505 lines
13 KiB
Rust
505 lines
13 KiB
Rust
use self::SeparatorCategory::*;
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use deunicode::deunicode_char;
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use slice_group_by::StrGroupBy;
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use std::iter::Peekable;
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pub fn is_cjk(c: char) -> bool {
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(c >= '\u{2e80}' && c <= '\u{2eff}')
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|| (c >= '\u{2f00}' && c <= '\u{2fdf}')
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|| (c >= '\u{3040}' && c <= '\u{309f}')
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|| (c >= '\u{30a0}' && c <= '\u{30ff}')
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|| (c >= '\u{3100}' && c <= '\u{312f}')
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|| (c >= '\u{3200}' && c <= '\u{32ff}')
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|| (c >= '\u{3400}' && c <= '\u{4dbf}')
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|| (c >= '\u{4e00}' && c <= '\u{9fff}')
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|| (c >= '\u{f900}' && c <= '\u{faff}')
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}
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#[derive(Debug, Copy, Clone, PartialEq, Eq)]
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enum SeparatorCategory {
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Soft,
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Hard,
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}
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impl SeparatorCategory {
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fn merge(self, other: SeparatorCategory) -> SeparatorCategory {
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if let (Soft, Soft) = (self, other) {
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Soft
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} else {
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Hard
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}
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}
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fn to_usize(self) -> usize {
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match self {
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Soft => 1,
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Hard => 8,
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}
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}
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}
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fn is_separator(c: char) -> bool {
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classify_separator(c).is_some()
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}
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fn classify_separator(c: char) -> Option<SeparatorCategory> {
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match c {
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c if c.is_whitespace() => Some(Soft), // whitespaces
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c if deunicode_char(c) == Some("'") => Some(Soft), // quotes
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c if deunicode_char(c) == Some("\"") => Some(Soft), // double quotes
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'-' | '_' | '\'' | ':' | '/' | '\\' => Some(Soft),
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'.' | ';' | ',' | '!' | '?' | '(' | ')' => Some(Hard),
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_ => None,
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}
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}
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#[derive(Debug, Copy, Clone, PartialEq, Eq)]
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enum CharCategory {
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Separator(SeparatorCategory),
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Cjk,
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Other,
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}
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fn classify_char(c: char) -> CharCategory {
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if let Some(category) = classify_separator(c) {
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CharCategory::Separator(category)
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} else if is_cjk(c) {
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CharCategory::Cjk
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} else {
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CharCategory::Other
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}
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}
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fn is_str_word(s: &str) -> bool {
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!s.chars().any(is_separator)
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}
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fn same_group_category(a: char, b: char) -> bool {
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match (classify_char(a), classify_char(b)) {
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(CharCategory::Cjk, _) | (_, CharCategory::Cjk) => false,
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(CharCategory::Separator(_), CharCategory::Separator(_)) => true,
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(a, b) => a == b,
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}
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}
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// fold the number of chars along with the index position
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fn chars_count_index((n, _): (usize, usize), (i, c): (usize, char)) -> (usize, usize) {
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(n + 1, i + c.len_utf8())
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}
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pub fn split_query_string(query: &str) -> impl Iterator<Item = &str> {
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Tokenizer::new(query).map(|t| t.word)
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}
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#[derive(Debug, Copy, Clone, PartialEq, Eq)]
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pub struct Token<'a> {
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pub word: &'a str,
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pub word_index: usize,
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pub char_index: usize,
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}
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pub struct Tokenizer<'a> {
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inner: &'a str,
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word_index: usize,
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char_index: usize,
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}
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impl<'a> Tokenizer<'a> {
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pub fn new(string: &str) -> Tokenizer {
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// skip every separator and set `char_index`
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// to the number of char trimmed
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let (count, index) = string
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.char_indices()
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.take_while(|(_, c)| is_separator(*c))
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.fold((0, 0), chars_count_index);
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Tokenizer {
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inner: &string[index..],
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word_index: 0,
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char_index: count,
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}
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}
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}
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impl<'a> Iterator for Tokenizer<'a> {
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type Item = Token<'a>;
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fn next(&mut self) -> Option<Self::Item> {
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let mut iter = self.inner.linear_group_by(same_group_category).peekable();
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while let (Some(string), next_string) = (iter.next(), iter.peek()) {
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let (count, index) = string.char_indices().fold((0, 0), chars_count_index);
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if !is_str_word(string) {
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self.word_index += string
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.chars()
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.filter_map(classify_separator)
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.fold(Soft, |a, x| a.merge(x))
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.to_usize();
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self.char_index += count;
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self.inner = &self.inner[index..];
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continue;
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}
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let token = Token {
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word: string,
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word_index: self.word_index,
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char_index: self.char_index,
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};
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if next_string.filter(|s| is_str_word(s)).is_some() {
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self.word_index += 1;
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}
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self.char_index += count;
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self.inner = &self.inner[index..];
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return Some(token);
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}
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self.inner = "";
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None
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}
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}
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pub struct SeqTokenizer<'a, I>
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where
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I: Iterator<Item = &'a str>,
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{
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inner: I,
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current: Option<Peekable<Tokenizer<'a>>>,
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word_offset: usize,
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char_offset: usize,
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}
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impl<'a, I> SeqTokenizer<'a, I>
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where
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I: Iterator<Item = &'a str>,
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{
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pub fn new(mut iter: I) -> SeqTokenizer<'a, I> {
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let current = iter.next().map(|s| Tokenizer::new(s).peekable());
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SeqTokenizer {
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inner: iter,
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current,
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word_offset: 0,
