patch 8.1.1122: char2nr() does not handle composing charactersv8.1.1122

Problem:    char2nr() does not handle composing characters.
Solution:   Add str2list() and list2str(). (Ozaki Kiichi, closes #4190)

2 files changed, 33 insertions, 2 deletions

diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 0b9fb5425..67f548d26 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -2442,6 +2442,7 @@ libcallnr({lib}, {func}, {arg})	Number	idem, but return a Number
 line({expr})			Number	line nr of cursor, last line or mark
 line2byte({lnum})		Number	byte count of line {lnum}
 lispindent({lnum})		Number	Lisp indent for line {lnum}
+list2str({list} [, {utf8}])	String	turn numbers in {list} into a String
 localtime()			Number	current time
 log({expr})			Float	natural logarithm (base e) of {expr}
 log10({expr})			Float	logarithm of Float {expr} to base 10
@@ -2609,6 +2610,8 @@ split({expr} [, {pat} [, {keepempty}]])
 				List	make |List| from {pat} separated {expr}
 sqrt({expr})			Float	square root of {expr}
 str2float({expr})		Float	convert String to Float
+str2list({expr} [, {utf8}])	List	convert each character of {expr} to
+					ASCII/UTF8 value
 str2nr({expr} [, {base}])	Number	convert String to Number
 strchars({expr} [, {skipcc}])	Number	character length of the String {expr}
 strcharpart({str}, {start} [, {len}])
@@ -6193,6 +6196,20 @@ lispindent({lnum})					*lispindent()*
 		When {lnum} is invalid or Vim was not compiled the
 		|+lispindent| feature, -1 is returned.
 
+list2str({list} [, {utf8}])				*list2str()*
+		Convert each number in {list} to a character string can
+		concatenate them all.  Examples: >
+			list2str([32])		returns " "
+			list2str([65, 66, 67])	returns "ABC"
+<		The same can be done (slowly) with: >
+			join(map(list, {nr, val -> nr2char(val)}), '')
+<		|str2list()| does the opposite.
+
+		When {utf8} is omitted or zero, the current 'encoding' is used.
+		With {utf8} is 1, always return utf-8 characters.
+		With utf-8 composing characters work as expected: >
+			list2str([97, 769])	returns "á"
+<
 localtime()						*localtime()*
 		Return the current time, measured as seconds since 1st Jan
 		1970.  See also |strftime()| and |getftime()|.
@@ -8722,6 +8739,18 @@ str2float({expr})					*str2float()*
 			let f = str2float(substitute(text, ',', '', 'g'))
 <		{only available when compiled with the |+float| feature}
 
+str2list({expr} [, {utf8}])				*str2list()*
+		Return a list containing the number values which represent
+		each character in String {expr}.  Examples: >
+			str2list(" ")		returns [32]
+			str2list("ABC")		returns [65, 66, 67]
+<		|list2str()| does the opposite.
+
+		When {utf8} is omitted or zero, the current 'encoding' is used.
+		With {utf8} set to 1, always treat the String as utf-8
+		characters.  With utf-8 composing characters are handled
+		properly: >
+			str2list("á")		returns [97, 769]
 
 str2nr({expr} [, {base}])				*str2nr()*
 		Convert string {expr} to a number.
diff --git a/runtime/doc/usr_41.txt b/runtime/doc/usr_41.txt
index b3b9d3eb9..e8fab8847 100644
--- a/runtime/doc/usr_41.txt
+++ b/runtime/doc/usr_41.txt
@@ -577,8 +577,10 @@ used for.  You can find an alphabetical list here: |functions|.  Use CTRL-] on
 the function name to jump to detailed help on it.
 
 String manipulation:					*string-functions*
-	nr2char()		get a character by its ASCII value
-	char2nr()		get ASCII value of a character
+	nr2char()		get a character by its number value
+	list2str()		get a character string from a list of numbers
+	char2nr()		get number value of a character
+	str2list()		get list of numbers from a string
 	str2nr()		convert a string to a Number
 	str2float()		convert a string to a Float
 	printf()		format a string according to % items