api: add argument "options" in function string_eval_expression, add option "-c" for command /eval (to evaluate a condition)

8 files changed, 245 insertions, 191 deletions

diff --git a/doc/de/autogen/user/weechat_commands.txt b/doc/de/autogen/user/weechat_commands.txt
index dde392745..d67b971ce 100644
--- a/doc/de/autogen/user/weechat_commands.txt
+++ b/doc/de/autogen/user/weechat_commands.txt
@@ -207,55 +207,56 @@ infolists: zeigt Information über die Infolists an
 [command]*`eval`* wertet einen Ausdruck aus und gibt das Resultat im Buffer aus::
 ........................................
 /eval  [-n] <expression>
-       [-n] <expression1> <operator> <expression2>
-
-        -n: zeigt das Ergebnis an, ohne das dieses in den Buffer geschrieben wird (debug Modus)
-expression: Ausdruck welcher verarbeitet werden soll. Variablen im Format ${variable} werden ersetzt (siehe unten)
-  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 Ausdruck überein
-                !~  stimmt NICHT mit regulärem Ausdruck überein
-
-Ein Ausdruck gilt als "wahr", sofern das Ergebnis nicht NULL, nicht leer und von "0" abweichend ist.
-Der Vergleich findet zwischen zwei Integer Werten statt, sofern die beiden Ausdrücke gültige Integer-Werte sind.
-Um einen Vergleich zwischen zwei Zeichenketten zu erzwingen, müssen die Ausdrücke in Anführungszeichen gesetzt werden, zum Beispiel:
+       [-n] -c <expression1> <operator> <expression2>
+
+        -n: display result without sending it to buffer (debug mode)
+        -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)
+  operator: a logical or comparison operator:
+            - logical operators:
+                &&  boolean "and"
+                ||  boolean "or"
+            - comparison operators:
+                ==  equal
+                !=  not equal
+                <=  less or equal
+                <   less
+                >=  greater or equal
+                >   greater
+                =~  is matching regex
+                !~  is NOT matching regex
+
+An expression is considered as "true" if it is not NULL, not empty, and different from "0".
+The comparison is made using integers if the two expressions are valid integers.
+To force a string comparison, add double quotes around each expression, for example:
   50 > 100      ==> 0
   "50" > "100"  ==> 1
 
-Einige Variablen werden im Ausdruck, mittels der Formatierung ${Variable}, ersetzt. Mögliche Variablen sind, nach Reihenfolge ihrer Priorität:
-  1. der Name einer Option (file.section.option)
-  2. der Name der lokalen Variablen für Buffer
-  3. ein hdata Name/Variable (der Wert wird automatisch als Zeichenkette konvertiert), Standardmäßig wird für "window" und "buffer" das aktuelle Fenster/Buffer verwendet.
-Das Format für hdata:
-  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
-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. the name of an option (file.section.option)
+  2. the name of a local variable in buffer
+  3. a hdata name/variable (the value is automatically converted to string), by default "window" and "buffer" point to current window/buffer.
+Format for hdata can be one of following:
+  hdata.var1.var2...: start with a hdata (pointer must be known), and ask variables one after one (other hdata can be followed)
+  hdata[list].var1.var2...: start with a hdata using a list, for example:
+    ${buffer[gui_buffers].full_name}: full name of first buffer in linked list of buffers
+    ${plugin[weechat_plugins].name}: name of first plugin in linked list of plugins
+For name of hdata and variables, please look at "Plugin API reference", function "weechat_hdata_get".
 
