
     struct t_gui_bar *ptr_bar;
     int i, j, length;
@@ -211,7 +250,7 @@ gui_bar_item_used_in_a_bar (const char *item_name, int partial_name)
         }
     }
 
-    /* item not used by any bar */
+    /* item not used in any bar */
     return 0;
 }
 
diff --git a/src/gui/gui-bar-item.h b/src/gui/gui-bar-item.h
index 2b7b92d6d..8e7ae338d 100644
--- a/src/gui/gui-bar-item.h
+++ b/src/gui/gui-bar-item.h
@@ -76,8 +76,11 @@ extern char *gui_bar_items_default_for_bars[][2];
 
 extern int gui_bar_item_valid (struct t_gui_bar_item *bar_item);
 extern struct t_gui_bar_item *gui_bar_item_search (const char *name);
-extern int gui_bar_item_used_in_a_bar (const char *item_name,
-                                       int partial_name);
+extern int gui_bar_item_used_in_bar (struct t_gui_bar *bar,
+                                     const char *item_name,
+                                     int partial_name);
+extern int gui_bar_item_used_in_at_least_one_bar (const char *item_name,
+                                                  int partial_name);
 extern void gui_bar_item_set_prefix_name_suffix (const char *item_name,
                                                  char **prefix, char **name,
                                                  char **suffix);
diff --git a/src/gui/gui-bar.c b/src/gui/gui-bar.c
index 31ec7f677..eb2c4299c 100644
--- a/src/gui/gui-bar.c
+++ b/src/gui/gui-bar.c
@@ -32,6 +32,8 @@
 
 #include "../core/weechat.h"
 #include "../core/wee-config.h"
+#include "../core/wee-eval.h"
+#include "../core/wee-hashtable.h"
 #include "../core/wee-hdata.h"
 #include "../core/wee-hook.h"
 #include "../core/wee-infolist.h"
@@ -372,27 +374,64 @@ int
 gui_bar_check_conditions_for_window (struct t_gui_bar *bar,
                                      struct t_gui_window *window)
 {
-    int i, rc;
-    char str_modifier[256], str_window[128], *str_displayed;
+    int rc;
+    char str_modifier[256], str_window[128], *str_displayed, *result;
+    const char *conditions;
+    struct t_hashtable *pointers, *extra_vars;
 
-    /* check bar conditions */
-    for (i = 0; i < bar->conditions_count; i++)
+    /* check bar condition(s) */
+    conditions = CONFIG_STRING(bar->options[GUI_BAR_OPTION_CONDITIONS]);
+    if (string_strcasecmp (conditions, "active") == 0)
     {
-        if (string_strcasecmp (bar->conditions_array[i], "active") == 0)
+        if (gui_current_window && (gui_current_window != window))
+            return 0;
+    }
+    else if (string_strcasecmp (conditions, "inactive") == 0)
+    {
+        if (!gui_current_window || (gui_current_window == window))
+            return 0;
+    }
+    else if (string_strcasecmp (conditions, "nicklist") == 0)
+    {
+        if (window->buffer && !window->buffer->nicklist)
+            return 0;
+    }
+    else if (conditions[0])
+    {
+        pointers = hashtable_new (16,
+                                  WEECHAT_HASHTABLE_STRING,
+                                  WEECHAT_HASHTABLE_POINTER,
+                                  NULL,
+                                  NULL);
+        if (pointers)
         {
-            if (gui_current_window && (gui_current_window != window))
-                return 0;
+            hashtable_set (pointers, "window", window);
+            hashtable_set (pointers, "buffer", window->buffer);
         }
-        else if (string_strcasecmp (bar->conditions_array[i], "inactive") == 0)
+        extra_vars = hashtable_new (16,
+                                    WEECHAT_HASHTABLE_STRING,
+                                    WEECHAT_HASHTABLE_POINTER,
+                                    NULL,
+                                    NULL);
+        if (extra_vars)
         {
-            if (!gui_current_window || (gui_current_window == window))
-                return 0;
-        }
-        else if (string_strcasecmp (bar->conditions_array[i], "nicklist") == 0)
-        {
-            if (window->buffer && !window->buffer->nicklist)
-                return 0;
+            hashtable_set (extra_vars, "active",
+                           (gui_current_window && (gui_current_window == window)) ? "1" : "0");
+            hashtable_set (extra_vars, "inactive",
+                           (gui_current_window && (gui_current_window != window)) ? "1" : "0");
+            hashtable_set (extra_vars, "nicklist",
+                           (window->buffer && window->buffer->nicklist) ? "1" : "0");
         }
+        result = eval_expression (conditions, pointers, extra_vars);
+        rc = eval_is_true (result);
+        if (result)
+            free (result);
+        if (pointers)
+            hashtable_free (pointers);
+        if (extra_vars)
+            hashtable_free (extra_vars);
+        if (!rc)
+            return 0;
     }
 
     /*
@@ -413,6 +452,7 @@ gui_bar_check_conditions_for_window (struct t_gui_bar *bar,
         rc = 0;
     else
         rc = 1;
+
     if (str_displayed)
         free (str_displayed);
 
@@ -885,30 +925,9 @@ gui_bar_config_change_priority (void *data, struct t_config_option *option)
 void
 gui_bar_config_change_conditions (void *data, struct t_config_option *option)
 {
-    struct t_gui_bar *ptr_bar;
-
     /* make C compiler happy */
     (void) data;
-
-    ptr_bar = gui_bar_search_with_option_name (option->name);
-    if (ptr_bar)
-    {
-        if (ptr_bar->conditions_array)
-            string_free_split (ptr_bar->conditions_array);
-
-        if (CONFIG_STRING(ptr_bar->options[GUI_BAR_OPTION_CONDITIONS])
-            && CONFIG_STRING(ptr_bar->options[GUI_BAR_OPTION_CONDITIONS])[0])
-        {
-            ptr_bar->conditions_array = string_split (CONFIG_STRING(ptr_bar->options[GUI_BAR_OPTION_CONDITIONS]),
-                                                      ",", 0, 0,
-                                                      &ptr_bar->conditions_count);
-        }
-        else
-        {
-            ptr_bar->conditions_count = 0;
-            ptr_bar->conditions_array = NULL;
-        }
-    }
+    (void) option;
 
     gui_window_ask_refresh (1);
 }
@@ -1343,9 +1362,13 @@ gui_bar_create_option (const char *bar_name, int index_option, const char *value
                     weechat_config_file, weechat_config_section_bar,
                     option_name, "string",
                     N_("condition(s) for displaying bar (for bars of type "
-                       "\"window\"): \"active\" = window must be active, "
-                        "\"inactive\" = window must be inactive, "
-                        "\"nicklist\" = buffer must have a nicklist"),
+                       "\"window\"): a simple condition: \"active\", "
+                       "\"inactive\", \"nicklist\" (window must be active/"
+                       "inactive, buffer must have a nicklist), or an "
+                       "expression with condition(s) (see /help eval), like: "
+                       "\"${nicklist} && ${window.win_width} > 100\" "
+                       "(local variables for expression are ${active}, "
+                       "${inactive} and ${nicklist})"),
                     NULL, 0, 0, value, NULL, 0,
                     NULL, NULL, &gui_bar_config_change_conditions, NULL, NULL, NULL);
                 break;
@@ -1537,8 +1560,6 @@ gui_bar_alloc (const char *name)
         {
             new_bar->options[i] = NULL;
         }
-        new_bar->conditions_count = 0;
-        new_bar->conditions_array = NULL;
         new_bar->items_count = 0;
         new_bar->items_array = NULL;
         new_bar->items_prefix = NULL;
@@ -1585,17 +1606,6 @@ gui_bar_new_with_options (const char *name,
         new_bar->options[GUI_BAR_OPTION_PRIORITY] = priority;
         new_bar->options[GUI_BAR_OPTION_TYPE] = type;
         new_bar->options[GUI_BAR_OPTION_CONDITIONS] = conditions;
-        if (CONFIG_STRING(conditions) && CONFIG_STRING(conditions)[0])
-        {
-            new_bar->conditions_array = string_split (CONFIG_STRING(conditions),
-                                                      ",", 0, 0,
-                                                      &new_bar->conditions_count);
-        }
-        else
-        {
-            new_bar->conditions_count = 0;
-            new_bar->conditions_array = NULL;
-        }
         new_bar->options[GUI_BAR_OPTION_POSITION] = position;
         new_bar->options[GUI_BAR_OPTION_FILLING_TOP_BOTTOM] = filling_top_bottom;
         new_bar->options[GUI_BAR_OPTION_FILLING_LEFT_RIGHT] = filling_left_right;
@@ -1832,7 +1842,7 @@ gui_bar_create_default_input ()
     char *buf;
 
