core: add calculation of expression in evaluation of expressions with "calc:..." (issue #997)

2026-07-09 11:13:12 +02:00 · 2019-09-20 21:37:01 +02:00
parent 0109c51937
commit 997894edc0
40 changed files with 903 additions and 244 deletions
@@ -25,6 +25,7 @@ Bug fixes::

 New features::

+  * core: add calculation of expression in evaluation of expressions with "calc:..." (issue #997)
  * script: add options "-ol" and "-il" in command /script to send translated string with list of scripts loaded, display "No scripts loaded" if no scripts are loaded

 Build::
@@ -266,65 +266,66 @@ infolists: zeigt Information über die Infolists an
 /eval  [-n|-s] <expression>
       [-n] -c <expression1> <operator> <expression2>

-        -n: gibt das Ergebnis aus, ohne das dieses in den Buffer gesendet wird (debug Modus)
-        -s: teilt Ausdrücke bevor sie evaluiert werden (mehrere Befehle können durch Semikolon getrennt werden)
-        -c: Auswertung als Bedingung: nutzt Operatoren und runde Klammern, Rückgabewert als Boolean-Wert ("0" oder "1")
-expression: Ausdruck welcher verarbeitet werden soll. Variablen im Format ${variable} werden ersetzt (siehe unten); mehrere Befehle werden durch ein Semikolon voneinander getrennt
-  operator: ein logischer oder vergleichender Operand:
-            - logische Operanden:
-                &&  boolean "und"
-                ||  boolean "oder"
-            - vergleichende Operanden:
-                ==  gleich
-                !=  ungleich
-                <=  kleiner oder gleich
-                <   kleiner
-                >=  größer oder gleich
-                >   größer
-                =~  stimmt mit regulärem POSIX Ausdruck überein
-                !~  stimmt NICHT mit regulärem POSIX Ausdruck überein
-                =*  stimmt mit Maske überein (Platzhalter "*" ist erlaubt)
-                !*  stimmt mit Maske NICHT überein (Platzhalter "*" ist erlaubt)
+        -n: display result without sending it to buffer (debug mode)
+        -s: split expression before evaluating it (many commands can be separated by semicolons)
+        -c: evaluate as condition: use operators and parentheses, return a boolean value ("0" or "1")
+expression: expression to evaluate, variables with format ${variable} are replaced (see below); many commands can be separated by semicolons
+  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 POSIX extended regex
+                !~  is NOT matching POSIX extended regex
+                =*  is matching mask (wildcard "*" is allowed)
+                !*  is NOT matching mask (wildcard "*" is allowed)

-Ein Ausdruck gilt als "wahr" sofern das Ergebnis weder NULL, nicht leer und von "0" abweichend ist.
-Für einen Vergleich werden Fließkommazahlen genutzt sofern es sich bei beiden Ausdrücken um gültige Nummer handelt, folgende Formate werden unterstützt:
-  - Integer (Beispiele: 5, -7)
-  - Fließkommazahl (Beispiele: 5.2, -7.5, 2.83e-2)
-  - hexadezimale Zahl (Beispiele: 0xA3, -0xA3)
-Um einen Vergleich zwischen zwei Zeichenketten zu erzwingen, müssen die Ausdrücke in Anführungszeichen gesetzt werden, zum Beispiel:
+An expression is considered as "true" if it is not NULL, not empty, and different from "0".
+The comparison is made using floating point numbers if the two expressions are valid numbers, with one of the following formats:
+  - integer (examples: 5, -7)
+  - floating point number (examples: 5.2, -7.5, 2.83e-2)
+  - hexadecimal number (examples: 0xA3, -0xA3)
+To force a string comparison, you can add double quotes around each expression, for example:
  50 > 100      ==> 0
  "50" > "100"  ==> 1

-Einige Variablen werden im Ausdruck, mittels der Formatierung ${variable}, ersetzt. Mögliche Variablen sind, nach Reihenfolge ihrer Priorität:
-  1. eine evaluierte Teilzeichenkette (Format: "eval:xxx")
-  2. eine Zeichenkette mit Escapesequenzen (Format: "esc:xxx" oder "\xxx")
-  3. Zeichen welche in einer Zeichenkette nicht dargestellt werden sollen (Format: "hide:Zeichen,Zeichenkette")
-  4. eine Zeichenkette mit einer maximalen Anzahl an Zeichen (Format: "cut:+Max,Suffix,Zeichenkette")
-     oder maximale Anzahl an Zeichen die auf dem Bildschirm angezeigt werden sollen (Format: "cutscr:Max,Suffix,Zeichenkette oder "cutscr:+Max,Suffix,Zeichenkette")
-  5. Ende einer Zeichenkette nutzen (Format: "rev:xxx")
-  6. Wiederholung einer Zeichenkette  (Format: "repeat:Anzahl,Zeichenkette")
-  7. eine Farbe (Format: "color:xxx", siehe "Anleitung für API Erweiterung", Funktion "color")
-  8. eine Info (Format: "info:Name,Argumente", Argumente sind optional)
-  9. aktuelles Datum/Uhrzeit (Format: "date" oder "date:format")
-  10. eine Umgebungsvariable (Format: "env:XXX")
-  11. ein Dreifachoperand (Format: "if:Bedingung?Wert_falls_wahr:Wert_falls_unwahr")
-  12. eine Option (Format: "file.section.option")
-  13. der Name einer lokalen Variablen eines Buffer
-  14. ein hdata Name/Variable (der Wert wird automatisch in eine Zeichenkette konvertiert), standardmäßig wird für "window" und "buffer" das aktuelle Fenster/Buffer verwendet.
-Das Format für hdata kann wie folgt aufgebaut sein:
-  hdata.var1.var2...: startet mit hdata (der Pointer muss bekannt sein) und fragt eine Variable nach der anderen ab (weitere hdata können folgen)
-  hdata[list].var1.var2...: startet hdata mittels einer Liste, zum Beispiel:
-    ${buffer[gui_buffers].full_name}: der vollständige Name des ersten Buffers, in der verknüpften Liste aller Buffer
-    ${plugin[weechat_plugins].name}: Name der ersten Erweiterung, in der verknüpften Liste aller Erweiterungen
-  hdata[pointer].var1.var2...: startet hdata mittels einem Pointer, zum Beispiel:
-    ${buffer[0x1234abcd].full_name}: vollständiger Name eines Buffers und des dazugehörigen Pointers (kann in triggern benutzt werden)
-Die vorhandenen Namen für hdata und Variablen sind in der "Anleitung für API Erweiterung", Bereich "weechat_hdata_get". beschrieben
+Some variables are replaced in expression, using the format ${variable}, variable can be, by order of priority:
+  1. an evaluated sub-string (format: "eval:xxx")
+  2. a string with escaped chars (format: "esc:xxx" or "\xxx")
+  3. a string with chars to hide (format: "hide:char,string")
+  4. a string with max chars (format: "cut:max,suffix,string" or "cut:+max,suffix,string")
+     or max chars displayed on screen (format: "cutscr:max,suffix,string" or "cutscr:+max,suffix,string")
+  5. a reversed string (format: "rev:xxx")
+  6. a repeated string (format: "repeat:count,string")
+  7. a color (format: "color:xxx", see "Plugin API reference", function "color")
+  8. an info (format: "info:name,arguments", arguments are optional)
+  9. current date/time (format: "date" or "date:format")
+  10. an environment variable (format: "env:XXX")
+  11. a ternary operator (format: "if:condition?value_if_true:value_if_false")
+  12. result of an expression with parentheses and operators + - * / // % (format: "calc:xxx")
+  13. an option (format: "file.section.option")
+  14. a local variable in buffer
+  15. 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
+  hdata[pointer].var1.var2...: start with a hdata using a pointer, for example:
+    ${buffer[0x1234abcd].full_name}: full name of the buffer with this pointer (can be used in triggers)
+For name of hdata and variables, please look at "Plugin API reference", function "weechat_hdata_get".