-Beispiele:
-  /eval -n ${weechat.look.scroll_amount}  ==> 3
-  /eval -n ${window}                      ==> 0x2549aa0
-  /eval -n ${window.buffer}               ==> 0x2549320
-  /eval -n ${window.buffer.full_name}     ==> core.weechat
-  /eval -n ${window.buffer.number}        ==> 1
-  /eval -n ${window.buffer.number} > 2    ==> 0
-  /eval -n ${window.win_width} > 100      ==> 1
-  /eval -n (8 > 12) || (5 > 2)            ==> 1
-  /eval -n (8 > 12) && (5 > 2)            ==> 0
-  /eval -n abcd =~ ^ABC                   ==> 1
-  /eval -n abcd =~ (?-i)^ABC              ==> 0
-  /eval -n abcd =~ (?-i)^abc              ==> 1
-  /eval -n abcd !~ abc                    ==> 0
+Examples:
+  /eval -n ${weechat.look.scroll_amount}   ==> 3
+  /eval -n ${window}                       ==> 0x2549aa0
+  /eval -n ${window.buffer}                ==> 0x2549320
+  /eval -n ${window.buffer.full_name}      ==> core.weechat
+  /eval -n ${window.buffer.number}         ==> 1
+  /eval -n -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
 ........................................
 
 [[command_weechat_filter]]
diff --git a/doc/en/autogen/user/weechat_commands.txt b/doc/en/autogen/user/weechat_commands.txt
index 992e470b6..0885078d3 100644
--- a/doc/en/autogen/user/weechat_commands.txt
+++ b/doc/en/autogen/user/weechat_commands.txt
@@ -207,9 +207,10 @@ infolists: display infos about infolists
 [command]*`eval`* evaluate expression and send result to buffer::
 ........................................
 /eval  [-n] <expression>
-       [-n] <expression1> <operator> <expression2>
+       [-n] -c <expression1> <operator> <expression2>
 
         -n: display result without sending it to buffer (debug mode)
+        -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)
   operator: a logical or comparison operator:
             - logical operators:
@@ -243,19 +244,19 @@ Format for hdata can be one of following:
 For name of hdata and variables, please look at "Plugin API reference", function "weechat_hdata_get".
 
 Examples:
-  /eval -n ${weechat.look.scroll_amount}  ==> 3
-  /eval -n ${window}                      ==> 0x2549aa0
-  /eval -n ${window.buffer}               ==> 0x2549320
-  /eval -n ${window.buffer.full_name}     ==> core.weechat
-  /eval -n ${window.buffer.number}        ==> 1
-  /eval -n ${window.buffer.number} > 2    ==> 0
-  /eval -n ${window.win_width} > 100      ==> 1
-  /eval -n (8 > 12) || (5 > 2)            ==> 1
-  /eval -n (8 > 12) && (5 > 2)            ==> 0
-  /eval -n abcd =~ ^ABC                   ==> 1
-  /eval -n abcd =~ (?-i)^ABC              ==> 0
-  /eval -n abcd =~ (?-i)^abc              ==> 1
-  /eval -n abcd !~ abc                    ==> 0
+  /eval -n ${weechat.look.scroll_amount}   ==> 3
+  /eval -n ${window}                       ==> 0x2549aa0
+  /eval -n ${window.buffer}                ==> 0x2549320
+  /eval -n ${window.buffer.full_name}      ==> core.weechat
+  /eval -n ${window.buffer.number}         ==> 1
+  /eval -n -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
 ........................................
 
 [[command_weechat_filter]]
diff --git a/doc/en/weechat_plugin_api.en.txt b/doc/en/weechat_plugin_api.en.txt
index 30e162daa..03e042876 100644
--- a/doc/en/weechat_plugin_api.en.txt
+++ b/doc/en/weechat_plugin_api.en.txt
@@ -1699,7 +1699,7 @@ str3 = weechat.string_input_for_buffer("//test") # "/test"
 weechat_string_eval_expression
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-_New in version 0.4.0._
+_New in version 0.4.0, updated in 0.4.2._
 
