508 lines
12 KiB
V
508 lines
12 KiB
V
/*
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regex 1.0 alpha
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Copyright (c) 2019-2022 Dario Deledda. All rights reserved.
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Use of this source code is governed by an MIT license
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that can be found in the LICENSE file.
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*/
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module regex
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import strings
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/******************************************************************************
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*
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* Inits
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*
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******************************************************************************/
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// regex_base returns a regex object (`RE`) generated from `pattern` string and
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// detailed information in re_err, err_pos, if an error occurred.
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pub fn regex_base(pattern string) (RE, int, int) {
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// init regex
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mut re := RE{}
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re.prog = []Token{len: pattern.len + 1} // max program length, can not be longer then the pattern
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re.cc = []CharClass{len: pattern.len} // can not be more char class the the length of the pattern
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re.group_csave_flag = false // enable continuos group saving
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re.group_max_nested = pattern.len >> 1 // set max 128 group nested
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re.group_max = pattern.len >> 1 // we can't have more groups than the half of the pattern legth
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re.group_stack = []int{len: re.group_max, init: -1}
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re.group_data = []int{len: re.group_max, init: -1}
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re_err, err_pos := re.impl_compile(pattern)
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return re, re_err, err_pos
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}
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/******************************************************************************
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*
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* Utilities
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*
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******************************************************************************/
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// get_group_bounds_by_name get a group boundaries by its name
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pub fn (re RE) get_group_bounds_by_name(group_name string) (int, int) {
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if group_name in re.group_map {
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tmp_index := re.group_map[group_name] - 1
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start := re.groups[tmp_index * 2]
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end := re.groups[tmp_index * 2 + 1]
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return start, end
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}
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return -1, -1
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}
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// get_group_by_name get a group boundaries by its name
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pub fn (re RE) get_group_by_name(in_txt string, group_name string) string {
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if group_name in re.group_map {
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tmp_index := re.group_map[group_name] - 1
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start := re.groups[tmp_index * 2]
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end := re.groups[tmp_index * 2 + 1]
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if start >= 0 && end > start {
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return in_txt[start..end]
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}
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}
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return ''
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}
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// get_group_by_id get a group string by its id
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pub fn (re RE) get_group_by_id(in_txt string, group_id int) string {
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if group_id < (re.groups.len >> 1) {
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index := group_id * 2
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start := re.groups[index]
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end := re.groups[index + 1]
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if start >= 0 && end > start {
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return in_txt[start..end]
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}
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}
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return ''
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}
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// get_group_by_id get a group boundaries by its id
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pub fn (re RE) get_group_bounds_by_id(group_id int) (int, int) {
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if group_id < re.group_count {
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index := group_id * 2
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return re.groups[index], re.groups[index + 1]
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}
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return -1, -1
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}
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pub struct Re_group {
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pub:
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start int = -1
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end int = -1
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}
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// get_group_list return a list of Re_group for the found groups
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pub fn (re RE) get_group_list() []Re_group {
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mut res := []Re_group{len: re.groups.len >> 1}
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mut gi := 0
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// println("len: ${re.groups.len} groups: ${re.groups}")
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for gi < re.groups.len {
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if re.groups[gi] >= 0 {
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txt_st := re.groups[gi]
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txt_en := re.groups[gi + 1]
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// println("#${gi/2} start: ${re.groups[gi]} end: ${re.groups[gi + 1]} ")
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if txt_st >= 0 && txt_en > txt_st {
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tmp := Re_group{
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start: re.groups[gi]
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end: re.groups[gi + 1]
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}
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// println(tmp)
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res[gi >> 1] = tmp
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} else {
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res[gi >> 1] = Re_group{}
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}
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}
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gi += 2
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}
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return res
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}
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/******************************************************************************
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*
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* Matchers
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*
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******************************************************************************/
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// match_string Match the pattern with the in_txt string
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[direct_array_access]
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pub fn (mut re RE) match_string(in_txt string) (int, int) {
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start, mut end := re.match_base(in_txt.str, in_txt.len + 1)
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if end > in_txt.len {
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end = in_txt.len
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}
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if start >= 0 && end > start {
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if (re.flag & f_ms) != 0 && start > 0 {
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return no_match_found, 0
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}
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if (re.flag & f_me) != 0 && end < in_txt.len {
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if in_txt[end] in new_line_list {
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return start, end
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}
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return no_match_found, 0
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}
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return start, end
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}
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return start, end
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}
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// matches_string Checks if the pattern matches the in_txt string
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pub fn (mut re RE) matches_string(in_txt string) bool {
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start, _ := re.match_string(in_txt)
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return start != no_match_found
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}
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/******************************************************************************
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*
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* Finders
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*
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******************************************************************************/
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/*
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// find internal implementation HERE for reference do not remove!!