-Beispiele (einfache Zeichenketten):
+Examples (simple strings):
  /eval -n ${info:version}                       ==> 0.4.3
  /eval -n ${env:HOME}                           ==> /home/user
  /eval -n ${weechat.look.scroll_amount}         ==> 3
-  /eval -n ${sec.data.freenode_password}         ==> geheim
+  /eval -n ${sec.data.freenode_password}         ==> secret
  /eval -n ${window}                             ==> 0x2549aa0
  /eval -n ${window.buffer}                      ==> 0x2549320
  /eval -n ${window.buffer.full_name}            ==> core.weechat
@@ -337,17 +338,18 @@ Beispiele (einfache Zeichenketten):
  /eval -n ${if:${info:term_width}>80?big:small} ==> big
  /eval -n ${rev:Hello}                          ==> olleH
  /eval -n ${repeat:5,-}                         ==> -----
+  /eval -n ${calc:(5+2)*3}                       ==> 21

-Beispiele (Bedingungen):
-  /eval -n -c ${window.buffer.number} > 2  ==> 0
-  /eval -n -c ${window.win_width} > 100    ==> 1
-  /eval -n -c (8 > 12) || (5 > 2)          ==> 1
-  /eval -n -c (8 > 12) && (5 > 2)          ==> 0
-  /eval -n -c abcd =~ ^ABC                 ==> 1
-  /eval -n -c abcd =~ (?-i)^ABC            ==> 0
-  /eval -n -c abcd =~ (?-i)^abc            ==> 1
-  /eval -n -c abcd !~ abc                  ==> 0
-  /eval -n -c abcd =* a*d                  ==> 1
+Examples (conditions):
+  /eval -n -c ${window.buffer.number} > 2 ==> 0
+  /eval -n -c ${window.win_width} > 100   ==> 1
+  /eval -n -c (8 > 12) || (5 > 2)         ==> 1
+  /eval -n -c (8 > 12) && (5 > 2)         ==> 0
+  /eval -n -c abcd =~ ^ABC                ==> 1
+  /eval -n -c abcd =~ (?-i)^ABC           ==> 0
+  /eval -n -c abcd =~ (?-i)^abc           ==> 1
+  /eval -n -c abcd !~ abc                 ==> 0
+  /eval -n -c abcd =* a*d                 ==> 1
 ----

 [[command_weechat_filter]]
@@ -308,9 +308,10 @@ Some variables are replaced in expression, using the format ${variable}, variabl
  9. current date/time (format: "date" or "date:format")
  10. an environment variable (format: "env:XXX")
  11. a ternary operator (format: "if:condition?value_if_true:value_if_false")
-  12. an option (format: "file.section.option")
-  13. a local variable in buffer
-  14. a hdata name/variable (the value is automatically converted to string), by default "window" and "buffer" point to current window/buffer.
+  12. result of an expression with parentheses and operators + - * / // % (format: "calc:xxx")
+  13. an option (format: "file.section.option")
+  14. a local variable in buffer
+  15. 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:
@@ -337,6 +338,7 @@ Examples (simple strings):
  /eval -n ${if:${info:term_width}>80?big:small} ==> big
  /eval -n ${rev:Hello}                          ==> olleH
  /eval -n ${repeat:5,-}                         ==> -----
+  /eval -n ${calc:(5+2)*3}                       ==> 21

 Examples (conditions):
  /eval -n -c ${window.buffer.number} > 2 ==> 0
@@ -120,6 +120,7 @@ WeeChat "core" is located in following directories:
 | core/                           | Core functions: entry point, internal structures.
 |    wee-arraylist.c              | Array lists.
 |    wee-backtrace.c              | Display a backtrace after a crash.
+|    wee-calc.c                   | Calculate result of expressions.
 |    wee-command.c                | WeeChat core commands.
 |    wee-completion.c             | Default completions.
 |    wee-config-file.c            | Configuration file management.
@@ -2148,7 +2148,7 @@ str3 = weechat.string_input_for_buffer("//test")  # "/test"

 ==== string_eval_expression

-_WeeChat ≥ 0.4.0, updated in 0.4.2, 0.4.3, 1.0, 1.1, 1.2, 1.3, 1.6, 1.8 and 2.0._
+_WeeChat ≥ 0.4.0, updated in 0.4.2, 0.4.3, 1.0, 1.1, 1.2, 1.3, 1.6, 1.8, 2.0 and 2.7._

 Evaluate an expression and return result as a string.
 Special variables with format `+${variable}+` are expanded (see table below).
@@ -2535,6 +2535,23 @@ expanded to last):
  `+${if:${info:term_width}>80?big:small}+` |
  `+big+`

+| `+${calc:xxx}+` +
+  (_WeeChat ≥ 2.7_) |
+  Result of expression, where parentheses and the following operators are
+  supported: +
+  `+`: addition +
+  `-`: subtraction +
+  `*`: multiplication +
+  `/`: division +
+  `//`: result of division without fractional part +
+  `%`: remainder of division. |
+  `+${calc:5+2*3}+` +
+  `+${calc:(5+2)*3}+` +
+  `+${calc:9.2%3}+` |
+  `+11+` +
+  `+21+` +
+  `+0.2+`
+
 | `+${sec.data.name}+` |
  Value of the secured data `name`. |
  `+${sec.data.freenode_pass}+` |
@@ -308,9 +308,10 @@ Des variables sont remplacées dans l'expression, en utilisant le format ${varia
  9. la date/heure courante (format : "date" ou "date:format")
  10. une variable d'environnement (format : "env:XXX")
  11. un opérateur ternaire (format : "if:condition?valeur_si_vrai:valeur_si_faux")
-  12. une option (format : "fichier.section.option")
-  13. une variable locale du tampon
-  14. un hdata/variable (la valeur est automatiquement convertie en chaîne), par défaut "window" et "buffer" pointent vers la fenêtre et le tampon courants.
+  12. le résultat d'une expression avec parenthèses et les opérateurs + - * / // % (format: "calc:xxx")
+  13. une option (format : "fichier.section.option")
+  14. une variable locale du tampon
+  15. 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[liste].var1.var2... : démarrer avec un hdata en utilisant une liste, par exemple :
@@ -337,6 +338,7 @@ Exemples (chaînes simples) :
  /eval -n ${if:${info:term_width}>80?big:small} ==> big
  /eval -n ${rev:Hello}                          ==> olleH
  /eval -n ${repeat:5,-}                         ==> -----
+  /eval -n ${calc:(5+2)*3}                       ==> 21

 Exemples (conditions) :
  /eval -n -c ${window.buffer.number} > 2 ==> 0
@@ -122,6 +122,7 @@ Le cœur de WeeChat est situé dans les répertoires suivants :
 | core/                           | Fonctions du cœur : point d'entrée, structures internes.
 |    wee-arraylist.c              | Listes avec tableau (« arraylists »).
 |    wee-backtrace.c              | Afficher une trace après un plantage.
+|    wee-calc.c                   | Calcul du résultat d'expressions.
 |    wee-command.c                | Commandes du cœur de WeeChat.
 |    wee-completion.c             | Complétions par défaut.
 |    wee-config-file.c            | Gestion des fichiers de configuration.
@@ -2188,7 +2188,7 @@ str3 = weechat.string_input_for_buffer("//test")  # "/test"

 ==== string_eval_expression

-_WeeChat ≥ 0.4.0, mis à jour dans la 0.4.2, 0.4.3, 1.0, 1.1, 1.2, 1.3, 1.6, 1.8 et 2.0._
+_WeeChat ≥ 0.4.0, mis à jour dans la 0.4.2, 0.4.3, 1.0, 1.1, 1.2, 1.3, 1.6, 1.8, 2.0 et 2.7._

 Évaluer l'expression et retourner le résultat sous forme de chaîne.
 Les variables spéciales avec le format `+${variable}+` sont étendues (voir le
@@ -2582,6 +2582,23 @@ première étendue à la dernière) :
  `+${if:${info:term_width}>80?grand:petit}+` |
  `+grand+`

+| `+${calc:xxx}+` +
+  (_WeeChat ≥ 2.7_) |
+  Résultat de l'expression, où les parenthèses et les opérateurs suivants sont
+  supportés : +
+  `+` : addition +
+  `-` : soustraction +
+  `*` : multiplication +
+  `/` : division +
+  `//` : résultat de la division sans la partie décimale +
+  `%` : reste de la division. |
+  `+${calc:5+2*3}+` +
+  `+${calc:(5+2)*3}+` +
+  `+${calc:9.2%3}+` |
+  `+11+` +
+  `+21+` +
+  `+0.2+`
+
 | `+${sec.data.nom}+` |
  Valeur de la donnée sécurisée `nom`. |
  `+${sec.data.freenode_pass}+` |
@@ -308,9 +308,10 @@ Some variables are replaced in expression, using the format ${variable}, variabl
  9. current date/time (format: "date" or "date:format")
  10. an environment variable (format: "env:XXX")
  11. a ternary operator (format: "if:condition?value_if_true:value_if_false")
-  12. an option (format: "file.section.option")
-  13. a local variable in buffer
-  14. a hdata name/variable (the value is automatically converted to string), by default "window" and "buffer" point to current window/buffer.
+  12. result of an expression with parentheses and operators + - * / // % (format: "calc:xxx")
+  13. an option (format: "file.section.option")
+  14. a local variable in buffer
+  15. 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:
@@ -337,6 +338,7 @@ Examples (simple strings):
  /eval -n ${if:${info:term_width}>80?big:small} ==> big
  /eval -n ${rev:Hello}                          ==> olleH
  /eval -n ${repeat:5,-}                         ==> -----
+  /eval -n ${calc:(5+2)*3}                       ==> 21

 Examples (conditions):
  /eval -n -c ${window.buffer.number} > 2 ==> 0
@@ -2242,7 +2242,7 @@ str3 = weechat.string_input_for_buffer("//test")  # "/test"
 ==== string_eval_expression

 // TRANSLATION MISSING
-_WeeChat ≥ 0.4.0, updated in 0.4.2, 0.4.3, 1.0, 1.1, 1.2, 1.3, 1.6, 1.8 and 2.0._
+_WeeChat ≥ 0.4.0, updated in 0.4.2, 0.4.3, 1.0, 1.1, 1.2, 1.3, 1.6, 1.8, 2.0 and 2.7._

 // TRANSLATION MISSING
 Evaluate an expression and return result as a string.
@@ -2642,6 +2642,24 @@ expanded to last):
  `+${if:${info:term_width}>80?big:small}+` |
  `+big+`