 Evaluate an expression and return result as a string.
 Special variables with format `${variable}` are expanded (see command `/eval` in
@@ -1711,7 +1711,8 @@ Prototype:
 ----------------------------------------
 char *weechat_string_eval_expression (const char *expr,
                                       struct t_hashtable *pointers,
-                                      struct t_hashtable *extra_vars);
+                                      struct t_hashtable *extra_vars,
+                                      struct t_hashtable *options);
 ----------------------------------------
 
 Arguments:
@@ -1721,6 +1722,14 @@ Arguments:
   pointer); pointers "window" and "buffer" are automatically added if they are
   not in hashtable (with pointer to current window/buffer) (can be NULL)
 * 'extra_vars': extra variables that will be expanded (can be NULL)
+* 'options': a hashtable with some options (keys and values must be string)
+  (can be NULL):
+** 'type': default behaviour is just to replace values in expression, other
+   types can be selected:
+*** 'condition': the expression is evaluated as a condition: operators and
+    parentheses are used, result is a boolean ("0" or "1")
+** 'prefix': prefix before variables to replace (default: "${")
+** 'suffix': suffix after variables to replace (default: "}")
 
 Return value:
 
@@ -1731,9 +1740,16 @@ C examples:
 
 [source,C]
 ----------------------------------------
-char *str1 = weechat_string_eval_expression ("${buffer.full_name}", NULL, NULL);       /* "core.weechat" */
-char *str2 = weechat_string_eval_expression ("${window.win_width} > 100", NULL, NULL); /* "1" */
-char *str3 = weechat_string_eval_expression ("abc =~ def", NULL, NULL);                /* "0" */
+struct t_hashtable *options = weechat_hashtable_new (8,
+                                                     WEECHAT_HASHTABLE_STRING,
+                                                     WEECHAT_HASHTABLE_STRING,
+                                                     NULL,
+                                                     NULL);
+if (options)
+    weechat_hashtable_set (options, "type", "condition");
+char *str1 = weechat_string_eval_expression ("${buffer.full_name}", NULL, NULL, NULL);          /* "core.weechat" */
+char *str2 = weechat_string_eval_expression ("${window.win_width} > 100", NULL, NULL, options); /* "1" */
+char *str3 = weechat_string_eval_expression ("abc =~ def", NULL, NULL, options);                /* "0" */
 ----------------------------------------
 
 Script (Python):
@@ -1741,12 +1757,12 @@ Script (Python):
 [source,python]
 ----------------------------------------
 # prototype
-str = weechat.string_eval_expression(expr, pointers, extra_vars)
+str = weechat.string_eval_expression(expr, pointers, extra_vars, options)
 
 # examples
-str1 = weechat.string_eval_expression("${buffer.full_name}", {}, {})       # "core.weechat"
-str2 = weechat.string_eval_expression("${window.win_width} > 100", {}, {}) # "1"
-str3 = weechat.string_eval_expression("abc =~ def", {}, {})                # "0"
+str1 = weechat.string_eval_expression("${buffer.full_name}", {}, {}, {})                          # "core.weechat"
+str2 = weechat.string_eval_expression("${window.win_width} > 100", {}, {}, {"type": "condition"}) # "1"
+str3 = weechat.string_eval_expression("abc =~ def", {}, {}, {"type": "condition"})                # "0"
 ----------------------------------------
 
 [[utf-8]]
diff --git a/doc/fr/autogen/user/weechat_commands.txt b/doc/fr/autogen/user/weechat_commands.txt
index ad4d214c0..6752c7592 100644
--- a/doc/fr/autogen/user/weechat_commands.txt
+++ b/doc/fr/autogen/user/weechat_commands.txt
@@ -207,9 +207,10 @@ infolists: afficher des infos sur les infolists
 [command]*`eval`* évaluer une expression et envoyer le résultat au tampon::
 ........................................
 /eval  [-n] <expression>
-       [-n] <expression1> <opérateur> <expression2>
+       [-n] -c <expression1> <opérateur> <expression2>
 
         -n: afficher le résultat sans envoyer au tampon (mode debug)
+        -c: évaluer comme une condition : utiliser les opérateurs et les parenthèses, retourner une valeur booléenne ("0" ou "1")
 expression: expression à évaluer, les variables avec le format ${variable} sont remplacées (voir ci-dessous)
  opérateur: un opérateur logique ou de comparaison :
             - opérateurs logiques :
@@ -243,19 +244,19 @@ Le format du hdata peut être le suivant :
 Pour le nom du hdata et des variables, voir la "Référence API extension", fonction "weechat_hdata_get".
 