     /* search an input_text item */
-    if (!gui_bar_item_used_in_a_bar (gui_bar_item_names[GUI_BAR_ITEM_INPUT_TEXT], 1))
+    if (!gui_bar_item_used_in_at_least_one_bar (gui_bar_item_names[GUI_BAR_ITEM_INPUT_TEXT], 1))
     {
         ptr_bar = gui_bar_search (GUI_BAR_DEFAULT_NAME_INPUT);
         if (ptr_bar)
@@ -1973,7 +1983,7 @@ gui_bar_create_default_nicklist ()
                          "0",                /* hidden */
                          "200",              /* priority */
                          "window",           /* type */
-                         "nicklist",         /* conditions */
+                         "${nicklist}",      /* conditions */
                          "right",            /* position */
                          "columns_vertical", /* filling_top_bottom */
                          "vertical",         /* filling_left_right */
@@ -2178,8 +2188,6 @@ gui_bar_free (struct t_gui_bar *bar)
         if (bar->options[i])
             config_file_option_free (bar->options[i]);
     }
-    if (bar->conditions_array)
-        string_free_split (bar->conditions_array);
     gui_bar_free_items_arrays (bar);
 
     free (bar);
@@ -2249,8 +2257,6 @@ gui_bar_hdata_bar_cb (void *data, const char *hdata_name)
     {
         HDATA_VAR(struct t_gui_bar, name, STRING, 0, NULL, NULL);
         HDATA_VAR(struct t_gui_bar, options, POINTER, 0, NULL, NULL);
-        HDATA_VAR(struct t_gui_bar, conditions_count, INTEGER, 0, NULL, NULL);
-        HDATA_VAR(struct t_gui_bar, conditions_array, STRING, 0, "conditions_count", NULL);
         HDATA_VAR(struct t_gui_bar, items_count, INTEGER, 0, NULL, NULL);
         HDATA_VAR(struct t_gui_bar, items_subcount, POINTER, 0, NULL, NULL);
         HDATA_VAR(struct t_gui_bar, items_array, POINTER, 0, NULL, NULL);
@@ -2297,16 +2303,6 @@ gui_bar_add_to_infolist (struct t_infolist *infolist,
         return 0;
     if (!infolist_new_var_string (ptr_item, "conditions", CONFIG_STRING(bar->options[GUI_BAR_OPTION_CONDITIONS])))
         return 0;
-    if (!infolist_new_var_integer (ptr_item, "conditions_count", bar->conditions_count))
-        return 0;
-    for (i = 0; i < bar->conditions_count; i++)
-    {
-        snprintf (option_name, sizeof (option_name),
-                  "conditions_array_%05d", i + 1);
-        if (!infolist_new_var_string (ptr_item, option_name,
-                                      bar->conditions_array[i]))
-            return 0;
-    }
     if (!infolist_new_var_integer (ptr_item, "position", CONFIG_INTEGER(bar->options[GUI_BAR_OPTION_POSITION])))
         return 0;
     if (!infolist_new_var_integer (ptr_item, "filling_top_bottom", CONFIG_INTEGER(bar->options[GUI_BAR_OPTION_FILLING_TOP_BOTTOM])))
@@ -2377,8 +2373,6 @@ gui_bar_print_log ()
                     CONFIG_INTEGER(ptr_bar->options[GUI_BAR_OPTION_TYPE]),
                     gui_bar_type_string[CONFIG_INTEGER(ptr_bar->options[GUI_BAR_OPTION_TYPE])]);
         log_printf ("  conditions . . . . . . : '%s'",  CONFIG_STRING(ptr_bar->options[GUI_BAR_OPTION_CONDITIONS]));
-        log_printf ("  conditions_count . . . : %d",    ptr_bar->conditions_count);
-        log_printf ("  conditions_array . . . : 0x%lx", ptr_bar->conditions_array);
         log_printf ("  position . . . . . . . : %d (%s)",
                     CONFIG_INTEGER(ptr_bar->options[GUI_BAR_OPTION_POSITION]),
                     gui_bar_position_string[CONFIG_INTEGER(ptr_bar->options[GUI_BAR_OPTION_POSITION])]);
diff --git a/src/gui/gui-bar.h b/src/gui/gui-bar.h
index aec264129..6743f9fc1 100644
--- a/src/gui/gui-bar.h
+++ b/src/gui/gui-bar.h
@@ -34,7 +34,7 @@ enum t_gui_bar_option
     GUI_BAR_OPTION_HIDDEN = 0,          /* true if bar is hidden            */
     GUI_BAR_OPTION_PRIORITY,            /* bar priority                     */
     GUI_BAR_OPTION_TYPE,                /* type (root or window)            */
-    GUI_BAR_OPTION_CONDITIONS,          /* conditions for display           */
+    GUI_BAR_OPTION_CONDITIONS,          /* condition(s) for display         */
     GUI_BAR_OPTION_POSITION,            /* bottom, top, left, right         */
     GUI_BAR_OPTION_FILLING_TOP_BOTTOM,  /* filling when pos. is top/bottom  */
     GUI_BAR_OPTION_FILLING_LEFT_RIGHT,  /* filling when pos. is left/right  */
@@ -84,8 +84,6 @@ struct t_gui_bar
     struct t_config_option *options[GUI_BAR_NUM_OPTIONS];
 
     /* internal vars */
-    int conditions_count;               /* number of conditions             */
-    char **conditions_array;            /* bar conditions (after split)     */
     int items_count;                    /* number of bar items              */
     int *items_subcount;                /* number of sub items              */
     char ***items_array;                /* bar items (after split)          */
diff --git a/src/gui/gui-key.c b/src/gui/gui-key.c
index 492e0d9e4..93938ec2a 100644
--- a/src/gui/gui-key.c
+++ b/src/gui/gui-key.c
@@ -949,6 +949,29 @@ gui_key_focus_matching (struct t_gui_key *key,
     return match[0] && match[1];
 }
 
+/*
+ * gui_key_focus_command_replace_cb: callback for replacing values in string
+ *                                   with a hashtable
+ */
+
+char *
+gui_key_focus_command_replace_cb (void *data, const char *text)
+{
+    struct t_hashtable *ptr_hashtable;
+    const char *ptr_value;
+
+    ptr_hashtable = (struct t_hashtable *)data;
+
+    if (ptr_hashtable)
+    {
+        ptr_value = hashtable_get (ptr_hashtable, text);
+        if (ptr_value)
+            return strdup (ptr_value);
+    }
+
+    return NULL;
+}
+
 /*
  * gui_key_focus_command: run command according to focus
  *                        return 1 if a command was executed, otherwise 0
@@ -1038,9 +1061,10 @@ gui_key_focus_command (const char *key, int context,
                 }
                 else
                 {
-                    command = string_replace_with_hashtable (commands[i],
-                                                             hashtable,
-                                                             &errors);
+                    command = string_replace_with_callback (commands[i],
+                                                            &gui_key_focus_command_replace_cb,
+                                                            hashtable,
+                                                            &errors);
                     if (command)
                     {
                         if (errors == 0)
diff --git a/src/plugins/guile/weechat-guile-api.c b/src/plugins/guile/weechat-guile-api.c
index 378fb7e0f..f2267b19d 100644
--- a/src/plugins/guile/weechat-guile-api.c
+++ b/src/plugins/guile/weechat-guile-api.c
@@ -420,6 +420,44 @@ weechat_guile_api_string_input_for_buffer (SCM string)
     API_RETURN_STRING(result);
 }
 
+/*
+ * weechat_guile_api_string_eval_expression: evaluate an expression and return
+ *                                           result
+ */
+
+SCM
+weechat_guile_api_string_eval_expression (SCM expr, SCM pointers,
+                                          SCM extra_vars)
+{
+    char *result;
+    SCM return_value;
+    struct t_hashtable *c_pointers, *c_extra_vars;
+
+    API_FUNC(1, "string_eval_expression", API_RETURN_EMPTY);
+    if (!scm_is_string (expr) || !scm_list_p (pointers)
+        || !scm_list_p (extra_vars))
+        API_WRONG_ARGS(API_RETURN_EMPTY);
+
+    c_pointers = weechat_guile_alist_to_hashtable (pointers,
+                                                   WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                   WEECHAT_HASHTABLE_STRING,
+                                                   WEECHAT_HASHTABLE_POINTER);
+    c_extra_vars = weechat_guile_alist_to_hashtable (extra_vars,
+                                                     WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                     WEECHAT_HASHTABLE_STRING,
+                                                     WEECHAT_HASHTABLE_STRING);
+
+    result = weechat_string_eval_expression (scm_i_string_chars (expr),
+                                             c_pointers, c_extra_vars);
+
+    if (c_pointers)
+        weechat_hashtable_free (c_pointers);
+    if (c_extra_vars)
+        weechat_hashtable_free (c_extra_vars);
+
+    API_RETURN_STRING_FREE(result);
+}
+
 /*
  * weechat_guile_api_mkdir_home: create a directory in WeeChat home
  */
@@ -1933,7 +1971,9 @@ weechat_guile_api_key_bind (SCM context, SCM keys)
         API_WRONG_ARGS(API_RETURN_INT(0));
 
     c_keys = weechat_guile_alist_to_hashtable (keys,
-                                               WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                               WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                               WEECHAT_HASHTABLE_STRING,
+                                               WEECHAT_HASHTABLE_STRING);
 
     num_keys = weechat_key_bind (scm_i_string_chars (context), c_keys);
 