+// TRANSLATION MISSING
+| `+${calc:xxx}+` +
+  (_WeeChat ≥ 2.7_) |
+  Result of expression, where parentheses and the following operators are
+  supported: +
+  `+`: addition +
+  `-`: subtraction +
+  `*`: multiplication +
+  `/`: division +
+  `//`: result of division without fractional part +
+  `%`: remainder of division. |
+  `+${calc:5+2*3}+` +
+  `+${calc:(5+2)*3}+` +
+  `+${calc:9.2%3}+` |
+  `+11+` +
+  `+21+` +
+  `+0.2+`
+
 | `+${sec.data.name}+` |
  Value of the secured data `name`. |
  `+${sec.data.freenode_pass}+` |
@@ -266,61 +266,62 @@ infolists: インフォリストに関する情報を表示
 /eval  [-n|-s] <expression>
       [-n] -c <expression1> <operator> <expression2>

-        -n: 結果をバッファに送信せずに表示 (デバッグモード)
-        -s: 評価前に式を分割する (複数のコマンドを指定する場合はセミコロンで区切ってください)
-        -c: 条件として評価: 演算子と括弧をを使い、ブール値 ("0" または "1") を返します
-expression: 評価する式、${variable} 型の書式の変数は置換されます (以下を参照してください); 複数のコマンドを指定する場合はセミコロンで区切ってください
-  operator: 論理演算子や比較演算子:
-            - 論理演算子:
-                &&  ブール演算の "and"
-                ||  ブール演算の "or"
-            - 比較演算子:
-                ==  等しい
-                !=  等しくない
-                <=  以下
-                <   より少ない
-                >=  以上
-                >   より大きい
-                =~  POSIX 拡張正規表現にマッチ
-                !~  POSIX 拡張正規表現にマッチしない
-                =*  マスクにマッチ (ワイルドカード "*" を使えます)
-                !*  マスクにマッチしない (ワイルドカード "*" を使えます)
+        -n: display result without sending it to buffer (debug mode)
+        -s: split expression before evaluating it (many commands can be separated by semicolons)
+        -c: evaluate as condition: use operators and parentheses, return a boolean value ("0" or "1")
+expression: expression to evaluate, variables with format ${variable} are replaced (see below); many commands can be separated by semicolons
+  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 POSIX extended regex
+                !~  is NOT matching POSIX extended regex
+                =*  is matching mask (wildcard "*" is allowed)
+                !*  is NOT matching mask (wildcard "*" is allowed)

-式が NULL でない場合、空でない場合、"0" でない場合、式は "真" と評価されます。
-浮動小数点数として比較される数値表現の書式は以下です:
-  - 整数 (例: 5、-7)
-  - 浮動小数点数 (例: 5.2、-7.5、2.83e-2)
-  - 16 進数 (例: 0xA3、-0xA3)
-数値表現を二重引用符で括ることで、文字列として比較されます。例:
+An expression is considered as "true" if it is not NULL, not empty, and different from "0".
+The comparison is made using floating point numbers if the two expressions are valid numbers, with one of the following formats:
+  - integer (examples: 5, -7)
+  - floating point number (examples: 5.2, -7.5, 2.83e-2)
+  - hexadecimal number (examples: 0xA3, -0xA3)
+To force a string comparison, you can add double quotes around each expression, for example:
  50 > 100      ==> 0
  "50" > "100"  ==> 1

-式中の ${variable} 型の書式の変数は置換されます。変数は以下の優先順位に従います:
-  1. 評価済みのサブ文字列 (書式: "eval:xxx")
-  2. エスケープ文字を含む文字列 (書式: "esc:xxx" または "\xxx")
-  3. 隠す文字を含む文字列 (書式: "hide:char,string")
-  4. 最大文字数を指定した文字列 (書式: "cut:max,suffix,string" または "cut:+max,suffix,string")
-     または最大文字表示幅を指定した文字列 (書式: "cutscr:max,suffix,string" または "cutscr:+max,suffix,string")
-  5. 文字順を反転させた文字列 (書式: "rev:xxx")
-  6. 繰り返し文字列 (書式: "repeat:count,string")
-  7. 色 (書式: "color:xxx"、"プラグイン API リファレンス" の "color" 関数を参照してください)
-  8. 情報 (書式: "info:name,arguments"、arguments は任意)
-  9. 現在の日付/時刻 (書式: "date" または "date:format")
-  10. 環境変数 (書式: "env:XXX")
-  11. 三項演算子 (書式: "if:condition?value_if_true:value_if_false")
-  12. オプション (書式: "file.section.option")
-  13. バッファのローカル変数
-  14. hdata の名前/変数 (値は自動的に文字列に変換されます)、デフォルトでは "window" と "buffer" は現在のウィンドウ/バッファを指します。
-hdata の書式は以下の 1 つです:
-  hdata.var1.var2...: hdata (ポインタは既知) で開始し、1 個ずつ変数を続ける (他の hdata を続けることも可能)
-  hdata[list].var1.var2...: リストを使う hdata で開始する、例:
-    ${buffer[gui_buffers].full_name}: バッファリストにリンクされた最初のバッファのフルネーム
-    ${plugin[weechat_plugins].name}: プラグインリストにリンクされた最初のプラグインの名前
-  hdata[pointer].var1.var2...: ポインタを使う hdata で開始する、例:
-    ${buffer[0x1234abcd].full_name}: 与えたポインタを持つバッファの完全な名前 (トリガ中で使うことが可能です)
-hdata と変数の名前については、"プラグイン API リファレンス" の "weechat_hdata_get" 関数を参照してください。
+Some variables are replaced in expression, using the format ${variable}, variable can be, by order of priority:
+  1. an evaluated sub-string (format: "eval:xxx")
+  2. a string with escaped chars (format: "esc:xxx" or "\xxx")
+  3. a string with chars to hide (format: "hide:char,string")
+  4. a string with max chars (format: "cut:max,suffix,string" or "cut:+max,suffix,string")
+     or max chars displayed on screen (format: "cutscr:max,suffix,string" or "cutscr:+max,suffix,string")
+  5. a reversed string (format: "rev:xxx")
+  6. a repeated string (format: "repeat:count,string")
+  7. a color (format: "color:xxx", see "Plugin API reference", function "color")
+  8. an info (format: "info:name,arguments", arguments are optional)
+  9. current date/time (format: "date" or "date:format")
+  10. an environment variable (format: "env:XXX")
+  11. a ternary operator (format: "if:condition?value_if_true:value_if_false")
+  12. result of an expression with parentheses and operators + - * / // % (format: "calc:xxx")
+  13. an option (format: "file.section.option")
+  14. a local variable in buffer
+  15. 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
+  hdata[pointer].var1.var2...: start with a hdata using a pointer, for example:
+    ${buffer[0x1234abcd].full_name}: full name of the buffer with this pointer (can be used in triggers)
+For name of hdata and variables, please look at "Plugin API reference", function "weechat_hdata_get".

-例 (単純な文字列):
+Examples (simple strings):
  /eval -n ${info:version}                       ==> 0.4.3
  /eval -n ${env:HOME}                           ==> /home/user
  /eval -n ${weechat.look.scroll_amount}         ==> 3
@@ -335,10 +336,11 @@ hdata と変数の名前については、"プラグイン API リファレン
  /eval -n ${cut:+3,+,test}                      ==> te+
  /eval -n ${date:%H:%M:%S}                      ==> 07:46:40
  /eval -n ${if:${info:term_width}>80?big:small} ==> big
-  /eval -n ${rev:Hello}                          ==> olleH\n"
-  /eval -n ${repeat:5,-}                         ==> -----\n"
+  /eval -n ${rev:Hello}                          ==> olleH
+  /eval -n ${repeat:5,-}                         ==> -----
+  /eval -n ${calc:(5+2)*3}                       ==> 21

-例 (条件):
+Examples (conditions):
  /eval -n -c ${window.buffer.number} > 2 ==> 0
  /eval -n -c ${window.win_width} > 100   ==> 1
  /eval -n -c (8 > 12) || (5 > 2)         ==> 1
@@ -126,6 +126,8 @@ WeeChat "core" は以下のディレクトリに配置されています:
 | core/                           | コア関数: エントリポイント、内部構造体
 |    wee-arraylist.c              | 配列リスト
 |    wee-backtrace.c              | クラッシュした際にバックトレースを表示
+// TRANSLATION MISSING
+|    wee-calc.c                   | Calculate result of expressions.
 |    wee-command.c                | WeeChat コアコマンド
 |    wee-completion.c             | デフォルト補完
 |    wee-config-file.c            | 設定ファイル管理
@@ -2161,7 +2161,7 @@ str3 = weechat.string_input_for_buffer("//test")  # "/test"

 ==== string_eval_expression

-_WeeChat バージョン 0.4.0 以上で利用可、バージョン 0.4.2、0.4.3、1.0、1.1、1.2、1.3、1.6、1.8、2.0 で更新。_
+_WeeChat バージョン 0.4.0 以上で利用可、バージョン 0.4.2、0.4.3、1.0、1.1、1.2、1.3、1.6、1.8、2.0, 2.7 で更新。_