 Exemples:
-  /eval -n ${weechat.look.scroll_amount}  ==> 3
-  /eval -n ${window}                      ==> 0x2549aa0
-  /eval -n ${window.buffer}               ==> 0x2549320
-  /eval -n ${window.buffer.full_name}     ==> core.weechat
-  /eval -n ${window.buffer.number}        ==> 1
-  /eval -n ${window.buffer.number} > 2    ==> 0
-  /eval -n ${window.win_width} > 100      ==> 1
-  /eval -n (8 > 12) || (5 > 2)            ==> 1
-  /eval -n (8 > 12) && (5 > 2)            ==> 0
-  /eval -n abcd =~ ^ABC                   ==> 1
-  /eval -n abcd =~ (?-i)^ABC              ==> 0
-  /eval -n abcd =~ (?-i)^abc              ==> 1
-  /eval -n abcd !~ abc                    ==> 0
+  /eval -n ${weechat.look.scroll_amount}   ==> 3
+  /eval -n ${window}                       ==> 0x2549aa0
+  /eval -n ${window.buffer}                ==> 0x2549320
+  /eval -n ${window.buffer.full_name}      ==> core.weechat
+  /eval -n ${window.buffer.number}         ==> 1
+  /eval -n -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
 ........................................
 
 [[command_weechat_filter]]
diff --git a/doc/fr/weechat_plugin_api.fr.txt b/doc/fr/weechat_plugin_api.fr.txt
index 5db4d9c16..72df89327 100644
--- a/doc/fr/weechat_plugin_api.fr.txt
+++ b/doc/fr/weechat_plugin_api.fr.txt
@@ -1723,7 +1723,7 @@ str3 = weechat.string_input_for_buffer("//test") # "/test"
 weechat_string_eval_expression
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-_Nouveau dans la version 0.4.0._
+_Nouveau dans la version 0.4.0, mis à jour dans la 0.4.2._
 
 Evalue l'expression et retourne le résultat sous forme de chaîne.
 Les variables spéciales avec le format `${variable}` sont étendues (voir la
@@ -1735,7 +1735,8 @@ Prototype :
 ----------------------------------------
 char *weechat_string_eval_expression (const char *expr,
                                       struct t_hashtable *pointers,
-                                      struct t_hashtable *extra_vars);
+                                      struct t_hashtable *extra_vars,
+                                      struct t_hashtable *options);
 ----------------------------------------
 
 Paramètres :
@@ -1746,6 +1747,14 @@ Paramètres :
   sont automatiquement ajoutés s'ils ne sont pas dans la hashtable (avec le
   pointer vers fenêtre/tampon courants) (peut être NULL)
 * 'extra_vars' : variables additionnelles qui seront étendues (peut être NULL)
+* 'options' : hashtable avec des options (les clés et valeurs doivent être des
+  des chaînes) (peut être NULL) :
+** 'type' : le comportement par défaut est de juste remplacer les valeurs dans
+   l'expression, d'autres types peuvent être choisis :
+*** 'condition' : l'expression est évaluée comme une condition : les opérateurs
+    et parenthèses sont utilisés, le résultat est un booléen ("0" ou "1")
+** 'prefix' : préfixe avant les variables à remplacer (par défaut: "${")
+** 'suffix' : suffixe après les variables à remplacer (par défaut: "}")
 
 Valeur de retour :
 
@@ -1757,9 +1766,16 @@ Exemples en C :
 
