builtin: add s.trim_space_left/0 and s.trim_space_right/0 methods (#2…

…1903)

vlib/builtin/string.v

@@ -1690,6 +1690,20 @@ pub fn (s string) trim_space() string {
 	return s.trim(' \n\t\v\f\r')
 }
 
+// trim_space_left strips any of ` `, `\n`, `\t`, `\v`, `\f`, `\r` from the start of the string.
+// Example: assert ' Hello V '.trim_space_left() == 'Hello V '
+@[inline]
+pub fn (s string) trim_space_left() string {
+	return s.trim_left(' \n\t\v\f\r')
+}
+
+// trim_space_right strips any of ` `, `\n`, `\t`, `\v`, `\f`, `\r` from the end of the string.
+// Example: assert ' Hello V '.trim_space_right() == ' Hello V'
+@[inline]
+pub fn (s string) trim_space_right() string {
+	return s.trim_right(' \n\t\v\f\r')
+}
+
 // trim strips any of the characters given in `cutset` from the start and end of the string.
 // Example: assert ' ffHello V ffff'.trim(' f') == 'Hello V'
 pub fn (s string) trim(cutset string) string {

vlib/builtin/string_test.v

@@ -596,6 +596,9 @@ fn test_is_int() {
 fn test_trim_space() {
 	a := ' a '
 	assert a.trim_space() == 'a'
+	assert a.trim_space_left() == 'a '
+	assert a.trim_space_right() == ' a'
+
 	code := '
 
 fn main() {
@@ -606,7 +609,19 @@ fn main() {
 	code_clean := 'fn main() {
         println(2)
 }'
+	code_trim_right := '
+
+fn main() {
+        println(2)
+}'
+	code_trim_left := 'fn main() {
+        println(2)
+}
+
+'
 	assert code.trim_space() == code_clean
+	assert code.trim_space_right() == code_trim_right
+	assert code.trim_space_left() == code_trim_left
 }
 
 fn test_join() {

vlib/flag/flag_to.v

@@ -737,13 +737,13 @@ pub fn (fm FlagMapper) fields_docs(dc DocConfig) ![]string {
 			diff := -flag_line_diff
 			line := flag_line + ' '.repeat(diff) +
 				keep_at_max(doc, desc_max).replace('\n', '\n${empty_padding}')
-			docs << line.trim_right(' \n\t\v\f\r')
+			docs << line.trim_space_right()
 		} else {
-			docs << flag_line.trim_right(' \n\t\v\f\r')
+			docs << flag_line.trim_space_right()
 			if doc != '' {
 				line := empty_padding +
 					keep_at_max(doc, desc_max).replace('\n', '\n${empty_padding}')
-				docs << line.trim_right(' \n\t\v\f\r')
+				docs << line.trim_space_right()
 			}
 		}
 		if !dc.options.compact {
@@ -760,12 +760,12 @@ pub fn (fm FlagMapper) fields_docs(dc DocConfig) ![]string {
 				diff := -flag_line_diff
 				line := indent_flags_padding + entry.trim(' ') + ' '.repeat(diff) +
 					keep_at_max(doc, desc_max).replace('\n', '\n${empty_padding}')
-				docs << line.trim_right(' \n\t\v\f\r')
+				docs << line.trim_space_right()
 			} else {
 				docs << indent_flags_padding + entry.trim(' ')
 				line := empty_padding +
 					keep_at_max(doc, desc_max).replace('\n', '\n${empty_padding}')
-				docs << line.trim_right(' \n\t\v\f\r')
+				docs << line.trim_space_right()
 			}
 			if !dc.options.compact {
 				docs << ''