 式を評価して文字列として返す。`+${variable}+`
 という書式で書かれた特殊変数は展開されます (以下の表を参照)。
@@ -2546,6 +2546,24 @@ str5 = weechat.string_eval_expression("password=abc password=def", {}, {}, optio
  `+${if:${info:term_width}>80?big:small}+` |
  `+big+`

+// TRANSLATION MISSING
+| `+${calc:xxx}+` +
+  (_WeeChat バージョン 2.7 以上で利用可_) |
+  Result of expression, where parentheses and the following operators are
+  supported: +
+  `+`: addition +
+  `-`: subtraction +
+  `*`: multiplication +
+  `/`: division +
+  `//`: result of division without fractional part +
+  `%`: remainder of division. |
+  `+${calc:5+2*3}+` +
+  `+${calc:(5+2)*3}+` +
+  `+${calc:9.2%3}+` |
+  `+11+` +
+  `+21+` +
+  `+0.2+`
+
 | `+${sec.data.name}+` |
  セキュアデータ `name` の値 |
  `+${sec.data.freenode_pass}+` |
@@ -266,65 +266,66 @@ infolists: wyświetla informacje o infolistach
 /eval  [-n|-s] <wyrażenie>
       [-n] -c <wyrażenie1> <operator> <wyrażenie2>

-        -n: wyświetla wynik bez wysyłania go do buforu (tryb debugowania)
-        -s: podziel wyrażenie przed przetworzeniem go (wiele komend może być oddzielonych średnikami)
-        -c: przetwarza jako warunek: użyj operatorów i nawiasów, zwraca wartość logiczną ("0" lub "1")
-wyrażenie: wyrażenie do przetworzenia, zmienne o formacie ${zmienna} są zastępowane (zobacz niżej); wiele komend można oddzielić średnikami
-  operator: operator logiczny lub porównania:
-            - operatory logiczne:
-                &&  logiczne "i"
-                ||  logiczne "lub"
-            - operatory porównania:
-                ==  równy
-                !=  różny
-                <=  mniejszy lub równy
-                <   mniejszy
-                >=  większy lub równy
-                >   większy
-                =~  pasuje do rozszerzonego wyrażenia regularnego POSIX
-                !~  NIE pasuje do rozszerzonego wyrażenia regularnego POSIX
-                =*  pasuje do maski (dzika karta "*" dozwolona)
-                !*  NIE pasuje do maski (dzika karta "*" dozwolona)
+        -n: display result without sending it to buffer (debug mode)
+        -s: split expression before evaluating it (many commands can be separated by semicolons)
+        -c: evaluate as condition: use operators and parentheses, return a boolean value ("0" or "1")
+expression: expression to evaluate, variables with format ${variable} are replaced (see below); many commands can be separated by semicolons
+  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 POSIX extended regex
+                !~  is NOT matching POSIX extended regex
+                =*  is matching mask (wildcard "*" is allowed)
+                !*  is NOT matching mask (wildcard "*" is allowed)

-Wyrażenie jest uznawane za „prawdziwe” jeśli nie jest NULL, nie jest puste, oraz różni się od "0".
-Porównania dokonuje się z użyciem liczb całkowitych jeśli oba wyrażenia są liczbami całkowitymi, w jednym z następujących formatów:
-  - liczby całkowite (przykłady: 5, -7)
-  - liczby zmiennoprzecinkowe (przykłady: 5.2, -7.5, 2.83e-2)
-  - liczby szesnastkowe (przykłady: 0xA3, -0xA3)
-W celu wymuszenia porównywania ciągów, należy umieścić każde wyrażenie w cudzysłowie, na przykład:
+An expression is considered as "true" if it is not NULL, not empty, and different from "0".
+The comparison is made using floating point numbers if the two expressions are valid numbers, with one of the following formats:
+  - integer (examples: 5, -7)
+  - floating point number (examples: 5.2, -7.5, 2.83e-2)
+  - hexadecimal number (examples: 0xA3, -0xA3)
+To force a string comparison, you can add double quotes around each expression, for example:
  50 > 100      ==> 0
  "50" > "100"  ==> 1

-Niektóre zmienne w wyrażeniach są zamieniane, poprzez zastosowanie formatu ${zmienna}, według priorytetu zmienną może być:
-  1. przetworzony ciąg (format: "eval:xxx")
-  2. ciąg z wyescapowanymi znakami (format: "esc:xxx" lub "\xxx")
-  3. ciąg ze znakami do ukrycia (format: "hide:char,string")
-  4. ciąg o maksymalnej długości (format: "cut:max,suffix,string" lub "cut:+max,suffix,string")
-     lub maksymalna ilość znaków wyświetlanych na ekranie (format: "cutscr:max,suffix,string" lub "cutscr:+max,suffix,string")
-  5. odwrócony ciąg (format: "rev:xxx")
-  6. powtórzony ciąg (format: "repeat:ilość,ciąg")
-   7. kolor (format "color:xxx", zobacz „Opis API wtyczek”, funkcja "color")
-  8. informacja (format: "info:nazwa,argumenty", argumenty są opcjonalne)
-  9. obecna data/czas (format: "date" lub "date:format")
-  10. zmienna środowiskowa (format: "env:XXX")
-  11. wyrażenie warunkowe (format: "if:condition?value_if_true:value_if_false")
-  12. opcja (format: plik.sekcja.opcja)
-  13. zmienna lokalna w buforze
-  14. nazwa hdatay/zmiennej (wartość jest automatycznie konwertowana na ciąg znaków), domyślnie "window" i "buffer" wskazują na aktualne okno/bufor.
-Format dla hdata może być jednym z poniższych:
-  hdata.zmienna1.zmienna2...: inicjuje hdata (wskaźnik musi być znany), następnie wypytuje zmienne jedna po drugiej (inne hdata mogą być następne)
-  hdata[list].zmienna1.zmienna2...: inicjuje hdata z wykorzystaniem listy, na przykład:
-    ${buffer[gui_buffers].full_name}: pełna nazwa buforu w połączonej liście buforów
-    ${plugin[weechat_plugins].name}: nazwa pierwszej wtyczki w połączonej liście wtyczek
-  hdata[wskaźnik].zmienna1.zmienna2...: zacznij z hdata używając wskaźnika, na przykład:
-    ${buffer[0x1234abcd].full_name}: pełna nazwa buforu z tym wskaźnikiem (może zostać użyte w triggerach)
-Nazwy hdata i zmiennych, można znaleźć w  „Opisie API wtyczek”, funkcja "weechat_hdata_get".
+Some variables are replaced in expression, using the format ${variable}, variable can be, by order of priority:
+  1. an evaluated sub-string (format: "eval:xxx")
+  2. a string with escaped chars (format: "esc:xxx" or "\xxx")
+  3. a string with chars to hide (format: "hide:char,string")
+  4. a string with max chars (format: "cut:max,suffix,string" or "cut:+max,suffix,string")
+     or max chars displayed on screen (format: "cutscr:max,suffix,string" or "cutscr:+max,suffix,string")
+  5. a reversed string (format: "rev:xxx")
+  6. a repeated string (format: "repeat:count,string")
+  7. a color (format: "color:xxx", see "Plugin API reference", function "color")
+  8. an info (format: "info:name,arguments", arguments are optional)
+  9. current date/time (format: "date" or "date:format")
+  10. an environment variable (format: "env:XXX")
+  11. a ternary operator (format: "if:condition?value_if_true:value_if_false")
+  12. result of an expression with parentheses and operators + - * / // % (format: "calc:xxx")
+  13. an option (format: "file.section.option")
+  14. a local variable in buffer
+  15. 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
+  hdata[pointer].var1.var2...: start with a hdata using a pointer, for example:
+    ${buffer[0x1234abcd].full_name}: full name of the buffer with this pointer (can be used in triggers)
+For name of hdata and variables, please look at "Plugin API reference", function "weechat_hdata_get".

