patch 9.1.1669: Vim script: no support for URI de-/encoding

Problem:  Vim script: no support for URI de-/encoding
          (ubaldot)
Solution: Add the uri_encode() and uri_decode() functions
          (Yegappan Lakshmanan)

fixes: #17861
closes: #18034

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/builtin.txt

@@ -747,6 +747,8 @@ undofile({name})		String	undo file name for {name}
 undotree([{buf}])		List	undo file tree for buffer {buf}
 uniq({list} [, {func} [, {dict}]])
 				List	remove adjacent duplicates from a list
+uri_decode({string})		String	URI-decode a string
+uri_encode({string})		String	URI-encode a string
 utf16idx({string}, {idx} [, {countcc} [, {charidx}]])
 				Number	UTF-16 index of byte {idx} in {string}
 values({dict})			List	values in {dict}
@@ -12187,6 +12189,59 @@ uniq({list} [, {func} [, {dict}]])			*uniq()* *E882*
 		Return type: list<{type}>
 
 
+uri_decode({string})					*uri_decode()*
+		Returns the URI-decoded form of {string}, reversing
+		percent-encoding (converting sequences like "%3D" back to
+		the corresponding character).
+
+		The decoding follows standard percent-decoding rules:
+		    - "%HH" is replaced with the character for the hex value
+		      HH.
+		    - If the decoded bytes form valid UTF-8, they are combined
+		      into the corresponding character(s).  Otherwise, the
+		      bytes are kept as-is.
+		    - Invalid or incomplete encodings (e.g. "%GZ", "%3", or a
+		      trailing "%") are left unchanged.
+
+		Returns an empty String if {string} is empty.
+
+		Example: >
+			:echo uri_decode('c%3A%5Cmy%5Cdir%5Cfoo%20bar')
+			c:\my\dir\foo bar
+			:echo uri_decode('%CE%B1%CE%B2%CE%B3')
+			αβγ
+<
+		Can also be used as a |method|: >
+			mystr->uri_decode()
+<
+		Return type: |String|
+
+uri_encode({string})					*uri_encode()*
+		Returns the URI-encoded form of {string}.  URI encoding
+		replaces unsafe or reserved characters with percent-encoded
+		sequences.
+
+		The encoding follows standard percent-encoding rules:
+                    - Alphanumeric characters [0-9A-Za-z] remain unchanged.
+                    - The characters "-", "_", ".", and "~" also remain
+                      unchanged.
+                    - All other characters are replaced with "%HH", where HH
+                      is the two-digit uppercase hexadecimal value.
+                    - Existing percent-encoded sequences are not modified.
+
+		Returns an empty String if {string} is empty.
+
+		Example: >
+			:echo uri_encode('c:\my\dir\foo bar')
+			c%3A%5Cmy%5Cdir%5Cfoo%20bar
+			:echo uri_encode('key=value&name=αβγ')
+			key%3Dvalue%26name%3D%CE%B1%CE%B2%CE%B3
+<
+		Can also be used as a |method|: >
+			mystr->uri_encode()
+<
+		Return type: |String|
+
 							*utf16idx()*
 utf16idx({string}, {idx} [, {countcc} [, {charidx}]])
 		Same as |charidx()| but returns the UTF-16 code unit index of

runtime/doc/tags

@@ -11101,6 +11101,8 @@ unix	os_unix.txt	/*unix*
 unlisted-buffer	windows.txt	/*unlisted-buffer*
 up-down-motions	motion.txt	/*up-down-motions*
 uppercase	change.txt	/*uppercase*
+uri_decode()	builtin.txt	/*uri_decode()*
+uri_encode()	builtin.txt	/*uri_encode()*
 urxvt-mouse	options.txt	/*urxvt-mouse*
 use-visual-cmds	version4.txt	/*use-visual-cmds*
 useful-mappings	tips.txt	/*useful-mappings*

runtime/doc/usr_41.txt

@@ -807,6 +807,8 @@ String manipulation:					*string-functions*
 	str2blob()		convert a list of strings into a blob
 	blob2str()		convert a blob into a list of strings
 	items()			get List of String index-character pairs
+	uri_encode()		URI-encode a string
+	uri_decode()		URI-decode a string
 
 List manipulation:					*list-functions*
 	get()			get an item without error for wrong index

runtime/doc/version9.txt

@@ -41788,6 +41788,8 @@ Functions: ~
 |str2blob()|		convert a List of strings into a blob
 |test_null_tuple()|	return a null tuple
 |tuple2list()|		turn a Tuple of items into a List
+|uri_decode()|		URI-decode a string
+|uri_encode()|		URI-encode a string
 |wildtrigger()|		trigger wildcard expansion