patch 8.2.1255: cannot use a lambda with quickfix functionsv8.2.1255

Problem:    Cannot use a lambda with quickfix functions.
Solution:   Add support for lambda. (Yegappan Lakshmanan, closes #6499)

3 files changed, 13 insertions, 7 deletions

diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 5be18bd796..ed4f8aab0e 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -1,4 +1,4 @@
-*eval.txt*	For Vim version 8.2.  Last change: 2020 Jul 09
+*eval.txt*	For Vim version 8.2.  Last change: 2020 Jul 19
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -94,8 +94,9 @@ the Number.  Examples:
 	Number 0	-->	String "0" ~
 	Number -1	-->	String "-1" ~
 							*octal*
-Conversion from a String to a Number is done by converting the first digits to
-a number.  Hexadecimal "0xf9", Octal "017" or "0o17", and Binary "0b10"
+Conversion from a String to a Number only happens in legacy Vim script, not in
+Vim9 script.  It is done by converting the first digits to a number.
+Hexadecimal "0xf9", Octal "017" or "0o17", and Binary "0b10"
 numbers are recognized (NOTE: when using |scriptversion-4| octal with a
 leading "0" is not recognized).  If the String doesn't start with digits, the
 result is zero.
@@ -2831,7 +2832,7 @@ stridx({haystack}, {needle} [, {start}])
 string({expr})			String	String representation of {expr} value
 strlen({expr})			Number	length of the String {expr}
 strpart({str}, {start} [, {len}])
-				String	{len} characters of {str} at {start}
+				String	{len} bytes of {str} at byte {start}
 strptime({format}, {timestring})
 				Number	Convert {timestring} to unix timestamp
 strridx({haystack}, {needle} [, {start}])
@@ -9183,7 +9184,8 @@ setqflist({list} [, {action} [, {what}]])		*setqflist()*
 				the last quickfix list.
 		    quickfixtextfunc
 				function to get the text to display in the
-				quickfix window.  Refer to
+				quickfix window.  The value can be the name of
+				a function or a funcref or a lambda.  Refer to
 				|quickfix-window-function| for an explanation
 				of how to write the function and an example.
 		    title	quickfix list title text. See |quickfix-title|
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 71ee94b4e5..6a9e2ed0e8 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -5913,7 +5913,8 @@ A jump table for the options with a short description can be found at |Q_op|.
 	customize the information displayed in the quickfix or location window
 	for each entry in the corresponding quickfix or location list.  See
 	|quickfix-window-function| for an explanation of how to write the
-	function and an example.
+	function and an example. The value can be the name of a function or a
+	lambda.
 
 	This option cannot be set from a |modeline| or in the |sandbox|, for
 	security reasons.
diff --git a/runtime/doc/quickfix.txt b/runtime/doc/quickfix.txt
index 293014b240..4877648730 100644
--- a/runtime/doc/quickfix.txt
+++ b/runtime/doc/quickfix.txt
@@ -1964,7 +1964,10 @@ The function should return a single line of text to display in the quickfix
 window for each entry from start_idx to end_idx. The function can obtain
 information about the entries using the |getqflist()| function and specifying
 the quickfix list identifier "id". For a location list, getloclist() function
-can be used with the 'winid' argument.
+can be used with the 'winid' argument. If an empty list is returned, then the
+default format is used to display all the entries. If an item in the returned
+list is an empty string, then the default format is used to display the
+corresponding entry.
 
 If a quickfix or location list specific customization is needed, then the
 'quickfixtextfunc' attribute of the list can be set using the |setqflist()| or