-Przykłady (proste ciągi):
+Examples (simple strings):
  /eval -n ${info:version}                       ==> 0.4.3
  /eval -n ${env:HOME}                           ==> /home/user
  /eval -n ${weechat.look.scroll_amount}         ==> 3
-  /eval -n ${sec.data.freenode_password}        ==> secret
+  /eval -n ${sec.data.freenode_password}         ==> secret
  /eval -n ${window}                             ==> 0x2549aa0
  /eval -n ${window.buffer}                      ==> 0x2549320
  /eval -n ${window.buffer.full_name}            ==> core.weechat
@@ -337,8 +338,9 @@ Przykłady (proste ciągi):
  /eval -n ${if:${info:term_width}>80?big:small} ==> big
  /eval -n ${rev:Hello}                          ==> olleH
  /eval -n ${repeat:5,-}                         ==> -----
+  /eval -n ${calc:(5+2)*3}                       ==> 21

-Przykłady (warunki):
+Examples (conditions):
  /eval -n -c ${window.buffer.number} > 2 ==> 0
  /eval -n -c ${window.win_width} > 100   ==> 1
  /eval -n -c (8 > 12) || (5 > 2)         ==> 1
@@ -41,6 +41,8 @@
 ./src/core/wee-backtrace.h
 ./src/core/weechat.c
 ./src/core/weechat.h
+./src/core/wee-calc.c
+./src/core/wee-calc.h
 ./src/core/wee-command.c
 ./src/core/wee-command.h
 ./src/core/wee-completion.c
@@ -21,7 +21,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2019-09-19 21:16+0200\n"
+"POT-Creation-Date: 2019-09-20 21:31+0200\n"
 "PO-Revision-Date: 2019-05-13 21:31+0200\n"
 "Last-Translator: Ondřej Súkup <mimi.vx@gmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -1579,9 +1579,11 @@ msgid ""
 "  10. an environment variable (format: \"env:XXX\")\n"
 "  11. a ternary operator (format: \"if:condition?value_if_true:value_if_false"
 "\")\n"
-"  12. an option (format: \"file.section.option\")\n"
-"  13. a local variable in buffer\n"
-"  14. a hdata name/variable (the value is automatically converted to "
+"  12. result of an expression with parentheses and operators + - * / // % "
+"(format: \"calc:xxx\")\n"
+"  13. an option (format: \"file.section.option\")\n"
+"  14. a local variable in buffer\n"
+"  15. 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"
@@ -1616,6 +1618,7 @@ msgid ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Examples (conditions):\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -24,7 +24,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2019-09-19 21:16+0200\n"
+"POT-Creation-Date: 2019-09-20 21:31+0200\n"
 "PO-Revision-Date: 2019-09-19 21:52+0200\n"
 "Last-Translator: Nils Görs <weechatter@arcor.de>\n"
 "Language-Team: German <kde-i18n-de@kde.org>\n"
@@ -1661,6 +1661,7 @@ msgstr "evaluierter Ausdruck"
 msgid "[-n|-s] <expression> || [-n] -c <expression1> <operator> <expression2>"
 msgstr "[-n|-s] <expression> || [-n] -c <expression1> <operator> <expression2>"

+#, fuzzy
 msgid ""
 "        -n: display result without sending it to buffer (debug mode)\n"
 "        -s: split expression before evaluating it (many commands can be "
@@ -1715,9 +1716,11 @@ msgid ""
 "  10. an environment variable (format: \"env:XXX\")\n"
 "  11. a ternary operator (format: \"if:condition?value_if_true:value_if_false"
 "\")\n"
-"  12. an option (format: \"file.section.option\")\n"
-"  13. a local variable in buffer\n"
-"  14. a hdata name/variable (the value is automatically converted to "
+"  12. result of an expression with parentheses and operators + - * / // % "
+"(format: \"calc:xxx\")\n"
+"  13. an option (format: \"file.section.option\")\n"
+"  14. a local variable in buffer\n"
+"  15. 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"
@@ -1752,6 +1755,7 @@ msgid ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Examples (conditions):\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -22,7 +22,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2019-09-19 21:16+0200\n"
+"POT-Creation-Date: 2019-09-20 21:31+0200\n"
 "PO-Revision-Date: 2019-05-13 21:31+0200\n"
 "Last-Translator: Elián Hanisch <lambdae2@gmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -1610,9 +1610,11 @@ msgid ""
 "  10. an environment variable (format: \"env:XXX\")\n"
 "  11. a ternary operator (format: \"if:condition?value_if_true:value_if_false"
 "\")\n"
-"  12. an option (format: \"file.section.option\")\n"
-"  13. a local variable in buffer\n"
-"  14. a hdata name/variable (the value is automatically converted to "
+"  12. result of an expression with parentheses and operators + - * / // % "
+"(format: \"calc:xxx\")\n"
+"  13. an option (format: \"file.section.option\")\n"
+"  14. a local variable in buffer\n"
+"  15. 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"
@@ -1647,6 +1649,7 @@ msgid ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Examples (conditions):\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -21,8 +21,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2019-09-19 21:16+0200\n"
-"PO-Revision-Date: 2019-09-19 21:18+0200\n"
+"POT-Creation-Date: 2019-09-20 21:31+0200\n"
+"PO-Revision-Date: 2019-09-20 21:32+0200\n"
 "Last-Translator: Sébastien Helleu <flashcode@flashtux.org>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
 "Language: fr\n"
@@ -1684,9 +1684,11 @@ msgid ""
 "  10. an environment variable (format: \"env:XXX\")\n"
 "  11. a ternary operator (format: \"if:condition?value_if_true:value_if_false"
 "\")\n"
-"  12. an option (format: \"file.section.option\")\n"
-"  13. a local variable in buffer\n"
-"  14. a hdata name/variable (the value is automatically converted to "
+"  12. result of an expression with parentheses and operators + - * / // % "
+"(format: \"calc:xxx\")\n"
+"  13. an option (format: \"file.section.option\")\n"
+"  14. a local variable in buffer\n"
+"  15. 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"
@@ -1721,6 +1723,7 @@ msgid ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Examples (conditions):\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -1793,9 +1796,11 @@ msgstr ""
 "  10. une variable d'environnement (format : \"env:XXX\")\n"
 "  11. un opérateur ternaire (format : \"if:condition?valeur_si_vrai:"
 "valeur_si_faux\")\n"
-"  12. une option (format : \"fichier.section.option\")\n"
-"  13. une variable locale du tampon\n"
-"  14. un hdata/variable (la valeur est automatiquement convertie en chaîne), "
+"  12. le résultat d'une expression avec parenthèses et les opérateurs + - "
+"* / // % (format: \"calc:xxx\")\n"
+"  13. une option (format : \"fichier.section.option\")\n"
+"  14. une variable locale du tampon\n"
+"  15. 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"
@@ -1832,6 +1837,7 @@ msgstr ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Exemples (conditions) :\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -20,7 +20,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2019-09-19 21:16+0200\n"
+"POT-Creation-Date: 2019-09-20 21:31+0200\n"
 "PO-Revision-Date: 2019-05-13 21:31+0200\n"
 "Last-Translator: Andras Voroskoi <voroskoi@frugalware.org>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -1498,9 +1498,11 @@ msgid ""
 "  10. an environment variable (format: \"env:XXX\")\n"
 "  11. a ternary operator (format: \"if:condition?value_if_true:value_if_false"
 "\")\n"
-"  12. an option (format: \"file.section.option\")\n"
-"  13. a local variable in buffer\n"
-"  14. a hdata name/variable (the value is automatically converted to "
+"  12. result of an expression with parentheses and operators + - * / // % "
+"(format: \"calc:xxx\")\n"
+"  13. an option (format: \"file.section.option\")\n"
+"  14. a local variable in buffer\n"
+"  15. 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"
@@ -1535,6 +1537,7 @@ msgid ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Examples (conditions):\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -20,7 +20,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2019-09-19 21:16+0200\n"
+"POT-Creation-Date: 2019-09-20 21:31+0200\n"
 "PO-Revision-Date: 2019-05-13 21:31+0200\n"
 "Last-Translator: Esteban I. Ruiz Moreno <exio4.com@gmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -1593,9 +1593,11 @@ msgid ""
 "  10. an environment variable (format: \"env:XXX\")\n"
 "  11. a ternary operator (format: \"if:condition?value_if_true:value_if_false"
 "\")\n"
-"  12. an option (format: \"file.section.option\")\n"
-"  13. a local variable in buffer\n"
-"  14. a hdata name/variable (the value is automatically converted to "
+"  12. result of an expression with parentheses and operators + - * / // % "
+"(format: \"calc:xxx\")\n"
+"  13. an option (format: \"file.section.option\")\n"
+"  14. a local variable in buffer\n"
+"  15. 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"
@@ -1630,6 +1632,7 @@ msgid ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Examples (conditions):\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -20,7 +20,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2019-09-19 21:16+0200\n"
+"POT-Creation-Date: 2019-09-20 21:31+0200\n"
 "PO-Revision-Date: 2019-06-22 08:40+0200\n"
 "Last-Translator: AYANOKOUZI, Ryuunosuke <i38w7i3@yahoo.co.jp>\n"
 "Language-Team: Japanese <https://github.com/l/weechat/tree/master/"
@@ -1592,6 +1592,7 @@ msgstr "式を評価"
 msgid "[-n|-s] <expression> || [-n] -c <expression1> <operator> <expression2>"
 msgstr "[-n|-s] <expression> || [-n] -c <expression1> <operator> <expression2>"

+#, fuzzy
 msgid ""
 "        -n: display result without sending it to buffer (debug mode)\n"
 "        -s: split expression before evaluating it (many commands can be "
@@ -1646,9 +1647,11 @@ msgid ""
 "  10. an environment variable (format: \"env:XXX\")\n"
 "  11. a ternary operator (format: \"if:condition?value_if_true:value_if_false"
 "\")\n"
-"  12. an option (format: \"file.section.option\")\n"
-"  13. a local variable in buffer\n"
-"  14. a hdata name/variable (the value is automatically converted to "
+"  12. result of an expression with parentheses and operators + - * / // % "
+"(format: \"calc:xxx\")\n"
+"  13. an option (format: \"file.section.option\")\n"
+"  14. a local variable in buffer\n"
+"  15. 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"
@@ -1683,6 +1686,7 @@ msgid ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Examples (conditions):\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -22,7 +22,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2019-09-19 21:16+0200\n"
+"POT-Creation-Date: 2019-09-20 21:31+0200\n"
 "PO-Revision-Date: 2019-09-07 15:45+0200\n"
 "Last-Translator: Krzysztof Korościk <soltys@soltys.info>\n"
 "Language-Team: Polish <kde-i18n-doc@kde.org>\n"
@@ -1627,6 +1627,7 @@ msgstr "przetwórz wyrażenie"
 msgid "[-n|-s] <expression> || [-n] -c <expression1> <operator> <expression2>"
 msgstr "[-n|-s] <wyrażenie> || [-n] -c <wyrażenie1> <operator> <wyrażenie2>"

