core: add reverse of string in evaluation of expressions with "rev:" (closes #1200)

10 files changed, 175 insertions, 144 deletions

diff --git a/doc/de/autogen/user/weechat_commands.adoc b/doc/de/autogen/user/weechat_commands.adoc
index a4b8a506e..bee61ae61 100644
--- a/doc/de/autogen/user/weechat_commands.adoc
+++ b/doc/de/autogen/user/weechat_commands.adoc
@@ -261,63 +261,64 @@ 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)
-
-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, die folgendes Format haben müssen:
-  - 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:
+        -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)
+
+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. eine Farbe (Format: "color:xxx", siehe "Anleitung für API Erweiterung", Funktion "color")\n
-  6. eine Info (Format: "info:Name,Argumente", Argumente sind optional)
-  7. aktuelles Datum/Uhrzeit (Format: "date" oder "date:format")
-  8. eine Umgebungsvariable (Format: "env:XXX")
-  9. ein Dreifachoperand (Format: "if:Bedingung?Wert_falls_wahr:Wert_falls_unwahr")
-  10. eine Option (Format: "file.section.option")
-  11. der Name einer lokalen Variablen eines Buffer
-  12. 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
-
-Beispiele (einfache Zeichenketten):
+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 color (format: "color:xxx", see "Plugin API reference", function "color")
+  7. an info (format: "info:name,arguments", arguments are optional)
+  8. current date/time (format: "date" or "date:format")
+  9. an environment variable (format: "env:XXX")
+  10. a ternary operator (format: "if:condition?value_if_true:value_if_false")
+  11. an option (format: "file.section.option")
+  12. a local variable in buffer
+  13. 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".
+
+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
@@ -329,16 +330,16 @@ Beispiele (einfache Zeichenketten):
   /eval -n ${date:%H:%M:%S}                      ==> 07:46:40
   /eval -n ${if:${info:term_width}>80?big:small} ==> big
 
-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]]
diff --git a/doc/en/autogen/user/weechat_commands.adoc b/doc/en/autogen/user/weechat_commands.adoc
index 855a759d5..9e2d5ecd8 100644
--- a/doc/en/autogen/user/weechat_commands.adoc
+++ b/doc/en/autogen/user/weechat_commands.adoc
@@ -296,14 +296,15 @@ Some variables are replaced in expression, using the format ${variable}, variabl
   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 color (format: "color:xxx", see "Plugin API reference", function "color")
-  6. an info (format: "info:name,arguments", arguments are optional)
-  7. current date/time (format: "date" or "date:format")
-  8. an environment variable (format: "env:XXX")
-  9. a ternary operator (format: "if:condition?value_if_true:value_if_false")
-  10. an option (format: "file.section.option")
-  11. a local variable in buffer
-  12. a hdata name/variable (the value is automatically converted to string), by default "window" and "buffer" point to current window/buffer.
+  5. a reversed string (format: "rev:xxx")
+  6. a color (format: "color:xxx", see "Plugin API reference", function "color")
+  7. an info (format: "info:name,arguments", arguments are optional)
+  8. current date/time (format: "date" or "date:format")
+  9. an environment variable (format: "env:XXX")
+  10. a ternary operator (format: "if:condition?value_if_true:value_if_false")
+  11. an option (format: "file.section.option")
+  12. a local variable in buffer
+  13. 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:
diff --git a/doc/en/weechat_plugin_api.en.adoc b/doc/en/weechat_plugin_api.en.adoc
index d1e8500d3..9418922f8 100644
--- a/doc/en/weechat_plugin_api.en.adoc
+++ b/doc/en/weechat_plugin_api.en.adoc
@@ -2288,6 +2288,12 @@ expanded to last):
   `+thi…+` +
   `+こ>>+`
 