@@ -2454,7 +2494,9 @@ weechat_guile_api_hook_process_hashtable (SCM command, SCM options, SCM timeout,
         API_WRONG_ARGS(API_RETURN_EMPTY);
 
     c_options = weechat_guile_alist_to_hashtable (options,
-                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                  WEECHAT_HASHTABLE_STRING,
+                                                  WEECHAT_HASHTABLE_STRING);
 
     result = API_PTR2STR(plugin_script_api_hook_process_hashtable (weechat_guile_plugin,
                                                                    guile_current_script,
@@ -2861,7 +2903,9 @@ weechat_guile_api_hook_hsignal_send (SCM signal, SCM hashtable)
         API_WRONG_ARGS(API_RETURN_ERROR);
 
     c_hashtable = weechat_guile_alist_to_hashtable (hashtable,
-                                                    WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                    WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                    WEECHAT_HASHTABLE_STRING,
+                                                    WEECHAT_HASHTABLE_STRING);
 
     weechat_hook_hsignal_send (scm_i_string_chars (signal), c_hashtable);
 
@@ -4462,7 +4506,9 @@ weechat_guile_api_info_get_hashtable (SCM info_name, SCM hash)
         API_WRONG_ARGS(API_RETURN_EMPTY);
 
     c_hashtable = weechat_guile_alist_to_hashtable (hash,
-                                                    WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                    WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                    WEECHAT_HASHTABLE_STRING,
+                                                    WEECHAT_HASHTABLE_STRING);
 
     result_hashtable = weechat_info_get_hashtable (scm_i_string_chars (info_name),
                                                    c_hashtable);
@@ -5160,7 +5206,9 @@ weechat_guile_api_hdata_update (SCM hdata, SCM pointer, SCM hashtable)
         API_WRONG_ARGS(API_RETURN_INT(0));
 
     c_hashtable = weechat_guile_alist_to_hashtable (hashtable,
-                                                    WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                    WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                    WEECHAT_HASHTABLE_STRING,
+                                                    WEECHAT_HASHTABLE_STRING);
 
     value = weechat_hdata_update (API_STR2PTR(scm_i_string_chars (hdata)),
                                   API_STR2PTR(scm_i_string_chars (pointer)),
@@ -5358,6 +5406,7 @@ weechat_guile_api_module_init (void *data)
     API_DEF_FUNC(string_remove_color, 2);
     API_DEF_FUNC(string_is_command_char, 1);
     API_DEF_FUNC(string_input_for_buffer, 1);
+    API_DEF_FUNC(string_eval_expression, 3);
     API_DEF_FUNC(mkdir_home, 2);
     API_DEF_FUNC(mkdir, 2);
     API_DEF_FUNC(mkdir_parents, 2);
diff --git a/src/plugins/guile/weechat-guile.c b/src/plugins/guile/weechat-guile.c
index 7dbd5ce4b..a46093167 100644
--- a/src/plugins/guile/weechat-guile.c
+++ b/src/plugins/guile/weechat-guile.c
@@ -198,22 +198,21 @@ weechat_guile_hashtable_to_alist (struct t_hashtable *hashtable)
 
 /*
  * weechat_guile_alist_to_hashtable: get WeeChat hashtable with Guile alist
- *                                   Hashtable returned has type string for
- *                                   both keys and values
  *                                   Note: hashtable has to be released after
  *                                   use with call to weechat_hashtable_free()
  */
 
 struct t_hashtable *
-weechat_guile_alist_to_hashtable (SCM alist, int hashtable_size)
+weechat_guile_alist_to_hashtable (SCM alist, int size, const char *type_keys,
+                                  const char *type_values)
 {
     struct t_hashtable *hashtable;
     int length, i;
     SCM pair;
 
-    hashtable = weechat_hashtable_new (hashtable_size,
-                                       WEECHAT_HASHTABLE_STRING,
-                                       WEECHAT_HASHTABLE_STRING,
+    hashtable = weechat_hashtable_new (size,
+                                       type_keys,
+                                       type_values,
                                        NULL,
                                        NULL);
     if (!hashtable)
@@ -223,11 +222,24 @@ weechat_guile_alist_to_hashtable (SCM alist, int hashtable_size)
     for (i = 0; i < length; i++)
     {
         pair = scm_list_ref (alist, scm_from_int (i));
-        weechat_hashtable_set (hashtable,
-                               scm_i_string_chars (scm_list_ref (pair,
-                                                                 scm_from_int (0))),
-                               scm_i_string_chars (scm_list_ref (pair,
-                                                                 scm_from_int (1))));
+        if (strcmp (type_values, WEECHAT_HASHTABLE_STRING) == 0)
+        {
+            weechat_hashtable_set (hashtable,
+                                   scm_i_string_chars (scm_list_ref (pair,
+                                                                     scm_from_int (0))),
+                                   scm_i_string_chars (scm_list_ref (pair,
+                                                                     scm_from_int (1))));
+        }
+        else if (strcmp (type_values, WEECHAT_HASHTABLE_POINTER) == 0)
+        {
+            weechat_hashtable_set (hashtable,
+                                   scm_i_string_chars (scm_list_ref (pair,
+                                                                     scm_from_int (0))),
+                                   plugin_script_str2ptr (weechat_guile_plugin,
+                                                          NULL, NULL,
+                                                          scm_i_string_chars (scm_list_ref (pair,
+                                                                                            scm_from_int (1)))));
+        }
     }
 
     return hashtable;
@@ -305,7 +317,9 @@ weechat_guile_exec (struct t_plugin_script *script,
     else if (ret_type == WEECHAT_SCRIPT_EXEC_HASHTABLE)
     {
         ret_value = weechat_guile_alist_to_hashtable (rc,
-                                                      WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                      WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                      WEECHAT_HASHTABLE_STRING,
+                                                      WEECHAT_HASHTABLE_STRING);
     }
     else
     {
diff --git a/src/plugins/guile/weechat-guile.h b/src/plugins/guile/weechat-guile.h
index b868a4c10..03c104b64 100644
--- a/src/plugins/guile/weechat-guile.h
+++ b/src/plugins/guile/weechat-guile.h
@@ -37,7 +37,9 @@ extern SCM guile_port;
 
 extern SCM weechat_guile_hashtable_to_alist (struct t_hashtable *hashtable);
 extern struct t_hashtable *weechat_guile_alist_to_hashtable (SCM dict,
-                                                             int hashtable_size);
+                                                             int size,
+                                                             const char *type_keys,
+                                                             const char *type_values);
 extern void *weechat_guile_exec (struct t_plugin_script *script,
                                   int ret_type, const char *function,
                                   char *format, void **argv);
diff --git a/src/plugins/lua/weechat-lua-api.c b/src/plugins/lua/weechat-lua-api.c
index ce8a1e61f..6c1f83537 100644
--- a/src/plugins/lua/weechat-lua-api.c
+++ b/src/plugins/lua/weechat-lua-api.c
@@ -460,6 +460,42 @@ weechat_lua_api_string_input_for_buffer (lua_State *L)
     API_RETURN_STRING(result);
 }
 
+/*
+ * weechat_lua_api_string_eval_expression: evaluate an expression and return
+ *                                         result
+ */
+
+static int
+weechat_lua_api_string_eval_expression (lua_State *L)
+{
+    const char *expr;
+    struct t_hashtable *pointers, *extra_vars;
+    char *result;
+
+    API_FUNC(1, "string_eval_expression", API_RETURN_EMPTY);
+    if (lua_gettop (lua_current_interpreter) < 3)
+        API_WRONG_ARGS(API_RETURN_EMPTY);
+
+    expr = lua_tostring (lua_current_interpreter, -3);
+    pointers = weechat_lua_tohashtable (lua_current_interpreter, -2,
+                                        WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                        WEECHAT_HASHTABLE_STRING,
+                                        WEECHAT_HASHTABLE_POINTER);
+    extra_vars = weechat_lua_tohashtable (lua_current_interpreter, -1,
+                                          WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                          WEECHAT_HASHTABLE_STRING,
+                                          WEECHAT_HASHTABLE_STRING);
+
+    result = weechat_string_eval_expression (expr, pointers, extra_vars);
+
+    if (pointers)
+        weechat_hashtable_free (pointers);
+    if (extra_vars)
+        weechat_hashtable_free (extra_vars);
+
+    API_RETURN_STRING_FREE(result);
+}
+
 /*
  * weechat_lua_api_mkdir_home: create a directory in WeeChat home
  */
@@ -2133,7 +2169,9 @@ weechat_lua_api_key_bind (lua_State *L)
 
     context = lua_tostring (lua_current_interpreter, -2);
     hashtable = weechat_lua_tohashtable (lua_current_interpreter, -1,
-                                         WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                         WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                         WEECHAT_HASHTABLE_STRING,
+                                         WEECHAT_HASHTABLE_STRING);
 
     num_keys = weechat_key_bind (context, hashtable);
 