 [source,C]
 ----------------------------------------
-char *str1 = weechat_string_eval_expression ("${buffer.full_name}", NULL, NULL);       /* "core.weechat" */
-char *str2 = weechat_string_eval_expression ("${window.win_width} > 100", NULL, NULL); /* "1" */
-char *str3 = weechat_string_eval_expression ("abc =~ def", NULL, NULL);                /* "0" */
+struct t_hashtable *options = weechat_hashtable_new (8,
+                                                     WEECHAT_HASHTABLE_STRING,
+                                                     WEECHAT_HASHTABLE_STRING,
+                                                     NULL,
+                                                     NULL);
+if (options)
+    weechat_hashtable_set (options, "type", "condition");
+char *str1 = weechat_string_eval_expression ("${buffer.full_name}", NULL, NULL, NULL);          /* "core.weechat" */
+char *str2 = weechat_string_eval_expression ("${window.win_width} > 100", NULL, NULL, options); /* "1" */
+char *str3 = weechat_string_eval_expression ("abc =~ def", NULL, NULL, options);                /* "0" */
 ----------------------------------------
 
 Script (Python) :
@@ -1767,12 +1783,12 @@ Script (Python) :
 [source,python]
 ----------------------------------------
 # prototype
-str = weechat.string_eval_expression(expr, pointers, extra_vars)
+str = weechat.string_eval_expression(expr, pointers, extra_vars, options)
 
 # exemples
-str1 = weechat.string_eval_expression("${buffer.full_name}", {}, {})       # "core.weechat"
-str2 = weechat.string_eval_expression("${window.win_width} > 100", {}, {}) # "1"
-str3 = weechat.string_eval_expression("abc =~ def", {}, {})                # "0"
+str1 = weechat.string_eval_expression("${buffer.full_name}", {}, {}, {})                          # "core.weechat"
+str2 = weechat.string_eval_expression("${window.win_width} > 100", {}, {}, {"type": "condition"}) # "1"
+str3 = weechat.string_eval_expression("abc =~ def", {}, {}, {"type": "condition"})                # "0"
 ----------------------------------------
 
 [[utf-8]]
diff --git a/doc/it/autogen/user/weechat_commands.txt b/doc/it/autogen/user/weechat_commands.txt
index 21207d11a..e58f4e8a6 100644
--- a/doc/it/autogen/user/weechat_commands.txt
+++ b/doc/it/autogen/user/weechat_commands.txt
@@ -206,56 +206,57 @@ infolists: mostra informazioni sulle liste info
 [[command_weechat_eval]]
 [command]*`eval`* analizza l'espressione e invia il risultato al buffer::
 ........................................
-/eval  [-n] <espressione>
-       [-n] <espressione1> <operatore> <espressione2>
-
-         -n: mostra il risultato senza inviarlo al buffer (modalità debug)
-espressione: espressione da analizzare, le variabili con il formato ${variable} vengono sostituite (vedere sotto)
- operatore: operatore logico o di confronto:
-            - operatori logici:
-                &&  "and" booleano
-                ||  "or" booleano
-            - operatori di confronto:
-                ==  uguale
-                !=  non uguale
-                <=  minore o uguale
-                <   minore
-                >=  maggiore o uguale
-                >   maggiore
-                =~  corrisponde alla regex
-                !~  NON corrisponde alla regex
-
-Un'espressione è considerata come "true" se non è NULL, non vuota, e diversa da "0".
-Il confronto viene fatto usando gli interi se le due espressioni sono interi validi.
-Per forzare il confronto stringa, aggiungere un doppio apice all'espressione, ad esempio:
+/eval  [-n] <expression>
+       [-n] -c <expression1> <operator> <expression2>
+
+        -n: display result without sending it to buffer (debug mode)
+        -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)
+  operator: a logical or comparison operator:
+            - logical operators:
+                &&  boolean "and"
+                ||  boolean "or"
+            - comparison operators:
+                ==  equal
+                !=  not equal
+                <=  less or equal
+                <   less
+                >=  greater or equal
+                >   greater
+                =~  is matching regex
+                !~  is NOT matching regex
+
+An expression is considered as "true" if it is not NULL, not empty, and different from "0".
+The comparison is made using integers if the two expressions are valid integers.
+To force a string comparison, add double quotes around each expression, for example:
   50 > 100      ==> 0
   "50" > "100"  ==> 1
 