+| `+${rev:xxx}+` +
+  (_WeeChat ≥ 2.2_) |
+  Reversed string. |
+  `+${rev:Hello, world!}+` |
+  `+!dlrow ,olleH+`
+
 | `+${re:N}+` +
   (_WeeChat ≥ 1.1_) |
   Regex captured group: `0` = whole string matching, `1` to `99` = group
diff --git a/doc/fr/autogen/user/weechat_commands.adoc b/doc/fr/autogen/user/weechat_commands.adoc
index 34cc671cf..0a1a10e1e 100644
--- a/doc/fr/autogen/user/weechat_commands.adoc
+++ b/doc/fr/autogen/user/weechat_commands.adoc
@@ -296,14 +296,15 @@ Des variables sont remplacées dans l'expression, en utilisant le format ${varia
   3. une chaîne avec des caractères à cacher (format : "hide:caractère,chaîne")
   4. une chaîne avec un maximum de caractères (format : "cut:max,suffixe,chaîne" ou "cut:+max,suffixe,chaîne")
      ou un maximum de caractères affichés à l'écran (format : "cutscr:max,suffixe,chaîne" ou "cutscr:+max,suffixe,chaîne")
-  5. une couleur (format : "color:xxx", voir la "Référence API extension", fonction "color")
-  6. une info (format : "info:nom,paramètres", les paramètres sont optionnels)
-  7. la date/heure courante (format : "date" ou "date:format")
-  8. une variable d'environnement (format : "env:XXX")
-  9. un opérateur ternaire (format : "if:condition?valeur_si_vrai:valeur_si_faux")
-  10. une option (format : "fichier.section.option")
-  11. une variable locale du tampon
-  12. un hdata/variable (la valeur est automatiquement convertie en chaîne), par défaut "window" et "buffer" pointent vers la fenêtre et le tampon courants.
+  5. une chaîne inversée (format : "rev:xxx")
+  6. une couleur (format : "color:xxx", voir la "Référence API extension", fonction "color")
+  7. une info (format : "info:nom,paramètres", les paramètres sont optionnels)
+  8. la date/heure courante (format : "date" ou "date:format")
+  9. une variable d'environnement (format : "env:XXX")
+  10. un opérateur ternaire (format : "if:condition?valeur_si_vrai:valeur_si_faux")
+  11. une option (format : "fichier.section.option")
+  12. une variable locale du tampon
+  13. 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 :
diff --git a/doc/fr/weechat_plugin_api.fr.adoc b/doc/fr/weechat_plugin_api.fr.adoc
index 831b039d4..d9bd17109 100644
--- a/doc/fr/weechat_plugin_api.fr.adoc
+++ b/doc/fr/weechat_plugin_api.fr.adoc
@@ -2331,6 +2331,12 @@ première étendue à la dernière) :
   `+cec…+` +
   `+こ>>+`
 
+| `+${rev:xxx}+` +
+  (_WeeChat ≥ 2.2_) |
+  Chaîne inversée. |
+  `+${rev:Bonjour !}+` |
+  `+! ruojnoB+`
+
 | `+${re:N}+` +
   (_WeeChat ≥ 1.1_) |
   Groupe regex capturé : `0` = toute la chaîne correspondante,
diff --git a/doc/it/autogen/user/weechat_commands.adoc b/doc/it/autogen/user/weechat_commands.adoc
index 62e977628..e3541afb5 100644
--- a/doc/it/autogen/user/weechat_commands.adoc
+++ b/doc/it/autogen/user/weechat_commands.adoc
@@ -296,14 +296,15 @@ Some variables are replaced in expression, using the format ${variable}, variabl
   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 color (format: "color:xxx", see "Plugin API reference", function "color")
-  6. an info (format: "info:name,arguments", arguments are optional)
-  7. current date/time (format: "date" or "date:format")
-  8. an environment variable (format: "env:XXX")
-  9. a ternary operator (format: "if:condition?value_if_true:value_if_false")
-  10. an option (format: "file.section.option")
-  11. a local variable in buffer
-  12. a hdata name/variable (the value is automatically converted to string), by default "window" and "buffer" point to current window/buffer.
+  5. a reversed string (format: "rev:xxx")
+  6. a color (format: "color:xxx", see "Plugin API reference", function "color")
+  7. an info (format: "info:name,arguments", arguments are optional)
+  8. current date/time (format: "date" or "date:format")
+  9. an environment variable (format: "env:XXX")
+  10. a ternary operator (format: "if:condition?value_if_true:value_if_false")
+  11. an option (format: "file.section.option")
+  12. a local variable in buffer
+  13. 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:
diff --git a/doc/it/weechat_plugin_api.it.adoc b/doc/it/weechat_plugin_api.it.adoc
index 2c02fce47..2c17ed3d2 100644
--- a/doc/it/weechat_plugin_api.it.adoc
+++ b/doc/it/weechat_plugin_api.it.adoc
@@ -2381,6 +2381,12 @@ expanded to last):
   `+thi…+` +
   `+こ>>+`
 