+#, fuzzy
 msgid ""
 "        -n: display result without sending it to buffer (debug mode)\n"
 "        -s: split expression before evaluating it (many commands can be "
@@ -1681,9 +1682,11 @@ msgid ""
 "  10. an environment variable (format: \"env:XXX\")\n"
 "  11. a ternary operator (format: \"if:condition?value_if_true:value_if_false"
 "\")\n"
-"  12. an option (format: \"file.section.option\")\n"
-"  13. a local variable in buffer\n"
-"  14. a hdata name/variable (the value is automatically converted to "
+"  12. result of an expression with parentheses and operators + - * / // % "
+"(format: \"calc:xxx\")\n"
+"  13. an option (format: \"file.section.option\")\n"
+"  14. a local variable in buffer\n"
+"  15. 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"
@@ -1718,6 +1721,7 @@ msgid ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Examples (conditions):\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -20,7 +20,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2019-09-19 21:16+0200\n"
+"POT-Creation-Date: 2019-09-20 21:31+0200\n"
 "PO-Revision-Date: 2019-05-13 21:32+0200\n"
 "Last-Translator: Vasco Almeida <vascomalmeida@sapo.pt>\n"
 "Language-Team: Portuguese <>\n"
@@ -1651,9 +1651,11 @@ msgid ""
 "  10. an environment variable (format: \"env:XXX\")\n"
 "  11. a ternary operator (format: \"if:condition?value_if_true:value_if_false"
 "\")\n"
-"  12. an option (format: \"file.section.option\")\n"
-"  13. a local variable in buffer\n"
-"  14. a hdata name/variable (the value is automatically converted to "
+"  12. result of an expression with parentheses and operators + - * / // % "
+"(format: \"calc:xxx\")\n"
+"  13. an option (format: \"file.section.option\")\n"
+"  14. a local variable in buffer\n"
+"  15. 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"
@@ -1688,6 +1690,7 @@ msgid ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Examples (conditions):\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -21,7 +21,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2019-09-19 21:16+0200\n"
+"POT-Creation-Date: 2019-09-20 21:31+0200\n"
 "PO-Revision-Date: 2019-05-13 21:32+0200\n"
 "Last-Translator: Eduardo Elias <camponez@gmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -1655,9 +1655,11 @@ msgid ""
 "  10. an environment variable (format: \"env:XXX\")\n"
 "  11. a ternary operator (format: \"if:condition?value_if_true:value_if_false"
 "\")\n"
-"  12. an option (format: \"file.section.option\")\n"
-"  13. a local variable in buffer\n"
-"  14. a hdata name/variable (the value is automatically converted to "
+"  12. result of an expression with parentheses and operators + - * / // % "
+"(format: \"calc:xxx\")\n"
+"  13. an option (format: \"file.section.option\")\n"
+"  14. a local variable in buffer\n"
+"  15. 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"
@@ -1692,6 +1694,7 @@ msgid ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Examples (conditions):\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -21,7 +21,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2019-09-19 21:16+0200\n"
+"POT-Creation-Date: 2019-09-20 21:31+0200\n"
 "PO-Revision-Date: 2019-05-13 21:32+0200\n"
 "Last-Translator: Aleksey V Zapparov AKA ixti <ixti@member.fsf.org>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -1520,9 +1520,11 @@ msgid ""
 "  10. an environment variable (format: \"env:XXX\")\n"
 "  11. a ternary operator (format: \"if:condition?value_if_true:value_if_false"
 "\")\n"
-"  12. an option (format: \"file.section.option\")\n"
-"  13. a local variable in buffer\n"
-"  14. a hdata name/variable (the value is automatically converted to "
+"  12. result of an expression with parentheses and operators + - * / // % "
+"(format: \"calc:xxx\")\n"
+"  13. an option (format: \"file.section.option\")\n"
+"  14. a local variable in buffer\n"
+"  15. 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"
@@ -1557,6 +1559,7 @@ msgid ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Examples (conditions):\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -42,6 +42,8 @@ SET(WEECHAT_SOURCES
 ./src/core/wee-backtrace.h
 ./src/core/weechat.c
 ./src/core/weechat.h
+./src/core/wee-calc.c
+./src/core/wee-calc.h
 ./src/core/wee-command.c
 ./src/core/wee-command.h
 ./src/core/wee-completion.c
@@ -20,7 +20,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2019-09-19 21:16+0200\n"
+"POT-Creation-Date: 2019-09-20 21:31+0200\n"
 "PO-Revision-Date: 2019-05-13 21:32+0200\n"
 "Last-Translator: Hasan Kiran <sunder67@hotmail.com>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -1351,9 +1351,11 @@ msgid ""
 "  10. an environment variable (format: \"env:XXX\")\n"
 "  11. a ternary operator (format: \"if:condition?value_if_true:value_if_false"
 "\")\n"
-"  12. an option (format: \"file.section.option\")\n"
-"  13. a local variable in buffer\n"
-"  14. a hdata name/variable (the value is automatically converted to "
+"  12. result of an expression with parentheses and operators + - * / // % "
+"(format: \"calc:xxx\")\n"
+"  13. an option (format: \"file.section.option\")\n"
+"  14. a local variable in buffer\n"
+"  15. 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"
@@ -1388,6 +1390,7 @@ msgid ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Examples (conditions):\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -21,7 +21,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: WeeChat\n"
 "Report-Msgid-Bugs-To: flashcode@flashtux.org\n"
-"POT-Creation-Date: 2019-09-19 21:16+0200\n"
+"POT-Creation-Date: 2019-09-20 21:31+0200\n"
 "PO-Revision-Date: 2014-08-16 10:27+0200\n"
 "Last-Translator: Sébastien Helleu <flashcode@flashtux.org>\n"
 "Language-Team: weechat-dev <weechat-dev@nongnu.org>\n"
@@ -1353,9 +1353,11 @@ msgid ""
 "  10. an environment variable (format: \"env:XXX\")\n"
 "  11. a ternary operator (format: \"if:condition?value_if_true:value_if_false"
 "\")\n"
-"  12. an option (format: \"file.section.option\")\n"
-"  13. a local variable in buffer\n"
-"  14. a hdata name/variable (the value is automatically converted to "
+"  12. result of an expression with parentheses and operators + - * / // % "
+"(format: \"calc:xxx\")\n"
+"  13. an option (format: \"file.section.option\")\n"
+"  14. a local variable in buffer\n"
+"  15. 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"
@@ -1390,6 +1392,7 @@ msgid ""
 "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
 "  /eval -n ${rev:Hello}                          ==> olleH\n"
 "  /eval -n ${repeat:5,-}                         ==> -----\n"
+"  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
 "\n"
 "Examples (conditions):\n"
 "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -23,6 +23,7 @@ set(LIB_CORE_SRC
  weechat.c weechat.h
  wee-arraylist.c wee-arraylist.h
  wee-backtrace.c wee-backtrace.h
+  wee-calc.c wee-calc.h
  wee-command.c wee-command.h
  wee-completion.c wee-completion.h
  wee-config.c wee-config.h
@@ -27,6 +27,8 @@ lib_weechat_core_a_SOURCES = weechat.c \
                             wee-arraylist.h \
                             wee-backtrace.c \
                             wee-backtrace.h \
+                             wee-calc.c \
+                             wee-calc.h \
                             wee-command.c \
                             wee-command.h \
                             wee-completion.c \
@@ -0,0 +1,355 @@
+/*
+ * wee-calc.c - calculate result of an expression
+ *
+ * Copyright (C) 2019 Sébastien 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 <https://www.gnu.org/licenses/>.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <math.h>
+#include <locale.h>
+
+#include "weechat.h"
+#include "wee-arraylist.h"
+#include "wee-string.h"
+
+
+/*
+ * Callback called to free a value or op in the arraylist.
+ */
+
+void
+calc_list_free_cb (void *data, struct t_arraylist *arraylist, void *pointer)
+{
+    /* make C compiler happy */
+    (void) data;
+    (void) arraylist;
+
+    free (pointer);
+}
+
+/*
+ * Returns the precedence of an operator:
+ *   - '*' and '/': 2
+ *   - '+' and '-': 1
+ *   - any other: 0
+ */
+
+int
+calc_operator_precedence (char *operator)
+{
+    if (!operator)
+        return 0;
+
+    if ((strcmp (operator, "*") == 0)
+        || (strcmp (operator, "/") == 0)
+        || (strcmp (operator, "//") == 0)
+        || (strcmp (operator, "%") == 0))
+    {
+        return 2;
+    }
+
+    if ((strcmp (operator, "+") == 0)
+        || (strcmp (operator, "-") == 0))
+    {
+        return 1;
+    }
+
+    return 0;
+}
+
+/*
+ * Pops an integer value from the stack of values.
+ */
+
+double
+calc_pop_value (struct t_arraylist *list_values)
+{
+    int size_values;
+    double *ptr_value, value;
+
+    size_values = arraylist_size (list_values);
+
+    if (size_values < 1)
