patch 9.1.0547: No way to get the arity of a Vim function

Problem:  No way to get the arity of a Vim function
          (Austin Ziegler)
Solution: Enhance get() Vim script function to return the function
          argument info using get(func, "arity") (LemonBoy)

fixes: #15097
closes: #15109

Signed-off-by: LemonBoy <thatlemon@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/builtin.txt

@@ -1,4 +1,4 @@
-*builtin.txt*	For Vim version 9.1.  Last change: 2024 Jun 23
+*builtin.txt*	For Vim version 9.1.  Last change: 2024 Jul 09
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -3574,7 +3574,7 @@ garbagecollect([{atexit}])				*garbagecollect()*
 		Return type: |String|
 
 
-get({list}, {idx} [, {default}])			*get()*
+get({list}, {idx} [, {default}])			*get()* *get()-list*
 		Get item {idx} from |List| {list}.  When this item is not
 		available return {default}.  Return zero when {default} is
 		omitted.
@@ -3583,7 +3583,7 @@ get({list}, {idx} [, {default}])			*get()*
 <
 		Return type: any, depending on {list}
 
-get({blob}, {idx} [, {default}])
+get({blob}, {idx} [, {default}])			*get()-blob*
 		Get byte {idx} from |Blob| {blob}.  When this byte is not
 		available return {default}.  Return -1 when {default} is
 		omitted.
@@ -3592,7 +3592,7 @@ get({blob}, {idx} [, {default}])
 <
 		Return type: |Number|
 
-get({dict}, {key} [, {default}])
+get({dict}, {key} [, {default}])			*get()-dict*
 		Get item with key {key} from |Dictionary| {dict}.  When this
 		item is not available return {default}.  Return zero when
 		{default} is omitted.  Useful example: >
@@ -3604,18 +3604,32 @@ get({dict}, {key} [, {default}])
 <
 		Return type: any, depending on {dict}
 
-get({func}, {what})
-		Get item {what} from Funcref {func}.  Possible values for
+get({func}, {what})					*get()-func*
+		Get item {what} from |Funcref| {func}.  Possible values for
 		{what} are:
-			"name"	The function name
-			"func"	The function
-			"dict"	The dictionary
-			"args"	The list with arguments
+		  "name"    The function name
+		  "func"    The function
+		  "dict"    The dictionary
+		  "args"    The list with arguments
+		  "arity"   A dictionary with information about the number of
+			    arguments accepted by the function (minus the
+			    {arglist}) with the following fields:
+				required    the number of positional arguments
+				optional    the number of optional arguments,
+					    in addition to the required ones
+				varargs     |TRUE| if the function accepts a
+					    variable number of arguments |...|
+
+				Note: There is no error, if the {arglist} of
+				the Funcref contains more arguments than the
+				Funcref expects, it's not validated.
+
 		Returns zero on error.
+
 		Preferably used as a |method|: >
 			myfunc->get(what)
 <
-		Return type: any, depending on {func}
+		Return type: any, depending on {func} and {what}
 
 							*getbufinfo()*
 getbufinfo([{buf}])

runtime/doc/tags

@@ -7783,6 +7783,10 @@ gdb-version	terminal.txt	/*gdb-version*
 ge	motion.txt	/*ge*
 gender-neutral	helphelp.txt	/*gender-neutral*
 get()	builtin.txt	/*get()*
+get()-blob	builtin.txt	/*get()-blob*
+get()-dict	builtin.txt	/*get()-dict*
+get()-func	builtin.txt	/*get()-func*
+get()-list	builtin.txt	/*get()-list*
 get-ms-debuggers	debug.txt	/*get-ms-debuggers*
 getbufinfo()	builtin.txt	/*getbufinfo()*
 getbufline()	builtin.txt	/*getbufline()*

runtime/doc/version9.txt

@@ -1,4 +1,4 @@
-*version9.txt*  For Vim version 9.1.  Last change: 2024 Jul 06
+*version9.txt*  For Vim version 9.1.  Last change: 2024 Jul 08
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -41577,6 +41577,8 @@ Changed~
 - 'nrformat' accepts the new "blank" suboption, to determine a signed or
   unsigned number based on whitespace in front of a minus sign.
 - allow to specify a priority when defining a new sign |:sign-define|
+- provide information about function arguments using the get(func, "arity")
+  function |get()-func|
 
 							*added-9.2*
 Added ~