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char_offset: 0,
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}
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}
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}
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impl<'a, I> Iterator for SeqTokenizer<'a, I>
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where
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I: Iterator<Item = &'a str>,
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{
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type Item = Token<'a>;
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fn next(&mut self) -> Option<Self::Item> {
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match &mut self.current {
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Some(current) => {
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match current.next() {
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Some(token) => {
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// we must apply the word and char offsets
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// to the token before returning it
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let token = Token {
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word: token.word,
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word_index: token.word_index + self.word_offset,
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char_index: token.char_index + self.char_offset,
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};
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// if this is the last iteration on this text
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// we must save the offsets for next texts
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if current.peek().is_none() {
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let hard_space = SeparatorCategory::Hard.to_usize();
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self.word_offset = token.word_index + hard_space;
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self.char_offset = token.char_index + hard_space;
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}
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Some(token)
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}
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None => {
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// no more words in this text we must
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// start tokenizing the next text
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self.current = self.inner.next().map(|s| Tokenizer::new(s).peekable());
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self.next()
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}
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}
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}
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// no more texts available
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None => None,
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn easy() {
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let mut tokenizer = Tokenizer::new("salut");
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "salut",
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word_index: 0,
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char_index: 0
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})
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);
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assert_eq!(tokenizer.next(), None);
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let mut tokenizer = Tokenizer::new("yo ");
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "yo",
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word_index: 0,
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char_index: 0
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})
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);
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assert_eq!(tokenizer.next(), None);
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}
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#[test]
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fn hard() {
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let mut tokenizer = Tokenizer::new(" .? yo lolo. aïe (ouch)");
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "yo",
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word_index: 0,
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char_index: 4
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "lolo",
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word_index: 1,
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char_index: 7
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "aïe",
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word_index: 9,
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char_index: 13
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "ouch",
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word_index: 17,
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char_index: 18
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})
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);
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assert_eq!(tokenizer.next(), None);
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let mut tokenizer = Tokenizer::new("yo ! lolo ? wtf - lol . aïe ,");
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "yo",
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word_index: 0,
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char_index: 0
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "lolo",
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word_index: 8,
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char_index: 5
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "wtf",
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word_index: 16,
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char_index: 12
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "lol",
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word_index: 17,
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char_index: 18
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "aïe",
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word_index: 25,
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char_index: 24
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})
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);
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assert_eq!(tokenizer.next(), None);
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}
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#[test]
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fn hard_long_chars() {
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let mut tokenizer = Tokenizer::new(" .? yo 😂. aïe");
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "yo",
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word_index: 0,
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char_index: 4
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "😂",
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word_index: 1,
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char_index: 7
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "aïe",
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word_index: 9,
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char_index: 10
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})
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);
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assert_eq!(tokenizer.next(), None);
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let mut tokenizer = Tokenizer::new("yo ! lolo ? 😱 - lol . 😣 ,");
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "yo",
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word_index: 0,
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char_index: 0
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "lolo",
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word_index: 8,
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char_index: 5
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "😱",
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word_index: 16,
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char_index: 12
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "lol",
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word_index: 17,
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char_index: 16
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "😣",
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word_index: 25,
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char_index: 22
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})
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);
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assert_eq!(tokenizer.next(), None);
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}
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#[test]
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fn hard_kanjis() {
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let mut tokenizer = Tokenizer::new("\u{2ec4}lolilol\u{2ec7}");
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "\u{2ec4}",
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word_index: 0,
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char_index: 0
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "lolilol",
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word_index: 1,
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char_index: 1
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "\u{2ec7}",
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word_index: 2,
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char_index: 8
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})
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);
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assert_eq!(tokenizer.next(), None);
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let mut tokenizer = Tokenizer::new("\u{2ec4}\u{2ed3}\u{2ef2} lolilol - hello \u{2ec7}");
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "\u{2ec4}",
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word_index: 0,
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char_index: 0
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "\u{2ed3}",
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word_index: 1,
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char_index: 1
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "\u{2ef2}",
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word_index: 2,
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char_index: 2
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "lolilol",
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word_index: 3,
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char_index: 4
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "hello",
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word_index: 4,
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char_index: 14
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})
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);
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assert_eq!(
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tokenizer.next(),
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Some(Token {
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word: "\u{2ec7}",
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word_index: 5,
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char_index: 23
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})
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);
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assert_eq!(tokenizer.next(), None);
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}
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}
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