-Alcune variabili vengono sostituite nell'espressione, usando il formato ${variable}, la variabile può essere, in ordine di priorità :
-  1. il nome di un'opzione (file.sezione.opzione)
-  2. il nome di una variabile locale nel buffer
-  3. un nome/variabile hdata (il valore viene automaticamente convertito in stringa, per default "window" e "buffer" puntano alla finestra/buffer correnti.
-Il formato per hdata può essere uno dei seguenti:
-  hdata.var1.var2...: inizia con un hdata (il puntatore deve essere noto), e richiedere le variabili a seguire (possono seguire altri hdata)
-  hdata[list].var1.var2...: inizia con un hdata usando una lista, ad esempio:
-    ${buffer[gui_buffers].full_name}: nome completo del primo buffer nell'elenco collegato dei buffer
-    ${plugin[weechat_plugins].name}: nome del primo plugin nell'elenco collegato dei plugin
-Per il nome degli hdata e delle variabili, per favore consultare "Referenze API per Plugin", funzione "weechat_hdata_get".
+Some variables are replaced in expression, using the format ${variable}, variable can be, by order of priority :
+  1. the name of an option (file.section.option)
+  2. the name of a local variable in buffer
+  3. a hdata name/variable (the value is automatically converted to string), by default "window" and "buffer" point to current window/buffer.
+Format for hdata can be one of following:
+  hdata.var1.var2...: start with a hdata (pointer must be known), and ask variables one after one (other hdata can be followed)
+  hdata[list].var1.var2...: start with a hdata using a list, for example:
+    ${buffer[gui_buffers].full_name}: full name of first buffer in linked list of buffers
+    ${plugin[weechat_plugins].name}: name of first plugin in linked list of plugins
+For name of hdata and variables, please look at "Plugin API reference", function "weechat_hdata_get".
 
-Esempi:
-  /eval -n ${weechat.look.scroll_amount}  ==> 3
-  /eval -n ${window}                      ==> 0x2549aa0
-  /eval -n ${window.buffer}               ==> 0x2549320
-  /eval -n ${window.buffer.full_name}     ==> core.weechat
-  /eval -n ${window.buffer.number}        ==> 1
-  /eval -n ${window.buffer.number} > 2    ==> 0
-  /eval -n ${window.win_width} > 100      ==> 1
-  /eval -n (8 > 12) || (5 > 2)            ==> 1
-  /eval -n (8 > 12) && (5 > 2)            ==> 0
-  /eval -n abcd =~ ^ABC                   ==> 1
-  /eval -n abcd =~ (?-i)^ABC              ==> 0
-  /eval -n abcd =~ (?-i)^abc              ==> 1
-  /eval -n abcd !~ abc                    ==> 0
+Examples:
+  /eval -n ${weechat.look.scroll_amount}   ==> 3
+  /eval -n ${window}                       ==> 0x2549aa0
+  /eval -n ${window.buffer}                ==> 0x2549320
+  /eval -n ${window.buffer.full_name}      ==> core.weechat
+  /eval -n ${window.buffer.number}         ==> 1
+  /eval -n -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
 ........................................
 
 [[command_weechat_filter]]
diff --git a/doc/it/weechat_plugin_api.it.txt b/doc/it/weechat_plugin_api.it.txt
index ceee1ac49..e2267e4a6 100644
--- a/doc/it/weechat_plugin_api.it.txt
+++ b/doc/it/weechat_plugin_api.it.txt
@@ -1683,7 +1683,8 @@ str3 = weechat.string_input_for_buffer("//test") # "/test"
 weechat_string_eval_expression
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-_Novità nella versione 0.4.0._
+// TRANSLATION MISSING
+_Novità nella versione 0.4.0, updated in 0.4.2._
 
 // TRANSLATION MISSING
 Evaluate an expression and return result as a string.
@@ -1696,7 +1697,8 @@ Prototipo:
 ----------------------------------------
 char *weechat_string_eval_expression (const char *expr,
                                       struct t_hashtable *pointers,
-                                      struct t_hashtable *extra_vars);
+                                      struct t_hashtable *extra_vars,
+                                      struct t_hashtable *options);
 ----------------------------------------
 
 Argomenti:
@@ -1707,6 +1709,14 @@ Argomenti:
   pointer); pointers "window" and "buffer" are automatically added if they are
   not in hashtable (with pointer to current window/buffer) (can be NULL)
 * 'extra_vars': extra variables that will be expanded (can be NULL)
+* 'options': a hashtable with some options (keys and values must be string)
+  (can be NULL):
+** 'type': default behaviour is just to replace values in expression, other
+   types can be selected:
+*** 'condition': the expression is evaluated as a condition: operators and
+    parentheses are used, result is a boolean ("0" or "1")
+** 'prefix': prefix before variables to replace (default: "${")
+** 'suffix': suffix after variables to replace (default: "}")
 
 Valore restituito:
 
@@ -1718,9 +1728,16 @@ Esempi in C:
 
 [source,C]
 ----------------------------------------
-char *str1 = weechat_string_eval_expression ("${buffer.full_name}", NULL, NULL);       /* "core.weechat" */
-char *str2 = weechat_string_eval_expression ("${window.win_width} > 100", NULL, NULL); /* "1" */
-char *str3 = weechat_string_eval_expression ("abc =~ def", NULL, NULL);                /* "0" */
+struct t_hashtable *options = weechat_hashtable_new (8,
+                                                     WEECHAT_HASHTABLE_STRING,
+                                                     WEECHAT_HASHTABLE_STRING,
+                                                     NULL,
+                                                     NULL);
+if (options)
+    weechat_hashtable_set (options, "type", "condition");
+char *str1 = weechat_string_eval_expression ("${buffer.full_name}", NULL, NULL, NULL);          /* "core.weechat" */
+char *str2 = weechat_string_eval_expression ("${window.win_width} > 100", NULL, NULL, options); /* "1" */
+char *str3 = weechat_string_eval_expression ("abc =~ def", NULL, NULL, options);                /* "0" */
 ----------------------------------------
 
 Script (Python):
@@ -1728,12 +1745,12 @@ Script (Python):
 [source,python]
 ----------------------------------------
 # prototipo
-str = weechat.string_eval_expression(expr, pointers, extra_vars)
+str = weechat.string_eval_expression(expr, pointers, extra_vars, options)
 
 # esempi
-str1 = weechat.string_eval_expression("${buffer.full_name}", {}, {})       # "core.weechat"
-str2 = weechat.string_eval_expression("${window.win_width} > 100", {}, {}) # "1"
-str3 = weechat.string_eval_expression("abc =~ def", {}, {})                # "0"
+str1 = weechat.string_eval_expression("${buffer.full_name}", {}, {}, {})                          # "core.weechat"
+str2 = weechat.string_eval_expression("${window.win_width} > 100", {}, {}, {"type": "condition"}) # "1"
+str3 = weechat.string_eval_expression("abc =~ def", {}, {}, {"type": "condition"})                # "0"
 ----------------------------------------
 