+| `+${rev:xxx}+` +
+  (_WeeChat ≥ 2.2_) |
+  Reversed string. |
+  `+${rev:Hello, world!}+` |
+  `+!dlrow ,olleH+`
+
 | `+${re:N}+` +
   (_WeeChat ≥ 1.1_) |
   Regex captured group: `0` = whole string matching, `1` to `99` = group
diff --git a/doc/ja/autogen/user/weechat_commands.adoc b/doc/ja/autogen/user/weechat_commands.adoc
index 9eb3f405f..990c0a4b0 100644
--- a/doc/ja/autogen/user/weechat_commands.adoc
+++ b/doc/ja/autogen/user/weechat_commands.adoc
@@ -261,59 +261,60 @@ 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)
-
-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:
+        -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)
+
+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. 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)
-  6. 情報 (書式: "info:name,arguments"、arguments は任意)
-  7. 現在の日付/時刻 (書式: "date" または "date:format")
-  8. 環境変数 (書式: "env:XXX")
-  9. 三項演算子 (書式: "if:condition?value_if_true:value_if_false")
-  10. オプション (書式: "file.section.option")
-  11. バッファのローカル変数
-  12. 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。
-
-例 (単純な文字列):
+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 color (format: "color:xxx", see "Plugin API reference", function "color")
+  7. an info (format: "info:name,arguments", arguments are optional)
+  8. current date/time (format: "date" or "date:format")
+  9. an environment variable (format: "env:XXX")
+  10. a ternary operator (format: "if:condition?value_if_true:value_if_false")
+  11. an option (format: "file.section.option")
+  12. a local variable in buffer
+  13. 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".
+
+Examples (simple strings):
   /eval -n ${info:version}                       ==> 0.4.3
   /eval -n ${env:HOME}                           ==> /home/user
   /eval -n ${weechat.look.scroll_amount}         ==> 3
@@ -329,7 +330,7 @@ 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 ${date:%H:%M:%S}                      ==> 07:46:40
   /eval -n ${if:${info:term_width}>80?big:small} ==> big
 
-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
diff --git a/doc/ja/weechat_plugin_api.ja.adoc b/doc/ja/weechat_plugin_api.ja.adoc
index f40553ecf..b955b6df5 100644
--- a/doc/ja/weechat_plugin_api.ja.adoc
+++ b/doc/ja/weechat_plugin_api.ja.adoc
@@ -2292,6 +2292,13 @@ str5 = weechat.string_eval_expression("password=abc password=def", {}, {}, optio
   `+thi…+` +
   `+こ>>+`
 
+// TRANSLATION MISSING
+| `+${rev:xxx}+` +
+  (_WeeChat ≥ 2.2_) |
+  Reversed string. |
+  `+${rev:Hello, world!}+` |
+  `+!dlrow ,olleH+`
+
 | `+${re:N}+` +
   (_WeeChat バージョン 1.1 以上で利用可_) |
   正規表現のキャプチャグループ: `0` = マッチするすべての文字列、`1` から `99` =
diff --git a/doc/pl/autogen/user/weechat_commands.adoc b/doc/pl/autogen/user/weechat_commands.adoc
index 6d0afbf17..808c88a8a 100644
--- a/doc/pl/autogen/user/weechat_commands.adoc
+++ b/doc/pl/autogen/user/weechat_commands.adoc
@@ -296,14 +296,15 @@ Some variables are replaced in expression, using the format ${variable}, variabl
   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 color (format: "color:xxx", see "Plugin API reference", function "color")
-  6. an info (format: "info:name,arguments", arguments are optional)
-  7. current date/time (format: "date" or "date:format")
-  8. an environment variable (format: "env:XXX")
-  9. a ternary operator (format: "if:condition?value_if_true:value_if_false")
-  10. an option (format: "file.section.option")
-  11. a local variable in buffer
-  12. a hdata name/variable (the value is automatically converted to string), by default "window" and "buffer" point to current window/buffer.
+  5. a reversed string (format: "rev:xxx")
+  6. a color (format: "color:xxx", see "Plugin API reference", function "color")
+  7. an info (format: "info:name,arguments", arguments are optional)
+  8. current date/time (format: "date" or "date:format")
+  9. an environment variable (format: "env:XXX")
+  10. a ternary operator (format: "if:condition?value_if_true:value_if_false")
+  11. an option (format: "file.section.option")
+  12. a local variable in buffer
+  13. 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: