builtin: deprecate string.last_index/1 for string.index_last/1, and string.last_index_u8/1 for string.index_u8_last/1 (#20095)

examples/sokol/06_obj_viewer/modules/obj/obj.v

@@ -232,7 +232,7 @@ pub fn (mut obj_part ObjPart) parse_obj_buffer(rows []string, single_material bo
 							mat_count++
 							mut part := Part{}
 							if mat_count > 1 {
-								li := obj_part.part[obj_part.part.len - 1].name.last_index('_m') or {
+								li := obj_part.part[obj_part.part.len - 1].name.index_last('_m') or {
 									obj_part.part[obj_part.part.len - 1].name.len - 1
 								}
 								part.name = obj_part.part[obj_part.part.len - 1].name[..li] +

vlib/builtin/js/string.js.v

@@ -730,7 +730,7 @@ pub fn (s string) replace_each(vals []string) string {
 }
 
 // last_index returns the position of the last occurrence of the input string.
-fn (s string) last_index_(p string) int {
+fn (s string) index_last_(p string) int {
 	if p.len > s.len || p.len == 0 {
 		return -1
 	}
@@ -748,15 +748,23 @@ fn (s string) last_index_(p string) int {
 	return -1
 }
 
-// last_index returns the position of the last occurrence of the input string.
-pub fn (s string) last_index(p string) ?int {
-	idx := s.last_index_(p)
+// index_last returns the position of the first character of the *last* occurance of the `needle` string in `s`.
+pub fn (s string) index_last(needle string) ?int {
+	idx := s.index_last_(needle)
 	if idx == -1 {
 		return none
 	}
 	return idx
 }
 
+// last_index returns the position of the first character of the *last* occurance of the `needle` string in `s`.
+@[deprecated: 'use `.index_last(needle string)` instead']
+@[deprecated_after: '2023-12-18']
+@[inline]
+pub fn (s string) last_index(needle string) ?int {
+	return s.index_last(needle)
+}
+
 pub fn (s string) trim_space() string {
 	res := ''
 	#res.str = s.str.trim()
@@ -969,6 +977,27 @@ pub fn (s string) index(search string) ?int {
 	return res
 }
 
+// index_u8_last returns the index of the *last* occurrence of the byte `c` (if found) in the string.
+// It returns -1, if `c` is not found.
+@[direct_array_access]
+pub fn (s string) index_u8_last(c u8) int {
+	for i := s.len - 1; i >= 0; i-- {
+		if s[i] == c {
+			return i
+		}
+	}
+	return -1
+}
+
+// last_index_u8 returns the index of the last occurrence of byte `c` if found in the string.
+// It returns -1, if the byte `c` is not found.
+@[deprecated: 'use `.index_u8_last(c u8)` instead']
+@[deprecated_after: '2023-12-18']
+@[inline]
+pub fn (s string) last_index_u8(c u8) int {
+	return s.index_u8_last(c)
+}
+
 pub fn (_rune string) utf32_code() int {
 	res := 0
 	#res.val = s.str.charCodeAt()

vlib/builtin/string.v

@@ -1152,8 +1152,8 @@ fn (s string) index_(p string) int {
 	return -1
 }
 
-// index returns the position of the first character of the input string.
-// It will return `none` if the input string can't be found.
+// index returns the position of the first character of the first occurance of the `needle` string in `s`.
+// It will return `none` if the `needle` string can't be found in `s`.
 pub fn (s string) index(p string) ?int {
 	idx := s.index_(p)
 	if idx == -1 {
@@ -1162,6 +1162,23 @@ pub fn (s string) index(p string) ?int {
 	return idx
 }
 
+// index_last returns the position of the first character of the *last* occurance of the `needle` string in `s`.
+pub fn (s string) index_last(needle string) ?int {
+	idx := s.index_last_(needle)
+	if idx == -1 {
+		return none
+	}
+	return idx
+}
+
+// last_index returns the position of the first character of the *last* occurance of the `needle` string in `s`.
+@[deprecated: 'use `.index_last(needle string)` instead']
+@[deprecated_after: '2023-12-18']
+@[inline]
+pub fn (s string) last_index(needle string) ?int {
+	return s.index_last(needle)
+}
+
 // index_kmp does KMP search.
 @[direct_array_access; manualfree]
 fn (s string) index_kmp(p string) int {
@@ -1209,9 +1226,9 @@ pub fn (s string) index_any(chars string) int {
 	return -1
 }
 
-// last_index returns the position of the last occurrence of the input string.
+// index_last_ returns the position of the last occurrence of the given string `p` in `s`.
 @[direct_array_access]
-fn (s string) last_index_(p string) int {
+fn (s string) index_last_(p string) int {
 	if p.len > s.len || p.len == 0 {
 		return -1
 	}
@@ -1229,15 +1246,6 @@ fn (s string) last_index_(p string) int {
 	return -1
 }
 
-// last_index returns the position of the last occurrence of the input string.
-pub fn (s string) last_index(p string) ?int {
-	idx := s.last_index_(p)
-	if idx == -1 {
-		return none
-	}
-	return idx
-}
-
 // index_after returns the position of the input string, starting search from `start` position.
 @[direct_array_access]
 pub fn (s string) index_after(p string, start int) int {
@@ -1279,10 +1287,10 @@ pub fn (s string) index_u8(c u8) int {
 	return -1
 }
 
-// last_index_byte returns the index of the last occurrence of byte `c` if found in the string.
-// last_index_byte returns -1 if the byte is not found.
+// index_u8_last returns the index of the *last* occurrence of the byte `c` (if found) in the string.
+// It returns -1, if `c` is not found.
 @[direct_array_access]
-pub fn (s string) last_index_u8(c u8) int {
+pub fn (s string) index_u8_last(c u8) int {
 	for i := s.len - 1; i >= 0; i-- {
 		if unsafe { s.str[i] == c } {
 			return i
@@ -1291,6 +1299,15 @@ pub fn (s string) last_index_u8(c u8) int {
 	return -1
 }
 
+// last_index_u8 returns the index of the last occurrence of byte `c` if found in the string.
+// It returns -1, if the byte `c` is not found.
+@[deprecated: 'use `.index_u8_last(c u8)` instead']
+@[deprecated_after: '2023-12-18']
+@[inline]
+pub fn (s string) last_index_u8(c u8) int {
+	return s.index_u8_last(c)
+}
+
 // count returns the number of occurrences of `substr` in the string.
 // count returns -1 if no `substr` could be found.
 @[direct_array_access]
@@ -1879,7 +1896,7 @@ pub fn (s string) all_before(sub string) string {
 // Example: assert '23:34:45.234'.all_before_last(':') == '23:34'
 // Example: assert 'abcd'.all_before_last('.') == 'abcd'
 pub fn (s string) all_before_last(sub string) string {
-	pos := s.last_index_(sub)
+	pos := s.index_last_(sub)
 	if pos == -1 {
 		return s.clone()
 	}
@@ -1903,7 +1920,7 @@ pub fn (s string) all_after(sub string) string {
 // Example: assert '23:34:45.234'.all_after_last(':') == '45.234'
 // Example: assert 'abcd'.all_after_last('z') == 'abcd'
 pub fn (s string) all_after_last(sub string) string {
-	pos := s.last_index_(sub)
+	pos := s.index_last_(sub)
 	if pos == -1 {
 		return s.clone()
 	}

vlib/builtin/string_test.v

@@ -1233,11 +1233,21 @@ fn test_index_u8() {
 	//
 }
 
-fn test_last_index_u8() {
-	assert 'abcabca'.last_index_u8(`a`) == 6
-	assert 'abcabca'.last_index_u8(`c`) == 5
-	assert 'abcabca'.last_index_u8(`b`) == 4
-	assert 'Zabcabca'.last_index_u8(`Z`) == 0
+fn test_index_last() {
+	assert 'abcabca'.index_last('ca')? == 5
+	assert 'abcabca'.index_last('ab')? == 3
+	assert 'abcabca'.index_last('b')? == 4
+	assert 'Zabcabca'.index_last('Z')? == 0
+	x := 'Zabcabca'.index_last('Y')
+	assert x == none
+	// TODO: `assert 'Zabcabca'.index_last('Y') == none` is a cgen error, 2023/12/04
+}
+
+fn test_index_u8_last() {
+	assert 'abcabca'.index_u8_last(`a`) == 6
+	assert 'abcabca'.index_u8_last(`c`) == 5
+	assert 'abcabca'.index_u8_last(`b`) == 4
+	assert 'Zabcabca'.index_u8_last(`Z`) == 0
 	//
 	assert 'abc'.index_u8(`d`) == -1
 	assert 'abc'.index_u8(`A`) == -1