+        return 0;
+
+    ptr_value = arraylist_get (list_values, size_values - 1);
+    value = *ptr_value;
+
+    arraylist_remove (list_values, size_values - 1);
+
+    return value;
+}
+
+/*
+ * Calculates result of an operation using an operator and two values.
+ */
+
+double
+calc_operation (char *operator, double value1, double value2)
+{
+    if (strcmp (operator, "+") == 0)
+        return value1 + value2;
+
+    if (strcmp (operator, "-") == 0)
+        return value1 - value2;
+
+    if (strcmp (operator, "*") == 0)
+        return value1 * value2;
+
+    if (strcmp (operator, "/") == 0)
+        return (value2 != 0) ? value1 / value2 : 0;
+
+    if (strcmp (operator, "//") == 0)
+        return (value2 != 0) ? floor (value1 / value2) : 0;
+
+    if (strcmp (operator, "%") == 0)
+        return (value2 != 0) ? fmod (value1, value2) : 0;
+
+    return 0;
+}
+
+/*
+ * Calculates result of an operation using the operator on the operators stack
+ * and the two values on the values stack.
+ *
+ * The result is pushed on values stack.
+ */
+
+void
+calc_operation_stacks (struct t_arraylist *list_values,
+                       struct t_arraylist *list_ops)
+{
+    int size_ops;
+    double value1, value2, result, *ptr_result;
+    char *ptr_operator;
+
+    size_ops = arraylist_size (list_ops);
+    if (size_ops < 1)
+        return;
+
+    ptr_operator = arraylist_get (list_ops, size_ops - 1);
+
+    value2 = calc_pop_value (list_values);
+    value1 = calc_pop_value (list_values);
+
+    result = calc_operation (ptr_operator, value1, value2);
+
+    ptr_result = malloc (sizeof (result));
+    *ptr_result = result;
+    arraylist_add (list_values, ptr_result);
+
+    arraylist_remove (list_ops, size_ops - 1);
+}
+
+/*
+ * Formats the result as a decimal number (locale independent): remove any
+ * extra "0" at the and the decimal point if needed.
+ */
+
+void
+calc_format_result (double value, char *result, int max_size)
+{
+    char *pos_point;
+    int i;
+
+    /*
+     * local-independent formatting of value, so that a decimal point is always
+     * used (instead of a comma in French for example)
+     */
+    setlocale (LC_ALL, "C");
+    snprintf (result, max_size, "%.10f", value);
+    setlocale (LC_ALL, "");
+
+    pos_point = strchr (result, '.');
+
+    i = strlen (result) - 1;
+    while (i >= 0)
+    {
+        if (!isdigit (result[i]) && (result[i] != '-'))
+        {
+            result[i] = '\0';
+            break;
+        }
+        if (pos_point && (result[i] == '0'))
+        {
+            result[i] = '\0';
+            i--;
+        }
+        else
+            break;
+    }
+}
+
+/*
+ * Calculates an expression, which can contain:
+ *   - integer and decimal numbers (ie 2 or 2.5)
+ *   - operators:
+ *       +: addition
+ *       -: subtraction
+ *       *: multiplication
+ *       /: division
+ *       \: division giving an integer as result
+ *       %: remainder of division
+ *   - parentheses: ( )
+ *
+ * The value returned is a string representation of the result, which can be
+ * an integer or a double, according to the operations and numbers in input.
+ *
+ * Note: result must be freed after use (if not NULL).
+ */
+
+char *
+calc_expression (const char *expr)
+{
+    struct t_arraylist *list_values, *list_ops;
+    char str_result[64], *ptr_operator, *operator;
+    int i, i2, index_op, decimals;
+    double value, *ptr_value;
+
+    list_values = NULL;
+    list_ops = NULL;
+
+    /* return 0 by default in case of error */
+    snprintf (str_result, sizeof (str_result), "0");
+
+    if (!expr)
+        goto end;
+
+    /* stack with values */
+    list_values = arraylist_new (32, 0, 1,
+                                 NULL, NULL,
+                                 &calc_list_free_cb, NULL);
+    if (!list_values)
+        goto end;
+
+    /* stack with operators */
+    list_ops = arraylist_new (32, 0, 1,
+                              NULL, NULL,
+                              &calc_list_free_cb, NULL);
+    if (!list_ops)
+        goto end;
+
+    for (i = 0; expr[i]; i++)
+    {
+        if (expr[i] == ' ')
+        {
+            /* ignore spaces */
+            continue;
+        }
+        else if (expr[i] == '(')
+        {
+            ptr_operator = string_strndup (expr + i, 1);
+            arraylist_add (list_ops, ptr_operator);
+        }
+        else if (isdigit (expr[i]) || (expr[i] == '.'))
+        {
+            value = 0;
+            decimals = 0;
+            while (expr[i] && (isdigit (expr[i]) || (expr[i] == '.')))
+            {
+                if (expr[i] == '.')
+                {
+                    if (decimals == 0)
+                        decimals = 10;
+                }
+                else
+                {
+                    if (decimals)
+                    {
+                        value = value + (((double)(expr[i] - '0')) / decimals);
+                        decimals *= 10;
+                    }
+                    else
+                    {
+                        value = (value * 10) + (expr[i] - '0');
+                    }
+                }
+                i++;
+            }
+            i--;
+            ptr_value = malloc (sizeof (value));
+            *ptr_value = value;
+            arraylist_add (list_values, ptr_value);
+        }
+        else if (expr[i] == ')')
+        {
+            index_op = arraylist_size (list_ops) - 1;
+            while (index_op >= 0)
+            {
+                ptr_operator = arraylist_get (list_ops, index_op);
+                if (strcmp (ptr_operator, "(") == 0)
+                    break;
+                calc_operation_stacks (list_values, list_ops);
+                index_op--;
+            }
+            /* remove "(" from operators */
+            index_op = arraylist_size (list_ops) - 1;
+            if (index_op >= 0)
+                arraylist_remove (list_ops, index_op);
+        }
+        else
+        {
+            /* operator */
+            i2 = i + 1;
+            while (expr[i2] && (expr[i2] != ' ') && (expr[i2] != '(')
+                   && (expr[i2] != ')') && (expr[i2] != '.')
+                   && !isdigit (expr[i2]))
+            {
+                i2++;
+            }
+            operator = string_strndup (expr + i, i2 - i);
+            i = i2 - 1;
+            if (operator)
+            {
+                index_op = arraylist_size (list_ops) - 1;
+                while (index_op >= 0)
+                {
+                    ptr_operator = arraylist_get (list_ops, index_op);
+                    if (calc_operator_precedence (ptr_operator) <
+                        calc_operator_precedence (operator))
+                        break;
+                    calc_operation_stacks (list_values, list_ops);
+                    index_op--;
+                }
+                arraylist_add (list_ops, operator);
+            }
+        }
+    }
+
+    while (arraylist_size (list_ops) > 0)
+    {
+        calc_operation_stacks (list_values, list_ops);
+    }
+
+    value = calc_pop_value (list_values);
+    calc_format_result (value, str_result, sizeof (str_result));
+
+end:
+    if (list_values)
+        arraylist_free (list_values);
+    if (list_ops)
+        arraylist_free (list_ops);
+
+    return strdup (str_result);
+}
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2019 Sébastien 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 <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef WEECHAT_CALC_H
+#define WEECHAT_CALC_H
+
+extern char *calc_expression (const char *expr);
+
+#endif /* WEECHAT_CALC_H */
@@ -7363,9 +7363,11 @@ command_init ()
           "  10. an environment variable (format: \"env:XXX\")\n"
           "  11. a ternary operator (format: "
           "\"if:condition?value_if_true:value_if_false\")\n"
-           "  12. an option (format: \"file.section.option\")\n"
-           "  13. a local variable in buffer\n"
-           "  14. a hdata name/variable (the value is automatically converted "
+           "  12. result of an expression with parentheses and operators "
+           "+ - * / // % (format: \"calc:xxx\")\n"
+           "  13. an option (format: \"file.section.option\")\n"
+           "  14. a local variable in buffer\n"
+           "  15. 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"
@@ -7401,6 +7403,7 @@ command_init ()
           "  /eval -n ${if:${info:term_width}>80?big:small} ==> big\n"
           "  /eval -n ${rev:Hello}                          ==> olleH\n"
           "  /eval -n ${repeat:5,-}                         ==> -----\n"
+           "  /eval -n ${calc:(5+2)*3}                       ==> 21\n"
           "\n"
           "Examples (conditions):\n"
           "  /eval -n -c ${window.buffer.number} > 2 ==> 0\n"
@@ -30,6 +30,7 @@

 #include "weechat.h"
 #include "wee-eval.h"
+#include "wee-calc.h"
 #include "wee-config-file.h"
 #include "wee-hashtable.h"
 #include "wee-hdata.h"
@@ -301,9 +302,10 @@ end:
 *  11. current date/time (format: date or date:xxx)
 *  12. an environment variable (format: env:XXX)
 *  13. a ternary operator (format: if:condition?value_if_true:value_if_false)
- *  14. an option (format: file.section.option)
- *  15. a buffer local variable
- *  16. a hdata variable (format: hdata.var1.var2 or hdata[list].var1.var2
+ *  14. calculate result of an expression (format: calc:xxx)
+ *  15. an option (format: file.section.option)
+ *  16. a buffer local variable
+ *  17. a hdata variable (format: hdata.var1.var2 or hdata[list].var1.var2
 *                        or hdata[ptr].var1.var2)
 *
 * See /help in WeeChat for examples.
@@ -625,7 +627,16 @@ eval_replace_vars_cb (void *data, const char *text)
        return (value) ? value : strdup ("");
    }

-    /* 14. option: if found, return this value */
+    /*
+     * 14. calculate the result of an expression
+     * (with number, operators and parentheses)
+     */
+    if (strncmp (text, "calc:", 5) == 0)
+    {
+        return calc_expression (text + 5);
+    }
+
+    /* 15. option: if found, return this value */
    if (strncmp (text, "sec.data.", 9) == 0)
    {
        ptr_value = hashtable_get (secure_hashtable_data, text + 9);
@@ -658,7 +669,7 @@ eval_replace_vars_cb (void *data, const char *text)
        }
    }

-    /* 15. local variable in buffer */
+    /* 16. local variable in buffer */
    ptr_buffer = hashtable_get (eval_context->pointers, "buffer");
    if (ptr_buffer)
    {
@@ -667,7 +678,7 @@ eval_replace_vars_cb (void *data, const char *text)
            return strdup (ptr_value);
    }

-    /* 16. hdata */
+    /* 17. hdata */
    value = NULL;
    hdata_name = NULL;
    list_name = NULL;
@@ -26,6 +26,7 @@ include_directories(${CPPUTEST_INCLUDE_DIRS} ${PROJECT_BINARY_DIR} ${PROJECT_SOU
 set(LIB_WEECHAT_UNIT_TESTS_CORE_SRC
  unit/test-plugins.cpp
  unit/core/test-core-arraylist.cpp
+  unit/core/test-core-calc.cpp
  unit/core/test-core-eval.cpp
  unit/core/test-core-hashtable.cpp
  unit/core/test-core-hdata.cpp
@@ -23,6 +23,7 @@ noinst_LIBRARIES = lib_weechat_unit_tests_core.a

 lib_weechat_unit_tests_core_a_SOURCES = unit/test-plugins.cpp \
                                        unit/core/test-core-arraylist.cpp \
+                                        unit/core/test-core-calc.cpp \
                                        unit/core/test-core-eval.cpp \
                                        unit/core/test-core-hashtable.cpp \
                                        unit/core/test-core-hdata.cpp \
@@ -61,6 +61,7 @@ extern "C"
 /* core */
 IMPORT_TEST_GROUP(Plugins);
 IMPORT_TEST_GROUP(CoreArraylist);
+IMPORT_TEST_GROUP(CoreCalc);
 IMPORT_TEST_GROUP(CoreEval);
 IMPORT_TEST_GROUP(CoreHashtable);
 IMPORT_TEST_GROUP(CoreHdata);
@@ -0,0 +1,111 @@
+/*
+ * test-core-calc.cpp - test calculations functions
+ *
+ * Copyright (C) 2019 Sébastien 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 <https://www.gnu.org/licenses/>.
+ */
+
+#include "CppUTest/TestHarness.h"
+
+extern "C"
+{
+#include "src/core/wee-calc.h"
+}
+
+#define WEE_CHECK_CALC(__result, __expr)                                \
+    value = calc_expression (__expr);                                   \
+    STRCMP_EQUAL(__result, value);                                      \
+    free (value);
+
+TEST_GROUP(CoreCalc)
+{
+};
+
+/*
+ * Tests functions:
+ *   calc_expression
+ */
+
+TEST(CoreCalc, Expression)
+{
+    char *value;
+
+    /* invalid expressions */
+    WEE_CHECK_CALC("0", NULL);
+    WEE_CHECK_CALC("0", "");
+    WEE_CHECK_CALC("0", "(");
+    WEE_CHECK_CALC("0", ")");
+    WEE_CHECK_CALC("0", "+");
+    WEE_CHECK_CALC("0", "-");
+    WEE_CHECK_CALC("0", "*");
+    WEE_CHECK_CALC("0", "/");
+    WEE_CHECK_CALC("0", "0/0");
+    WEE_CHECK_CALC("0", "0//0");
+    WEE_CHECK_CALC("0", "0%0");
+
+    /* no operator */
+    WEE_CHECK_CALC("123", "123");
+    WEE_CHECK_CALC("-2", "-2");
+    WEE_CHECK_CALC("1.5", "1.5");
+
+    /* addition */
+    WEE_CHECK_CALC("-3", "-4+1");
+    WEE_CHECK_CALC("3", "1+2");
+    WEE_CHECK_CALC("4", " 1  +  3 ");
+
+    /* subtraction */
+    WEE_CHECK_CALC("5", "8-3");
+    WEE_CHECK_CALC("-5", "3-8");
+
+    /* multiplication */
+    WEE_CHECK_CALC("20", "10*2");
+    WEE_CHECK_CALC("-8", "-2*4");
+    WEE_CHECK_CALC("152415765279684", "12345678*12345678");
+
+    /* division */
+    WEE_CHECK_CALC("2", "6/3");
+    WEE_CHECK_CALC("2.5", "10/4");
+
+    /* floor division */
+    WEE_CHECK_CALC("2", "10//4");
+
+    /* modulo */
+    WEE_CHECK_CALC("4", "9%5");
+    WEE_CHECK_CALC("0.2", "9.2%3");
+
+    /* multiple operators */
+    WEE_CHECK_CALC("11", "5+2*3");
+
+    /* expressions with decimal numbers */
+    WEE_CHECK_CALC("12.5", "10.5+2");
+    WEE_CHECK_CALC("3.3333333333", "10/3");
+    WEE_CHECK_CALC("0.1428571429", "1/7");
+    WEE_CHECK_CALC("0.0008103728", "1/1234");
+    WEE_CHECK_CALC("0.0000810045", "1/12345");
+    WEE_CHECK_CALC("0.0000081001", "1/123456");
+    WEE_CHECK_CALC("0.00000081", "1/1234567");
+    WEE_CHECK_CALC("0.000000081", "1/12345678");
+    WEE_CHECK_CALC("0.0000000081", "1/123456789");
+    WEE_CHECK_CALC("0.0000000008", "1/1234567890");
+    WEE_CHECK_CALC("0.0000000001", "1/12345678901");
+    WEE_CHECK_CALC("0", "1/123456789012");
+
+    /* expressions with parentheses */
+    WEE_CHECK_CALC("21", "(5+2)*3");
+    WEE_CHECK_CALC("3.15", "(1.5+2)*(1.8/2)");
+    WEE_CHECK_CALC("-1.26", "(1.5+2)*(1.8/(2-7))");
+}
@@ -145,6 +145,8 @@ TEST(CoreEval, EvalCondition)
    WEE_CHECK_EVAL("0", "${test2} == value2");
    WEE_CHECK_EVAL("0", "${buffer.number} == 2");
    WEE_CHECK_EVAL("0", "${window.buffer.number} == 2");
+    WEE_CHECK_EVAL("0", "${calc:2+3} < 5");
+    WEE_CHECK_EVAL("0", "${calc:1.5*3} < 4.5");

    /* conditions evaluated as true */
    WEE_CHECK_EVAL("1", "1");
@@ -203,6 +205,8 @@ TEST(CoreEval, EvalCondition)
    WEE_CHECK_EVAL("1", "${test2} ==");
    WEE_CHECK_EVAL("1", "${buffer.number} == 1");
    WEE_CHECK_EVAL("1", "${window.buffer.number} == 1");
+    WEE_CHECK_EVAL("1", "${calc:2+3} >= 5");
+    WEE_CHECK_EVAL("1", "${calc:1.5*3} >= 4.5");

    /* evaluation of extra_vars */
    hashtable_set (options, "extra", "eval");
@@ -407,6 +411,14 @@ TEST(CoreEval, EvalExpression)
    WEE_CHECK_EVAL("0", "${if:${rev:${if:42==42?hello:bye}}==eyb}");
    WEE_CHECK_EVAL("1", "${if:${rev:${if:42==42?hello:bye}}==olleh}");

+    /* test calc */
+    WEE_CHECK_EVAL("0", "${calc:}");
+    WEE_CHECK_EVAL("123", "${calc:123}");
+    WEE_CHECK_EVAL("4", "${calc:1+3}");
+    WEE_CHECK_EVAL("8", "${calc:5+1*3}");
+    WEE_CHECK_EVAL("18", "${calc:(5+1)*3}");
+    WEE_CHECK_EVAL("123129", "${calc:${repeat:2,123}+2*3}");
+
    /* test option */
    snprintf (str_value, sizeof (str_value),
              "%d", CONFIG_INTEGER(config_look_scroll_amount));