@@ -2702,7 +2740,9 @@ weechat_lua_api_hook_process_hashtable (lua_State *L)
 
     command = lua_tostring (lua_current_interpreter, -5);
     options = weechat_lua_tohashtable (lua_current_interpreter, -4,
-                                       WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                       WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                       WEECHAT_HASHTABLE_STRING,
+                                       WEECHAT_HASHTABLE_STRING);
     timeout = lua_tonumber (lua_current_interpreter, -3);
     function = lua_tostring (lua_current_interpreter, -2);
     data = lua_tostring (lua_current_interpreter, -1);
@@ -3127,7 +3167,9 @@ weechat_lua_api_hook_hsignal_send (lua_State *L)
 
     signal = lua_tostring (lua_current_interpreter, -2);
     hashtable = weechat_lua_tohashtable (lua_current_interpreter, -1,
-                                         WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                         WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                         WEECHAT_HASHTABLE_STRING,
+                                         WEECHAT_HASHTABLE_STRING);
 
     weechat_hook_hsignal_send (signal, hashtable);
 
@@ -4899,7 +4941,9 @@ weechat_lua_api_info_get_hashtable (lua_State *L)
 
     info_name = lua_tostring (lua_current_interpreter, -2);
     table = weechat_lua_tohashtable (lua_current_interpreter, -1,
-                                     WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                     WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                     WEECHAT_HASHTABLE_STRING,
+                                     WEECHAT_HASHTABLE_STRING);
 
     result_hashtable = weechat_info_get_hashtable (info_name, table);
 
@@ -5695,7 +5739,9 @@ weechat_lua_api_hdata_update (lua_State *L)
     hdata = lua_tostring (lua_current_interpreter, -3);
     pointer = lua_tostring (lua_current_interpreter, -2);
     hashtable = weechat_lua_tohashtable (lua_current_interpreter, -1,
-                                         WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                         WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                         WEECHAT_HASHTABLE_STRING,
+                                         WEECHAT_HASHTABLE_STRING);
 
     value = weechat_hdata_update (API_STR2PTR(hdata),
                                   API_STR2PTR(pointer),
@@ -6296,6 +6342,7 @@ const struct luaL_Reg weechat_lua_api_funcs[] = {
     API_DEF_FUNC(string_remove_color),
     API_DEF_FUNC(string_is_command_char),
     API_DEF_FUNC(string_input_for_buffer),
+    API_DEF_FUNC(string_eval_expression),
     API_DEF_FUNC(mkdir_home),
     API_DEF_FUNC(mkdir),
     API_DEF_FUNC(mkdir_parents),
diff --git a/src/plugins/lua/weechat-lua.c b/src/plugins/lua/weechat-lua.c
index 89cede0b8..8711eead1 100644
--- a/src/plugins/lua/weechat-lua.c
+++ b/src/plugins/lua/weechat-lua.c
@@ -108,20 +108,19 @@ weechat_lua_pushhashtable (lua_State *interpreter, struct t_hashtable *hashtable
 
 /*
  * weechat_lua_hash_to_hashtable: get WeeChat hashtable with lua hash (on stack)
- *                                Hashtable returned has type string for
- *                                both keys and values
  *                                Note: hashtable has to be released after use
  *                                with call to weechat_hashtable_free()
  */
 
 struct t_hashtable *
-weechat_lua_tohashtable (lua_State *interpreter, int index, int hashtable_size)
+weechat_lua_tohashtable (lua_State *interpreter, int index, int size,
+                         const char *type_keys, const char *type_values)
 {
     struct t_hashtable *hashtable;
 
-    hashtable = weechat_hashtable_new (hashtable_size,
-                                       WEECHAT_HASHTABLE_STRING,
-                                       WEECHAT_HASHTABLE_STRING,
+    hashtable = weechat_hashtable_new (size,
+                                       type_keys,
+                                       type_values,
                                        NULL,
                                        NULL);
     if (!hashtable)
@@ -130,9 +129,20 @@ weechat_lua_tohashtable (lua_State *interpreter, int index, int hashtable_size)
     lua_pushnil (interpreter);
     while (lua_next (interpreter, index - 1) != 0)
     {
-        weechat_hashtable_set (hashtable,
-                               lua_tostring (interpreter, -2),
-                               lua_tostring (interpreter, -1));
+        if (strcmp (type_values, WEECHAT_HASHTABLE_STRING) == 0)
+        {
+            weechat_hashtable_set (hashtable,
+                                   lua_tostring (interpreter, -2),
+                                   lua_tostring (interpreter, -1));
+        }
+        else if (strcmp (type_values, WEECHAT_HASHTABLE_POINTER) == 0)
+        {
+            weechat_hashtable_set (hashtable,
+                                   lua_tostring (interpreter, -2),
+                                   plugin_script_str2ptr (weechat_lua_plugin,
+                                                          NULL, NULL,
+                                                          lua_tostring (interpreter, -1)));
+        }
         /* remove value from stack (keep key for next iteration) */
         lua_pop (interpreter, 1);
     }
@@ -209,7 +219,9 @@ weechat_lua_exec (struct t_plugin_script *script, int ret_type,
     else if (ret_type == WEECHAT_SCRIPT_EXEC_HASHTABLE)
     {
         ret_value = weechat_lua_tohashtable (lua_current_interpreter, -1,
-                                             WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                             WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                             WEECHAT_HASHTABLE_STRING,
+                                             WEECHAT_HASHTABLE_STRING);
     }
     else
     {
diff --git a/src/plugins/lua/weechat-lua.h b/src/plugins/lua/weechat-lua.h
index 0512d2272..7f4de2085 100644
--- a/src/plugins/lua/weechat-lua.h
+++ b/src/plugins/lua/weechat-lua.h
@@ -40,7 +40,9 @@ extern void weechat_lua_pushhashtable (lua_State *interpreter,
                                        struct t_hashtable *hashtable);
 extern struct t_hashtable *weechat_lua_tohashtable (lua_State *interpreter,
                                                     int index,
-                                                    int hashtable_size);
+                                                    int size,
+                                                    const char *type_keys,
+                                                    const char *type_values);
 extern void *weechat_lua_exec (struct t_plugin_script *script, int ret_type,
                                const char *function,
                                const char *format, void **argv);
diff --git a/src/plugins/perl/weechat-perl-api.c b/src/plugins/perl/weechat-perl-api.c
index 3d0cb645e..d182bbb04 100644
--- a/src/plugins/perl/weechat-perl-api.c
+++ b/src/plugins/perl/weechat-perl-api.c
@@ -436,6 +436,40 @@ XS (XS_weechat_api_string_input_for_buffer)
     API_RETURN_STRING(result);
 }
 
+/*
+ * weechat::string_eval_expression: evaluate expression and return result
+ */
+
+XS (XS_weechat_api_string_eval_expression)
+{
+    char *expr, *result;
+    struct t_hashtable *pointers, *extra_vars;
+    dXSARGS;
+
+    API_FUNC(1, "string_eval_expression", API_RETURN_EMPTY);
+    if (items < 3)
+        API_WRONG_ARGS(API_RETURN_EMPTY);
+
+    expr = SvPV_nolen (ST (0));
+    pointers = weechat_perl_hash_to_hashtable (ST (1),
+                                               WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                               WEECHAT_HASHTABLE_STRING,
+                                               WEECHAT_HASHTABLE_POINTER);
+    extra_vars = weechat_perl_hash_to_hashtable (ST (2),
+                                                 WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                 WEECHAT_HASHTABLE_STRING,
+                                                 WEECHAT_HASHTABLE_STRING);
+
+    result = weechat_string_eval_expression (expr, pointers, extra_vars);
+
+    if (pointers)
+        weechat_hashtable_free (pointers);
+    if (extra_vars)
+        weechat_hashtable_free (extra_vars);
+
+    API_RETURN_STRING_FREE(result);
+}
+
 /*
  * weechat::mkdir_home: create a directory in WeeChat home
  */
@@ -2003,7 +2037,9 @@ XS (XS_weechat_api_key_bind)
 
     context = SvPV_nolen (ST (0));
     hashtable = weechat_perl_hash_to_hashtable (ST (1),
-                                                WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                WEECHAT_HASHTABLE_STRING,
+                                                WEECHAT_HASHTABLE_STRING);
 
     num_keys = weechat_key_bind (context, hashtable);
 
@@ -2537,7 +2573,9 @@ XS (XS_weechat_api_hook_process_hashtable)
 
     command = SvPV_nolen (ST (0));
     options = weechat_perl_hash_to_hashtable (ST (1),
-                                              WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                              WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                              WEECHAT_HASHTABLE_STRING,
+                                              WEECHAT_HASHTABLE_STRING);
     function = SvPV_nolen (ST (3));
     data = SvPV_nolen (ST (4));
 
@@ -2951,7 +2989,9 @@ XS (XS_weechat_api_hook_hsignal_send)
 
     signal = SvPV_nolen (ST (0));
     hashtable = weechat_perl_hash_to_hashtable (ST (1),
-                                                WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                WEECHAT_HASHTABLE_STRING,
+                                                WEECHAT_HASHTABLE_STRING);
 
     weechat_hook_hsignal_send (signal, hashtable);
 
@@ -4663,7 +4703,9 @@ XS (XS_weechat_api_info_get_hashtable)
 
     info_name = SvPV_nolen (ST (0));
     hashtable = weechat_perl_hash_to_hashtable (ST (1),
-                                                WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                WEECHAT_HASHTABLE_STRING,
+                                                WEECHAT_HASHTABLE_STRING);
 
     result_hashtable = weechat_info_get_hashtable (info_name, hashtable);
     result_hash = weechat_perl_hashtable_to_hash (result_hashtable);
@@ -5428,7 +5470,9 @@ XS (XS_weechat_api_hdata_update)
     hdata = SvPV_nolen (ST (0));
     pointer = SvPV_nolen (ST (1));
     hashtable = weechat_perl_hash_to_hashtable (ST (2),
-                                                WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                WEECHAT_HASHTABLE_STRING,
+                                                WEECHAT_HASHTABLE_STRING);
 
     value = weechat_hdata_update (API_STR2PTR(hdata),
                                   API_STR2PTR(pointer),
@@ -5630,6 +5674,7 @@ weechat_perl_api_init (pTHX)
     API_DEF_FUNC(string_remove_color);
     API_DEF_FUNC(string_is_command_char);
     API_DEF_FUNC(string_input_for_buffer);
+    API_DEF_FUNC(string_eval_expression);
     API_DEF_FUNC(mkdir_home);
     API_DEF_FUNC(mkdir);
     API_DEF_FUNC(mkdir_parents);
diff --git a/src/plugins/perl/weechat-perl.c b/src/plugins/perl/weechat-perl.c
index f889aa6be..63ab186bd 100644
--- a/src/plugins/perl/weechat-perl.c
+++ b/src/plugins/perl/weechat-perl.c
@@ -169,14 +169,13 @@ weechat_perl_hashtable_to_hash (struct t_hashtable *hashtable)
 
 /*
  * weechat_perl_hash_to_hashtable: get WeeChat hashtable with perl hash
- *                                 Hashtable returned has type string for
- *                                 both keys and values
  *                                 Note: hashtable has to be released after use
  *                                 with call to weechat_hashtable_free()
  */
 
 struct t_hashtable *
-weechat_perl_hash_to_hashtable (SV *hash, int hashtable_size)
+weechat_perl_hash_to_hashtable (SV *hash, int size, const char *type_keys,
+                                const char *type_values)
 {
     struct t_hashtable *hashtable;
     HV *hash2;
@@ -184,9 +183,9 @@ weechat_perl_hash_to_hashtable (SV *hash, int hashtable_size)
     char *str_key;
     I32 retlen;
 
-    hashtable = weechat_hashtable_new (hashtable_size,
-                                       WEECHAT_HASHTABLE_STRING,
-                                       WEECHAT_HASHTABLE_STRING,
+    hashtable = weechat_hashtable_new (size,
+                                       type_keys,
+                                       type_values,
                                        NULL,
                                        NULL);
     if (!hashtable)
@@ -198,7 +197,15 @@ weechat_perl_hash_to_hashtable (SV *hash, int hashtable_size)
         hv_iterinit (hash2);
         while ((value = hv_iternextsv (hash2, &str_key, &retlen)))
         {
-            weechat_hashtable_set (hashtable, str_key, SvPV (value, PL_na));
+            if (strcmp (type_values, WEECHAT_HASHTABLE_STRING) == 0)
+                weechat_hashtable_set (hashtable, str_key, SvPV (value, PL_na));
+            else if (strcmp (type_values, WEECHAT_HASHTABLE_POINTER) == 0)
+            {
+                weechat_hashtable_set (hashtable, str_key,
+                                       plugin_script_str2ptr (weechat_perl_plugin,
+                                                              NULL, NULL,
+                                                              SvPV (value, PL_na)));
+            }
         }
     }
 
@@ -316,7 +323,9 @@ weechat_perl_exec (struct t_plugin_script *script,
             else if (ret_type == WEECHAT_SCRIPT_EXEC_HASHTABLE)
             {
                 ret_value = weechat_perl_hash_to_hashtable (POPs,
-                                                            WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                            WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                            WEECHAT_HASHTABLE_STRING,
+                                                            WEECHAT_HASHTABLE_STRING);
             }
             else
             {
diff --git a/src/plugins/perl/weechat-perl.h b/src/plugins/perl/weechat-perl.h
index 87a601aac..5e1eabe48 100644
--- a/src/plugins/perl/weechat-perl.h
+++ b/src/plugins/perl/weechat-perl.h
@@ -35,8 +35,9 @@ extern struct t_plugin_script *perl_registered_script;
 extern const char *perl_current_script_filename;
 
 extern HV *weechat_perl_hashtable_to_hash (struct t_hashtable *hashtable);
-extern struct t_hashtable *weechat_perl_hash_to_hashtable (SV *hash,
-                                                           int hashtable_size);
+extern struct t_hashtable *weechat_perl_hash_to_hashtable (SV *hash, int size,
+                                                           const char *type_keys,
+                                                           const char *type_values);
 extern void *weechat_perl_exec (struct t_plugin_script *script,
                                 int ret_type, const char *function,
                                 const char *format, void **argv);
diff --git a/src/plugins/plugin-script.c b/src/plugins/plugin-script.c
index b1df0f49d..bc2babc49 100644
--- a/src/plugins/plugin-script.c
+++ b/src/plugins/plugin-script.c
@@ -286,7 +286,7 @@ plugin_script_str2ptr (struct t_weechat_plugin *weechat_plugin,
         return (void *)value;
 
 invalid:
-    if (weechat_plugin->debug >= 1)
+    if ((weechat_plugin->debug >= 1) && script_name && function_name)
     {
         ptr_buffer = weechat_buffer_search_main ();
         if (ptr_buffer)
diff --git a/src/plugins/plugin.c b/src/plugins/plugin.c
index 323e5068b..dfec3a14c 100644
--- a/src/plugins/plugin.c
+++ b/src/plugins/plugin.c
@@ -39,6 +39,7 @@
 
 #include "../core/weechat.h"
 #include "../core/wee-config.h"
+#include "../core/wee-eval.h"
 #include "../core/wee-hashtable.h"
 #include "../core/wee-hdata.h"
 #include "../core/wee-hook.h"
@@ -521,6 +522,7 @@ plugin_load (const char *filename, int argc, char **argv)
         new_plugin->string_decode_base64 = &string_decode_base64;
         new_plugin->string_is_command_char = &string_is_command_char;
         new_plugin->string_input_for_buffer = &string_input_for_buffer;
+        new_plugin->string_eval_expression = &eval_expression;
 
         new_plugin->utf8_has_8bits = &utf8_has_8bits;
         new_plugin->utf8_is_valid = &utf8_is_valid;
diff --git a/src/plugins/python/weechat-python-api.c b/src/plugins/python/weechat-python-api.c
index cc8f2a4e1..f450f556b 100644
--- a/src/plugins/python/weechat-python-api.c
+++ b/src/plugins/python/weechat-python-api.c
@@ -443,6 +443,43 @@ weechat_python_api_string_input_for_buffer (PyObject *self, PyObject *args)
     API_RETURN_STRING(result);
 }
 