vlib/io/util/util.v

@@ -79,7 +79,7 @@ fn prefix_and_suffix(pattern string) !(string, string) {
 	if pat.contains(os.path_separator) {
 		return error('pattern cannot contain path separators (${os.path_separator}).')
 	}
-	pos := pat.last_index('*') or { -1 }
+	pos := pat.index_u8_last(`*`)
 	mut prefix := ''
 	mut suffix := ''
 	if pos != -1 {

vlib/net/urllib/urllib.v

@@ -533,7 +533,7 @@ struct ParseAuthorityRes {
 }
 
 fn parse_authority(authority string) !ParseAuthorityRes {
-	i := authority.last_index('@') or { -1 }
+	i := authority.index_u8_last(`@`)
 	mut host := ''
 	mut zuser := user('')
 	if i < 0 {
@@ -574,10 +574,11 @@ fn parse_authority(authority string) !ParseAuthorityRes {
 // parse_host parses host as an authority without user
 // information. That is, as host[:port].
 fn parse_host(host string) !string {
-	if host.starts_with('[') {
+	if host.len > 0 && host[0] == `[` {
 		// parse an IP-Literal in RFC 3986 and RFC 6874.
 		// E.g., '[fe80::1]', '[fe80::1%25en0]', '[fe80::1]:80'.
-		mut i := host.last_index(']') or {
+		mut i := host.index_u8_last(`]`)
+		if i == -1 {
 			return error(error_msg("parse_host: missing ']' in host", ''))
 		}
 		mut colon_port := host[i + 1..]
@@ -597,11 +598,14 @@ fn parse_host(host string) !string {
 			host3 := unescape(host[i..], .encode_host) or { return err.msg() }
 			return host1 + host2 + host3
 		}
-	} else if i := host.last_index(':') {
-		colon_port := host[i..]
-		if !valid_optional_port(colon_port) {
-			return error(error_msg('parse_host: invalid port ${colon_port} after host ',
-				''))
+	} else {
+		i := host.index_u8_last(`:`)
+		if i != -1 {
+			colon_port := host[i..]
+			if !valid_optional_port(colon_port) {
+				return error(error_msg('parse_host: invalid port ${colon_port} after host ',
+					''))
+			}
 		}
 	}
 	h := unescape(host, .encode_host) or { return err.msg() }
@@ -870,7 +874,7 @@ fn resolve_path(base string, ref string) string {
 	if ref == '' {
 		full = base
 	} else if ref[0] != `/` {
-		i := base.last_index('/') or { -1 }
+		i := base.index_u8_last(`/`)
 		full = base[..i + 1] + ref
 	} else {
 		full = ref
@@ -1004,14 +1008,14 @@ pub fn (u &URL) port() string {
 pub fn split_host_port(hostport string) (string, string) {
 	mut host := hostport
 	mut port := ''
-	colon := host.last_index_u8(`:`)
+	colon := host.index_u8_last(`:`)
 	if colon != -1 {
 		if valid_optional_port(host[colon..]) {
 			port = host[colon + 1..]
 			host = host[..colon]
 		}
 	}
-	if host.starts_with('[') && host.ends_with(']') {
+	if host.len > 1 && host[0] == `[` && host.ends_with(']') {
 		host = host[1..host.len - 1]
 	}
 	return host, port

vlib/os/os.v

@@ -237,12 +237,15 @@ pub fn is_dir_empty(path string) bool {
 // ```
 pub fn file_ext(opath string) string {
 	if opath.len < 3 {
-		return empty_str
+		return ''
 	}
 	path := file_name(opath)
-	pos := path.last_index(dot_str) or { return empty_str }
+	pos := path.index_u8_last(`.`)
+	if pos == -1 {
+		return ''
+	}
 	if pos + 1 >= path.len || pos == 0 {
-		return empty_str
+		return ''
 	}
 	return path[pos..]
 }
@@ -258,7 +261,7 @@ pub fn dir(opath string) string {
 	}
 	other_separator := if path_separator == '/' { '\\' } else { '/' }
 	path := opath.replace(other_separator, path_separator)
-	pos := path.last_index(path_separator) or { return '.' }
+	pos := path.index_last(path_separator) or { return '.' }
 	if pos == 0 && path_separator == '/' {
 		return '/'
 	}
@@ -280,10 +283,10 @@ pub fn base(opath string) string {
 	}
 	if path.ends_with(path_separator) {
 		path2 := path[..path.len - 1]
-		pos := path2.last_index(path_separator) or { return path2.clone() }
+		pos := path2.index_last(path_separator) or { return path2.clone() }
 		return path2[pos + 1..]
 	}
-	pos := path.last_index(path_separator) or { return path.clone() }
+	pos := path.index_last(path_separator) or { return path.clone() }
 	return path[pos + 1..]
 }
 