 [[utf-8]]
diff --git a/doc/ja/autogen/user/weechat_commands.txt b/doc/ja/autogen/user/weechat_commands.txt
index 9e7a75043..fa4876108 100644
--- a/doc/ja/autogen/user/weechat_commands.txt
+++ b/doc/ja/autogen/user/weechat_commands.txt
@@ -207,55 +207,56 @@ infolists: infolist に関する情報を表示
 [command]*`eval`* 式を評価して結果をバッファに送信::
 ........................................
 /eval  [-n] <expression>
-       [-n] <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)
-expression: 評価する式、フォーマット、${variable} 型のフォーマットの変数は置換されます (以下を参照)
-  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
-                =~  正規表現にマッチ
-                !~  正規表現にマッチしない
-
-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。
-両方の式が有効な整数である場合、比較は整数を使って行われます。
-文字列比較を強制するには、それぞれの式をダブルクォートで囲みます、例えば:
+       [-n] -c <expression1> <operator> <expression2>
+
+        -n: display result without sending it to buffer (debug mode)
+        -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)
+  operator: a logical or comparison operator:
+            - logical operators:
+                &&  boolean "and"
+                ||  boolean "or"
+            - comparison operators:
+                ==  equal
+                !=  not equal
+                <=  less or equal
+                <   less
+                >=  greater or equal
+                >   greater
+                =~  is matching regex
+                !~  is NOT matching regex
+
+An expression is considered as "true" if it is not NULL, not empty, and different from "0".
+The comparison is made using integers if the two expressions are valid integers.
+To force a string comparison, add double quotes around each expression, for example:
   50 > 100      ==> 0
   "50" > "100"  ==> 1
 
-式中の ${variable} 型のフォーマットの変数は置換さます。変数は以下の優先順位に従います。
-  1. オプションの名前 (file.section.option)
-  2. バッファのローカル変数の名前
-  3. 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 のフォーマットは以下の 1 つです:
-  hdata.var1.var2...: hdata (ポインタは既知) で始まり、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...: リストを使って hdata を始める、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 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. the name of an option (file.section.option)
+  2. the name of a local variable in buffer
+  3. a hdata name/variable (the value is automatically converted to string), by default "window" and "buffer" point to current window/buffer.
+Format for hdata can be one of following:
+  hdata.var1.var2...: start with a hdata (pointer must be known), and ask variables one after one (other hdata can be followed)
+  hdata[list].var1.var2...: start with a hdata using a list, for example:
+    ${buffer[gui_buffers].full_name}: full name of first buffer in linked list of buffers
+    ${plugin[weechat_plugins].name}: name of first plugin in linked list of plugins
+For name of hdata and variables, please look at "Plugin API reference", function "weechat_hdata_get".
 
-例:
-  /eval -n ${weechat.look.scroll_amount}  ==> 3
-  /eval -n ${window}                      ==> 0x2549aa0
-  /eval -n ${window.buffer}               ==> 0x2549320
-  /eval -n ${window.buffer.full_name}     ==> core.weechat
-  /eval -n ${window.buffer.number}        ==> 1
-  /eval -n ${window.buffer.number} > 2    ==> 0
-  /eval -n ${window.win_width} > 100      ==> 1
-  /eval -n (8 > 12) || (5 > 2)            ==> 1
-  /eval -n (8 > 12) && (5 > 2)            ==> 0
-  /eval -n abcd =~ ^ABC                   ==> 1
-  /eval -n abcd =~ (?-i)^ABC              ==> 0
-  /eval -n abcd =~ (?-i)^abc              ==> 1
-  /eval -n abcd !~ abc                    ==> 0
+Examples:
+  /eval -n ${weechat.look.scroll_amount}   ==> 3
+  /eval -n ${window}                       ==> 0x2549aa0
+  /eval -n ${window.buffer}                ==> 0x2549320
+  /eval -n ${window.buffer.full_name}      ==> core.weechat
+  /eval -n ${window.buffer.number}         ==> 1
+  /eval -n -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
 ........................................
 
 [[command_weechat_filter]]