+/*
+ * weechat_python_api_string_eval_expression: evaluate expression and return
+ *                                            result
+ */
+
+static PyObject *
+weechat_python_api_string_eval_expression (PyObject *self, PyObject *args)
+{
+    char *expr, *result;
+    struct t_hashtable *pointers, *extra_vars;
+    PyObject *dict, *dict2, *return_value;
+
+    API_FUNC(1, "string_eval_expression", API_RETURN_EMPTY);
+    expr = NULL;
+    pointers = NULL;
+    extra_vars = NULL;
+    if (!PyArg_ParseTuple (args, "sOO", &expr, &dict, &dict2))
+        API_WRONG_ARGS(API_RETURN_EMPTY);
+    pointers = weechat_python_dict_to_hashtable (dict,
+                                                 WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                 WEECHAT_HASHTABLE_STRING,
+                                                 WEECHAT_HASHTABLE_POINTER);
+    extra_vars = weechat_python_dict_to_hashtable (dict2,
+                                                   WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                   WEECHAT_HASHTABLE_STRING,
+                                                   WEECHAT_HASHTABLE_STRING);
+
+    result = weechat_string_eval_expression (expr, pointers, extra_vars);
+
+    if (pointers)
+        weechat_hashtable_free (pointers);
+    if (extra_vars)
+        weechat_hashtable_free (extra_vars);
+
+    API_RETURN_STRING_FREE(result);
+}
+
 /*
  * weechat_python_api_mkdir_home: create a directory in WeeChat home
  */
@@ -2081,7 +2118,9 @@ weechat_python_api_key_bind (PyObject *self, PyObject *args)
         API_WRONG_ARGS(API_RETURN_INT(0));
 
     hashtable = weechat_python_dict_to_hashtable (dict,
-                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                  WEECHAT_HASHTABLE_STRING,
+                                                  WEECHAT_HASHTABLE_STRING);
 
     num_keys = weechat_key_bind (context, hashtable);
 
@@ -2652,7 +2691,9 @@ weechat_python_api_hook_process_hashtable (PyObject *self, PyObject *args)
                            &data))
         API_WRONG_ARGS(API_RETURN_EMPTY);
     options = weechat_python_dict_to_hashtable (dict,
-                                                WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                WEECHAT_HASHTABLE_STRING,
+                                                WEECHAT_HASHTABLE_STRING);
 
     result = API_PTR2STR(plugin_script_api_hook_process_hashtable (weechat_python_plugin,
                                                                    python_current_script,
@@ -3077,7 +3118,9 @@ weechat_python_api_hook_hsignal_send (PyObject *self, PyObject *args)
         API_WRONG_ARGS(API_RETURN_ERROR);
 
     hashtable = weechat_python_dict_to_hashtable (dict,
-                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                  WEECHAT_HASHTABLE_STRING,
+                                                  WEECHAT_HASHTABLE_STRING);
 
     weechat_hook_hsignal_send (signal, hashtable);
 
@@ -4840,7 +4883,9 @@ weechat_python_api_info_get_hashtable (PyObject *self, PyObject *args)
     if (!PyArg_ParseTuple (args, "sO", &info_name, &dict))
         API_WRONG_ARGS(API_RETURN_EMPTY);
     hashtable = weechat_python_dict_to_hashtable (dict,
-                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                  WEECHAT_HASHTABLE_STRING,
+                                                  WEECHAT_HASHTABLE_STRING);
 
     result_hashtable = weechat_info_get_hashtable (info_name, hashtable);
     result_dict = weechat_python_hashtable_to_dict (result_hashtable);
@@ -5613,7 +5658,9 @@ weechat_python_api_hdata_update (PyObject *self, PyObject *args)
     if (!PyArg_ParseTuple (args, "ssO", &hdata, &pointer, &dict))
         API_WRONG_ARGS(API_RETURN_INT(0));
     hashtable = weechat_python_dict_to_hashtable (dict,
-                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                  WEECHAT_HASHTABLE_STRING,
+                                                  WEECHAT_HASHTABLE_STRING);
 
     value = weechat_hdata_update (API_STR2PTR(hdata),
                                   API_STR2PTR(pointer),
@@ -5807,6 +5854,7 @@ PyMethodDef weechat_python_funcs[] =
     API_DEF_FUNC(string_remove_color),
     API_DEF_FUNC(string_is_command_char),
     API_DEF_FUNC(string_input_for_buffer),
+    API_DEF_FUNC(string_eval_expression),
     API_DEF_FUNC(mkdir_home),
     API_DEF_FUNC(mkdir),
     API_DEF_FUNC(mkdir_parents),
diff --git a/src/plugins/python/weechat-python.c b/src/plugins/python/weechat-python.c
index 2eba42de4..d1a6d4185 100644
--- a/src/plugins/python/weechat-python.c
+++ b/src/plugins/python/weechat-python.c
@@ -232,23 +232,23 @@ weechat_python_hashtable_to_dict (struct t_hashtable *hashtable)
 /*
  * weechat_python_dict_to_hashtable: get WeeChat hashtable with python
  *                                   dictionary
- *                                   Hashtable returned has type string for
- *                                   both keys and values
  *                                   Note: hashtable has to be released after
  *                                   use with call to weechat_hashtable_free()
  */
 
 struct t_hashtable *
-weechat_python_dict_to_hashtable (PyObject *dict, int hashtable_size)
+weechat_python_dict_to_hashtable (PyObject *dict, int size,
+                                  const char *type_keys,
+                                  const char *type_values)
 {
     struct t_hashtable *hashtable;
     PyObject *key, *value;
     Py_ssize_t pos;
     char *str_key, *str_value;
 
-    hashtable = weechat_hashtable_new (hashtable_size,
-                                       WEECHAT_HASHTABLE_STRING,
-                                       WEECHAT_HASHTABLE_STRING,
+    hashtable = weechat_hashtable_new (size,
+                                       type_keys,
+                                       type_values,
                                        NULL,
                                        NULL);
     if (!hashtable)
@@ -275,7 +275,17 @@ weechat_python_dict_to_hashtable (PyObject *dict, int hashtable_size)
             str_value = weechat_python_unicode_to_string (value);
 
         if (str_key)
-            weechat_hashtable_set (hashtable, str_key, str_value);
+        {
+            if (strcmp (type_values, WEECHAT_HASHTABLE_STRING) == 0)
+                weechat_hashtable_set (hashtable, str_key, str_value);
+            else if (strcmp (type_values, WEECHAT_HASHTABLE_POINTER) == 0)
+            {
+                weechat_hashtable_set (hashtable, str_key,
+                                       plugin_script_str2ptr (weechat_python_plugin,
+                                                              NULL, NULL,
+                                                              str_value));
+            }
+        }
 
         if (str_key)
             free (str_key);
@@ -388,7 +398,9 @@ weechat_python_exec (struct t_plugin_script *script,
     else if (ret_type == WEECHAT_SCRIPT_EXEC_HASHTABLE)
     {
         ret_value = weechat_python_dict_to_hashtable (rc,
-                                                      WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                      WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                      WEECHAT_HASHTABLE_STRING,
+                                                      WEECHAT_HASHTABLE_STRING);
         Py_XDECREF(rc);
     }
     else
diff --git a/src/plugins/python/weechat-python.h b/src/plugins/python/weechat-python.h
index 1a522603a..0a1aa2fe5 100644
--- a/src/plugins/python/weechat-python.h
+++ b/src/plugins/python/weechat-python.h
@@ -45,7 +45,9 @@ extern const char *python_current_script_filename;
 
 extern PyObject *weechat_python_hashtable_to_dict (struct t_hashtable *hashtable);
 extern struct t_hashtable *weechat_python_dict_to_hashtable (PyObject *dict,
-                                                             int hashtable_size);
+                                                             int size,
+                                                             const char *type_keys,
+                                                             const char *type_values);
 extern void *weechat_python_exec (struct t_plugin_script *script,
                                   int ret_type, const char *function,
                                   char *format, void **argv);
diff --git a/src/plugins/ruby/weechat-ruby-api.c b/src/plugins/ruby/weechat-ruby-api.c
index 23420282e..a0911bfe9 100644
--- a/src/plugins/ruby/weechat-ruby-api.c
+++ b/src/plugins/ruby/weechat-ruby-api.c
@@ -507,6 +507,47 @@ weechat_ruby_api_string_input_for_buffer (VALUE class, VALUE string)
     API_RETURN_STRING(result);
 }
 
+/*
+ * weechat_ruby_api_string_eval_expression: evaluate an expression and return
+ *                                          result
+ */
+
+static VALUE
+weechat_ruby_api_string_eval_expression (VALUE class, VALUE expr,
+                                         VALUE pointers, VALUE extra_vars)
+{
+    char *c_expr, *result;
+    struct t_hashtable *c_pointers, *c_extra_vars;
+    VALUE return_value;
+
+    API_FUNC(1, "string_eval_expression", API_RETURN_EMPTY);
+    if (NIL_P (expr) || NIL_P (pointers) || NIL_P (extra_vars))
+        API_WRONG_ARGS(API_RETURN_EMPTY);
+
+    Check_Type (expr, T_STRING);
+    Check_Type (pointers, T_HASH);
+    Check_Type (extra_vars, T_HASH);
+
+    c_expr = StringValuePtr (expr);
+    c_pointers = weechat_ruby_hash_to_hashtable (pointers,
+                                                 WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                 WEECHAT_HASHTABLE_STRING,
+                                                 WEECHAT_HASHTABLE_POINTER);
+    c_extra_vars = weechat_ruby_hash_to_hashtable (extra_vars,
+                                                   WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                   WEECHAT_HASHTABLE_STRING,
+                                                   WEECHAT_HASHTABLE_STRING);
+
+    result = weechat_string_eval_expression (c_expr, c_pointers, c_extra_vars);
+
+    if (c_pointers)
+        weechat_hashtable_free (c_pointers);
+    if (c_extra_vars)
+        weechat_hashtable_free (c_extra_vars);
+
+    API_RETURN_STRING_FREE(result);
+}
+
 /*
  * weechat_ruby_api_mkdir_home: create a directory in WeeChat home
  */
@@ -2389,7 +2430,9 @@ weechat_ruby_api_key_bind (VALUE class, VALUE context, VALUE keys)
 
     c_context = StringValuePtr (context);
     c_keys = weechat_ruby_hash_to_hashtable (keys,
-                                             WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                             WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                             WEECHAT_HASHTABLE_STRING,
+                                             WEECHAT_HASHTABLE_STRING);
 
     num_keys = weechat_key_bind (c_context, c_keys);
 