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[direct_array_access]
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fn (mut re RE) find_imp(in_txt string) (int,int) {
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old_flag := re.flag
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re.flag |= f_src // enable search mode
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start, mut end := re.match_base(in_txt.str, in_txt.len + 1)
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//print("Find [$start,$end] '${in_txt[start..end]}'")
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if end > in_txt.len {
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end = in_txt.len
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}
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re.flag = old_flag
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if start >= 0 && end > start {
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return start, end
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}
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return no_match_found, 0
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}
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*/
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// find try to find the first match in the input string
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[direct_array_access]
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pub fn (mut re RE) find(in_txt string) (int, int) {
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// old_flag := re.flag
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// re.flag |= f_src // enable search mode
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mut i := 0
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for i < in_txt.len {
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mut s := -1
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mut e := -1
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unsafe {
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// tmp_str := tos(in_txt.str + i, in_txt.len - i)
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// println("Check: [$tmp_str]")
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s, e = re.match_base(in_txt.str + i, in_txt.len - i + 1)
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if s >= 0 && e > s {
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// println("find match in: ${i+s},${i+e} [${in_txt[i+s..i+e]}]")
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// re.flag = old_flag
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mut gi := 0
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for gi < re.groups.len {
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re.groups[gi] += i
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gi++
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}
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return i + s, i + e
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}
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i++
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}
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}
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// re.flag = old_flag
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return -1, -1
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}
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// find try to find the first match in the input string strarting from start index
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[direct_array_access]
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pub fn (mut re RE) find_from(in_txt string, start int) (int, int) {
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old_flag := re.flag
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// re.flag |= f_src // enable search mode
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mut i := start
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if i < 0 {
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return -1, -1
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}
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for i < in_txt.len {
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//--- speed references ---
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mut s := -1
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mut e := -1
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unsafe {
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tmp_str := tos(in_txt.str + i, in_txt.len - i)
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s, e = re.match_string(tmp_str)
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}
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//------------------------
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// s,e = re.find_imp(in_txt[i..])
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//------------------------
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if s >= 0 && e > s {
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// println("find match in: ${i+s},${i+e} [${in_txt[i+s..i+e]}]")
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re.flag = old_flag
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mut gi := 0
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for gi < re.groups.len {
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re.groups[gi] += i
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gi++
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}
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return i + s, i + e
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} else {
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i++
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}
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}
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re.flag = old_flag
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return -1, -1
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}
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// find_all find all the non overlapping occurrences of the match pattern and return the start and end index of the match
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//
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// Usage:
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// ```v
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// blurb := 'foobar boo steelbar toolbox foot tooooot'
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// mut re := regex.regex_opt('f|t[eo]+')?
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// res := re.find_all(blurb) // [0, 3, 12, 15, 20, 23, 28, 31, 33, 39]
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// ```
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[direct_array_access]
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pub fn (mut re RE) find_all(in_txt string) []int {
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// old_flag := re.flag
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// re.flag |= f_src // enable search mode
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mut i := 0
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mut res := []int{}
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for i < in_txt.len {
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mut s := -1
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mut e := -1
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unsafe {
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// tmp_str := in_txt[i..]
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// tmp_str := tos(in_txt.str + i, in_txt.len - i)
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// println("Check: [$tmp_str]")
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s, e = re.match_base(in_txt.str + i, in_txt.len + 1 - i)
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if s >= 0 && e > s {
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res << i + s
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res << i + e
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i += e
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continue
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}
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/*
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if e > 0 {
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i += e
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continue
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}
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*/
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i++
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}
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}
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// re.flag = old_flag
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return res
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}
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// find_all_str find all the non overlapping occurrences of the match pattern, return a string list
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[direct_array_access]
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pub fn (mut re RE) find_all_str(in_txt string) []string {
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// old_flag := re.flag
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// re.flag |= f_src // enable search mode
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mut i := 0
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mut res := []string{}
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for i < in_txt.len {
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mut s := -1
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mut e := -1
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unsafe {
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// tmp_str := in_txt[i..]
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// tmp_str := tos(in_txt.str + i, in_txt.len - i)
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// println("Check: [$tmp_str]")
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s, e = re.match_base(in_txt.str + i, in_txt.len + 1 - i)
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if s >= 0 && e > s {
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tmp_str := tos(in_txt.str + i, in_txt.len - i)
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mut tmp_e := if e > tmp_str.len { tmp_str.len } else { e }
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// println("Found: $s:$e [${tmp_str[s..e]}]")
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res << tmp_str[..tmp_e]
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i += e
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continue
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}
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}
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/*
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if e > 0 {
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i += e
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continue
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}
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*/
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i++
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}
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// re.flag = old_flag
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return res
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}
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/******************************************************************************
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*
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* Replacers
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*
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******************************************************************************/
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// replace_simple return a string where the matches are replaced with the replace string
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pub fn (mut re RE) replace_simple(in_txt string, repl string) string {
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pos := re.find_all(in_txt)
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if pos.len > 0 {
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mut res := ''
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mut i := 0
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mut s1 := 0
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mut e1 := in_txt.len
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for i < pos.len {
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e1 = pos[i]
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res += in_txt[s1..e1] + repl
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s1 = pos[i + 1]
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i += 2
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}
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res += in_txt[s1..]