vlib/semver/parse.v

@@ -19,7 +19,7 @@ fn parse(input string) RawVersion {
 	mut raw_version := input
 	mut prerelease := ''
 	mut metadata := ''
-	plus_idx := raw_version.last_index('+') or { -1 }
+	plus_idx := raw_version.index_u8_last(`+`)
 	if plus_idx > 0 {
 		metadata = raw_version[(plus_idx + 1)..]
 		raw_version = raw_version[0..plus_idx]

vlib/v/checker/checker.v

@@ -480,7 +480,7 @@ fn (mut c Checker) check_valid_snake_case(name string, identifier string, pos to
 }
 
 fn stripped_name(name string) string {
-	idx := name.last_index('.') or { -1 }
+	idx := name.index_last('.') or { -1 }
 	return name[(idx + 1)..]
 }
 

vlib/v/checker/struct.v

@@ -489,7 +489,7 @@ fn (mut c Checker) struct_init(mut node ast.StructInit, is_field_zero_struct_ini
 	// but `x := T{}` is ok.
 	if !c.is_builtin_mod && !c.inside_unsafe && type_sym.language == .v
 		&& c.table.cur_concrete_types.len == 0 {
-		pos := type_sym.name.last_index('.') or { -1 }
+		pos := type_sym.name.index_u8_last(`.`)
 		first_letter := type_sym.name[pos + 1]
 		if !first_letter.is_capital()
 			&& (type_sym.kind != .struct_ || !(type_sym.info as ast.Struct).is_anon)

vlib/v/checker/tests/type_cast_option_err.out

@@ -1,5 +1,5 @@
 vlib/v/checker/tests/type_cast_option_err.vv:2:10: error: cannot type cast an Option
     1 | fn main() {
-    2 |     println(int('hi'.last_index('i')))
+    2 |     println(int('hi'.index_last('i')))
       |             ~~~~~~~~~~~~~~~~~~~~~~~~~
     3 | }

vlib/v/checker/tests/type_cast_option_err.vv

@@ -1,3 +1,3 @@
 fn main() {
-	println(int('hi'.last_index('i')))
+	println(int('hi'.index_last('i')))
 }

vlib/v/gen/js/js.v

@@ -306,10 +306,10 @@ pub fn gen(files []&ast.File, table &ast.Table, pref_ &pref.Preferences) string
 				// calculate final generated location in output based on position
 				current_segment := g.out.substr(int(sm_pos), int(sourcemap_ns_entry.ns_pos))
 				current_line += u32(current_segment.count('\n'))
-				current_column := if last_nl_pos := current_segment.last_index('\n') {
-					u32(current_segment.len - last_nl_pos - 1)
-				} else {
-					u32(0)
+				mut current_column := u32(0)
+				last_nl_pos := current_segment.index_u8_last(`\n`)
+				if last_nl_pos != -1 {
+					current_column = u32(current_segment.len - last_nl_pos - 1)
 				}
 				g.sourcemap.add_mapping(sourcemap_ns_entry.src_path, sourcemap.SourcePosition{
 					source_line: sourcemap_ns_entry.src_line
@@ -541,7 +541,10 @@ pub fn (mut g JsGen) new_tmp_var() string {
 // 'fn' => ''
 @[inline]
 fn get_ns(s string) string {
-	idx := s.last_index('.') or { return '' }
+	idx := s.index_u8_last(`.`)
+	if idx == -1 {
+		return ''
+	}
 	return s.substr(0, idx)
 }
 

vlib/v/tests/option_default_values_test.v

@@ -127,7 +127,7 @@ fn test_nested_option_with_opt_fn_call_as_last_value() {
 
 fn remove_suffix1(s string) string {
 	n := s.len
-	i := s.last_index('.') or { n }
+	i := s.index_last('.') or { n }
 	return s[0..i]
 }