@@ -3031,7 +3074,9 @@ weechat_ruby_api_hook_process_hashtable (VALUE class, VALUE command,
 
     c_command = StringValuePtr (command);
     c_options = weechat_ruby_hash_to_hashtable (options,
-                                                WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                WEECHAT_HASHTABLE_STRING,
+                                                WEECHAT_HASHTABLE_STRING);
     c_timeout = FIX2INT (timeout);
     c_function = StringValuePtr (function);
     c_data = StringValuePtr (data);
@@ -3498,7 +3543,9 @@ weechat_ruby_api_hook_hsignal_send (VALUE class, VALUE signal, VALUE hashtable)
 
     c_signal = StringValuePtr (signal);
     c_hashtable = weechat_ruby_hash_to_hashtable (hashtable,
-                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                  WEECHAT_HASHTABLE_STRING,
+                                                  WEECHAT_HASHTABLE_STRING);
 
     weechat_hook_hsignal_send (c_signal, c_hashtable);
 
@@ -5543,7 +5590,9 @@ weechat_ruby_api_info_get_hashtable (VALUE class, VALUE info_name,
 
     c_info_name = StringValuePtr (info_name);
     c_hashtable = weechat_ruby_hash_to_hashtable (hash,
-                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                  WEECHAT_HASHTABLE_STRING,
+                                                  WEECHAT_HASHTABLE_STRING);
 
     result_hashtable = weechat_info_get_hashtable (c_info_name, c_hashtable);
     result_hash = weechat_ruby_hashtable_to_hash (result_hashtable);
@@ -6465,7 +6514,9 @@ weechat_ruby_api_hdata_update (VALUE class, VALUE hdata, VALUE pointer,
     c_hdata = StringValuePtr (hdata);
     c_pointer = StringValuePtr (pointer);
     c_hashtable = weechat_ruby_hash_to_hashtable (hashtable,
-                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                  WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                  WEECHAT_HASHTABLE_STRING,
+                                                  WEECHAT_HASHTABLE_STRING);
 
     value = weechat_hdata_update (API_STR2PTR(c_hdata),
                                   API_STR2PTR(c_pointer),
@@ -6732,6 +6783,7 @@ weechat_ruby_api_init (VALUE ruby_mWeechat)
     API_DEF_FUNC(string_remove_color, 2);
     API_DEF_FUNC(string_is_command_char, 1);
     API_DEF_FUNC(string_input_for_buffer, 1);
+    API_DEF_FUNC(string_eval_expression, 3);
     API_DEF_FUNC(mkdir_home, 2);
     API_DEF_FUNC(mkdir, 2);
     API_DEF_FUNC(mkdir_parents, 2);
diff --git a/src/plugins/ruby/weechat-ruby.c b/src/plugins/ruby/weechat-ruby.c
index 882796d7d..e2b68db58 100644
--- a/src/plugins/ruby/weechat-ruby.c
+++ b/src/plugins/ruby/weechat-ruby.c
@@ -147,32 +147,43 @@ int
 weechat_ruby_hash_foreach_cb (VALUE key, VALUE value, void *arg)
 {
     struct t_hashtable *hashtable;
+    const char *type_values;
 
     hashtable = (struct t_hashtable *)arg;
     if ((TYPE(key) == T_STRING) && (TYPE(value) == T_STRING))
     {
-        weechat_hashtable_set (hashtable, StringValuePtr(key),
-                               StringValuePtr(value));
+        type_values = weechat_hashtable_get_string (hashtable, "type_values");
+        if (strcmp (type_values, WEECHAT_HASHTABLE_STRING) == 0)
+        {
+            weechat_hashtable_set (hashtable, StringValuePtr(key),
+                                   StringValuePtr(value));
+        }
+        else if (strcmp (type_values, WEECHAT_HASHTABLE_POINTER) == 0)
+        {
+            weechat_hashtable_set (hashtable, StringValuePtr(key),
+                                   plugin_script_str2ptr (weechat_ruby_plugin,
+                                                          NULL, NULL,
+                                                          StringValuePtr(value)));
+        }
     }
     return 0;
 }
 
 /*
  * weechat_ruby_hash_to_hashtable: get WeeChat hashtable with ruby hashtable
- *                                 Hashtable returned has type string for
- *                                 both keys and values
  *                                 Note: hashtable has to be released after use
  *                                 with call to weechat_hashtable_free()
  */
 
 struct t_hashtable *
-weechat_ruby_hash_to_hashtable (VALUE hash, int hashtable_size)
+weechat_ruby_hash_to_hashtable (VALUE hash, int size, const char *type_keys,
+                                const char *type_values)
 {
     struct t_hashtable *hashtable;
 
-    hashtable = weechat_hashtable_new (hashtable_size,
-                                       WEECHAT_HASHTABLE_STRING,
-                                       WEECHAT_HASHTABLE_STRING,
+    hashtable = weechat_hashtable_new (size,
+                                       type_keys,
+                                       type_values,
                                        NULL,
                                        NULL);
     if (!hashtable)
@@ -375,7 +386,9 @@ weechat_ruby_exec (struct t_plugin_script *script,
     else if (ret_type == WEECHAT_SCRIPT_EXEC_HASHTABLE)
     {
         ret_value = weechat_ruby_hash_to_hashtable (rc,
-                                                    WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                    WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                    WEECHAT_HASHTABLE_STRING,
+                                                    WEECHAT_HASHTABLE_STRING);
     }
     else
     {
diff --git a/src/plugins/ruby/weechat-ruby.h b/src/plugins/ruby/weechat-ruby.h
index cf3e7a1b2..398616afa 100644
--- a/src/plugins/ruby/weechat-ruby.h
+++ b/src/plugins/ruby/weechat-ruby.h
@@ -37,7 +37,9 @@ extern const char *ruby_current_script_filename;
 
 extern VALUE weechat_ruby_hashtable_to_hash (struct t_hashtable *hashtable);
 extern struct t_hashtable *weechat_ruby_hash_to_hashtable (VALUE dict,
-                                                           int hashtable_size);
+                                                           int size,
+                                                           const char *type_keys,
+                                                           const char *type_values);
 void *weechat_ruby_exec (struct t_plugin_script *script,
                          int ret_type, const char *function,
                          const char *format, void **argv);
diff --git a/src/plugins/tcl/weechat-tcl-api.c b/src/plugins/tcl/weechat-tcl-api.c
index 0738fc39e..5e89aa3f3 100644
--- a/src/plugins/tcl/weechat-tcl-api.c
+++ b/src/plugins/tcl/weechat-tcl-api.c
@@ -611,6 +611,45 @@ weechat_tcl_api_string_input_for_buffer (ClientData clientData, Tcl_Interp *inte
     API_RETURN_STRING(result);
 }
 
+/*
+ * weechat_tcl_api_string_eval_expression: evaluate an expression and return
+ *                                         result
+ */
+
+static int
+weechat_tcl_api_string_eval_expression (ClientData clientData,
+                                        Tcl_Interp *interp,
+                                        int objc, Tcl_Obj *CONST objv[])
+{
+    Tcl_Obj *objp;
+    char *expr, *result;
+    struct t_hashtable *pointers, *extra_vars;
+    int i;
+
+    API_FUNC(1, "string_eval_expression", API_RETURN_EMPTY);
+    if (objc < 4)
+        API_WRONG_ARGS(API_RETURN_EMPTY);
+
+    expr = Tcl_GetStringFromObj (objv[1], &i);
+    pointers = weechat_tcl_dict_to_hashtable (interp, objv[2],
+                                              WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                              WEECHAT_HASHTABLE_STRING,
+                                              WEECHAT_HASHTABLE_POINTER);
+    extra_vars = weechat_tcl_dict_to_hashtable (interp, objv[3],
+                                                WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                WEECHAT_HASHTABLE_STRING,
+                                                WEECHAT_HASHTABLE_STRING);
+
+    result = weechat_string_eval_expression (expr, pointers, extra_vars);
+
+    if (pointers)
+        weechat_hashtable_free (pointers);
+    if (extra_vars)
+        weechat_hashtable_free (extra_vars);
+
+    API_RETURN_STRING_FREE(result);
+}
+
 /*
  * weechat_tcl_api_mkdir_home: create a directory in WeeChat home
  */
@@ -2372,7 +2411,9 @@ weechat_tcl_api_key_bind (ClientData clientData, Tcl_Interp *interp,
 
     context = Tcl_GetStringFromObj (objv[1], &i);
     hashtable = weechat_tcl_dict_to_hashtable (interp, objv[2],
-                                               WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                               WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                               WEECHAT_HASHTABLE_STRING,
+                                               WEECHAT_HASHTABLE_STRING);
 
     num_keys = weechat_key_bind (context, hashtable);
 