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return res
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}
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return in_txt
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}
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// type of function used for custom replace
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// in_txt source text
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// start index of the start of the match in in_txt
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// end index of the end of the match in in_txt
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// the match is in in_txt[start..end]
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pub type FnReplace = fn (re RE, in_txt string, start int, end int) string
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// replace_by_fn return a string where the matches are replaced with the string from the repl_fn callback function
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pub fn (mut re RE) replace_by_fn(in_txt string, repl_fn FnReplace) string {
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mut i := 0
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mut res := strings.new_builder(in_txt.len)
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mut last_end := 0
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for i < in_txt.len {
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// println("Find Start. $i [${in_txt[i..]}]")
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s, e := re.find_from(in_txt, i)
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// println("Find End.")
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if s >= 0 && e > s {
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// println("find match in: ${s},${e} [${in_txt[s..e]}]")
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if last_end < s {
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res.write_string(in_txt[last_end..s])
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}
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/*
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for g_i in 0 .. re.group_count {
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re.groups[g_i * 2] += i
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re.groups[(g_i * 2) + 1] += i
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}
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*/
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repl := repl_fn(re, in_txt, s, e)
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// println("repl res: $repl")
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res.write_string(repl)
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// res.write_string("[[${in_txt[s..e]}]]")
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last_end = e
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i = e
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} else {
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break
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// i++
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}
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// println(i)
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}
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if last_end >= 0 && last_end < in_txt.len {
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res.write_string(in_txt[last_end..])
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}
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return res.str()
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}
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fn (re RE) parsed_replace_string(in_txt string, repl string) string {
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str_lst := repl.split('\\')
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mut res := str_lst[0]
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mut i := 1
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for i < str_lst.len {
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tmp := str_lst[i]
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// println("tmp: ${tmp}")
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if tmp.len > 0 && tmp[0] >= `0` && tmp[0] <= `9` {
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group_id := int(tmp[0] - `0`)
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group := re.get_group_by_id(in_txt, group_id)
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// println("group: $group_id [$group]")
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res += '$group${tmp[1..]}'
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} else {
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res += '\\' + tmp
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}
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i++
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}
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return res
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}
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// replace return a string where the matches are replaced with the repl_str string,
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// this function support use groups in the replace string
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pub fn (mut re RE) replace(in_txt string, repl_str string) string {
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mut i := 0
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mut res := strings.new_builder(in_txt.len)
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mut last_end := 0
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for i < in_txt.len {
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// println("Find Start. $i [${in_txt[i..]}]")
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s, e := re.find_from(in_txt, i)
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// println("Find End.")
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if s >= 0 && e > s {
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// println("find match in: ${s},${e} [${in_txt[s..e]}]")
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if last_end < s {
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res.write_string(in_txt[last_end..s])
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}
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/*
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for g_i in 0 .. re.group_count {
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re.groups[g_i * 2] += i
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re.groups[(g_i * 2) + 1] += i
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}
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*/
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// repl := repl_fn(re, in_txt, s, e)
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repl := re.parsed_replace_string(in_txt, repl_str)
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// println("repl res: $repl")
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res.write_string(repl)
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// res.write_string("[[${in_txt[s..e]}]]")
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last_end = e
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i = e
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} else {
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break
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// i++
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}
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// println(i)
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}
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if last_end >= 0 && last_end < in_txt.len {
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res.write_string(in_txt[last_end..])
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}
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return res.str()
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}
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// replace_n return a string where the firts count matches are replaced with the repl_str string,
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// if count is > 0 the replace began from the start of the string toward the end
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// if count is < 0 the replace began from the end of the string toward the start
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// if count is 0 do nothing
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pub fn (mut re RE) replace_n(in_txt string, repl_str string, count int) string {
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mut i := 0
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mut index := 0
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mut i_p := 0
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mut res := strings.new_builder(in_txt.len)
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mut lst := re.find_all(in_txt)
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if count < 0 { // start from the right of the string
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lst = lst#[count * 2..] // limitate the number of substitions
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} else if count > 0 { // start from the left of the string
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lst = lst#[..count * 2] // limitate the number of substitions
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} else if count == 0 { // no replace
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return in_txt
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}
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// println("found: ${lst}")
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for index < lst.len {
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i = lst[index]
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res.write_string(in_txt[i_p..i])
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res.write_string(repl_str)
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index++
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i_p = lst[index]
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index++
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}
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i = i_p
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res.write_string(in_txt[i..])
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return res.str()
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}
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