@@ -2973,7 +3014,9 @@ weechat_tcl_api_hook_process_hashtable (ClientData clientData,
 
     command = Tcl_GetStringFromObj (objv[1], &i);
     options = weechat_tcl_dict_to_hashtable (interp, objv[2],
-                                             WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                             WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                             WEECHAT_HASHTABLE_STRING,
+                                             WEECHAT_HASHTABLE_STRING);
     function = Tcl_GetStringFromObj (objv[4], &i);
     data = Tcl_GetStringFromObj (objv[5], &i);
 
@@ -3416,7 +3459,9 @@ weechat_tcl_api_hook_hsignal_send (ClientData clientData, Tcl_Interp *interp,
 
     signal = Tcl_GetStringFromObj (objv[1], &i);
     hashtable = weechat_tcl_dict_to_hashtable (interp, objv[2],
-                                               WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                               WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                               WEECHAT_HASHTABLE_STRING,
+                                               WEECHAT_HASHTABLE_STRING);
 
     weechat_hook_hsignal_send (signal, hashtable);
 
@@ -5320,7 +5365,9 @@ weechat_tcl_api_info_get_hashtable (ClientData clientData, Tcl_Interp *interp,
         API_WRONG_ARGS(API_RETURN_EMPTY);
 
     hashtable = weechat_tcl_dict_to_hashtable (interp, objv[2],
-                                               WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                               WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                               WEECHAT_HASHTABLE_STRING,
+                                               WEECHAT_HASHTABLE_STRING);
 
     result_hashtable = weechat_info_get_hashtable (Tcl_GetStringFromObj (objv[1], &i),
                                                    hashtable);
@@ -6178,7 +6225,9 @@ weechat_tcl_api_hdata_update (ClientData clientData, Tcl_Interp *interp,
     hdata = Tcl_GetStringFromObj (objv[1], &i);
     pointer = Tcl_GetStringFromObj (objv[2], &i);
     hashtable = weechat_tcl_dict_to_hashtable (interp, objv[3],
-                                               WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                               WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                               WEECHAT_HASHTABLE_STRING,
+                                               WEECHAT_HASHTABLE_STRING);
 
     value = weechat_hdata_update (API_STR2PTR(hdata),
                                   API_STR2PTR(pointer),
@@ -6495,6 +6544,7 @@ void weechat_tcl_api_init (Tcl_Interp *interp)
     API_DEF_FUNC(string_remove_color);
     API_DEF_FUNC(string_is_command_char);
     API_DEF_FUNC(string_input_for_buffer);
+    API_DEF_FUNC(string_eval_expression);
     API_DEF_FUNC(mkdir_home);
     API_DEF_FUNC(mkdir);
     API_DEF_FUNC(mkdir_parents);
diff --git a/src/plugins/tcl/weechat-tcl.c b/src/plugins/tcl/weechat-tcl.c
index 26095c467..95a55fe71 100644
--- a/src/plugins/tcl/weechat-tcl.c
+++ b/src/plugins/tcl/weechat-tcl.c
@@ -125,24 +125,23 @@ weechat_tcl_hashtable_to_dict (Tcl_Interp *interp,
 
 /*
  * weechat_tcl_dict_to_hashtable: get WeeChat hashtable with tcl dict
- *                                Hashtable returned has type string for
- *                                both keys and values
  *                                Note: hashtable has to be released after
  *                                use with call to weechat_hashtable_free()
  */
 
 struct t_hashtable *
 weechat_tcl_dict_to_hashtable (Tcl_Interp *interp, Tcl_Obj *dict,
-                               int hashtable_size)
+                               int size, const char *type_keys,
+                               const char *type_values)
 {
     struct t_hashtable *hashtable;
     Tcl_DictSearch search;
     Tcl_Obj *key, *value;
     int done;
 
-    hashtable = weechat_hashtable_new (hashtable_size,
-                                       WEECHAT_HASHTABLE_STRING,
-                                       WEECHAT_HASHTABLE_STRING,
+    hashtable = weechat_hashtable_new (size,
+                                       type_keys,
+                                       type_values,
                                        NULL,
                                        NULL);
     if (!hashtable)
@@ -152,9 +151,20 @@ weechat_tcl_dict_to_hashtable (Tcl_Interp *interp, Tcl_Obj *dict,
     {
         for (; !done ; Tcl_DictObjNext(&search, &key, &value, &done))
         {
-            weechat_hashtable_set (hashtable,
-                                   Tcl_GetString (key),
-                                   Tcl_GetString (value));
+            if (strcmp (type_values, WEECHAT_HASHTABLE_STRING) == 0)
+            {
+                weechat_hashtable_set (hashtable,
+                                       Tcl_GetString (key),
+                                       Tcl_GetString (value));
+            }
+            else if (strcmp (type_values, WEECHAT_HASHTABLE_POINTER) == 0)
+            {
+                weechat_hashtable_set (hashtable,
+                                       Tcl_GetString (key),
+                                       plugin_script_str2ptr (weechat_tcl_plugin,
+                                                              NULL, NULL,
+                                                              Tcl_GetString (value)));
+            }
         }
     }
     Tcl_DictObjDone(&search);
@@ -246,7 +256,9 @@ weechat_tcl_exec (struct t_plugin_script *script,
         {
             ret_val = weechat_tcl_dict_to_hashtable (interp,
                                                      Tcl_GetObjResult (interp),
-                                                     WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE);
+                                                     WEECHAT_SCRIPT_HASHTABLE_DEFAULT_SIZE,
+                                                     WEECHAT_HASHTABLE_STRING,
+                                                     WEECHAT_HASHTABLE_STRING);
         }
 
         tcl_current_script = old_tcl_script;
diff --git a/src/plugins/tcl/weechat-tcl.h b/src/plugins/tcl/weechat-tcl.h
index 62a258885..65453fc83 100644
--- a/src/plugins/tcl/weechat-tcl.h
+++ b/src/plugins/tcl/weechat-tcl.h
@@ -39,7 +39,9 @@ extern Tcl_Obj *weechat_tcl_hashtable_to_dict (Tcl_Interp *interp,
                                                struct t_hashtable *hashtable);
 extern struct t_hashtable *weechat_tcl_dict_to_hashtable (Tcl_Interp *interp,
                                                           Tcl_Obj *dict,
-                                                          int hashtable_size);
+                                                          int size,
+                                                          const char *type_keys,
+                                                          const char *type_values);
 extern void *weechat_tcl_exec (struct t_plugin_script *script,
                                int ret_type, const char *function,
                                const char *format, void **argv);
diff --git a/src/plugins/weechat-plugin.h b/src/plugins/weechat-plugin.h
index b70c75de4..8b55e560c 100644
--- a/src/plugins/weechat-plugin.h
+++ b/src/plugins/weechat-plugin.h
@@ -50,7 +50,7 @@ struct timeval;
  * please change the date with current one; for a second change at same
  * date, increment the 01, otherwise please keep 01.
  */
-#define WEECHAT_PLUGIN_API_VERSION "20121014-01"
+#define WEECHAT_PLUGIN_API_VERSION "20121102-01"
 
 /* macros for defining plugin infos */
 #define WEECHAT_PLUGIN_NAME(__name)                                     \
@@ -251,6 +251,9 @@ struct t_weechat_plugin
     int (*string_decode_base64) (const char *from, char *to);
     int (*string_is_command_char) (const char *string);
     const char *(*string_input_for_buffer) (const char *string);
+    char *(*string_eval_expression )(const char *expr,
+                                     struct t_hashtable *pointers,
+                                     struct t_hashtable *extra_vars);
 
     /* UTF-8 strings */
     int (*utf8_has_8bits) (const char *string);
@@ -1009,6 +1012,10 @@ extern int weechat_plugin_end (struct t_weechat_plugin *plugin);
     weechat_plugin->string_is_command_char(__string)
 #define weechat_string_input_for_buffer(__string)                       \
     weechat_plugin->string_input_for_buffer(__string)
+#define weechat_string_eval_expression(__expr, __pointers,              \
+                                       __extra_vars)                    \
+    weechat_plugin->string_eval_expression(__expr, __pointers,          \
+                                           __extra_vars)                \
 
 /* UTF-8 strings */
 #define weechat_utf8_has_8bits(__string)                                \