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use alloc::rc::Rc;
use alloc::vec::Vec;
use core::fmt;
use core::str;
use super::queueable_token::QueueableToken;
use crate::position;
use crate::token::Token;
use crate::RuleType;
#[derive(Clone)]
pub struct Tokens<'i, R> {
queue: Rc<Vec<QueueableToken<R>>>,
input: &'i str,
start: usize,
end: usize,
}
pub fn new<R: RuleType>(
queue: Rc<Vec<QueueableToken<R>>>,
input: &str,
start: usize,
end: usize,
) -> Tokens<'_, R> {
if cfg!(debug_assertions) {
for tok in queue.iter() {
match *tok {
QueueableToken::Start { input_pos, .. } | QueueableToken::End { input_pos, .. } => {
assert!(
input.get(input_pos..).is_some(),
"💥 UNSAFE `Tokens` CREATED 💥"
)
}
}
}
}
Tokens {
queue,
input,
start,
end,
}
}
impl<'i, R: RuleType> Tokens<'i, R> {
fn create_token(&self, index: usize) -> Token<'i, R> {
match self.queue[index] {
QueueableToken::Start {
end_token_index,
input_pos,
} => {
let rule = match self.queue[end_token_index] {
QueueableToken::End { rule, .. } => rule,
_ => unreachable!(),
};
Token::Start {
rule,
pos: unsafe { position::Position::new_unchecked(self.input, input_pos) },
}
}
QueueableToken::End {
rule, input_pos, ..
} => {
Token::End {
rule,
pos: unsafe { position::Position::new_unchecked(self.input, input_pos) },
}
}
}
}
}
impl<'i, R: RuleType> Iterator for Tokens<'i, R> {
type Item = Token<'i, R>;
fn next(&mut self) -> Option<Self::Item> {
if self.start >= self.end {
return None;
}
let token = self.create_token(self.start);
self.start += 1;
Some(token)
}
}
impl<'i, R: RuleType> DoubleEndedIterator for Tokens<'i, R> {
fn next_back(&mut self) -> Option<Self::Item> {
if self.end <= self.start {
return None;
}
let token = self.create_token(self.end - 1);
self.end -= 1;
Some(token)
}
}
impl<'i, R: RuleType> fmt::Debug for Tokens<'i, R> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_list().entries(self.clone()).finish()
}
}
#[cfg(test)]
mod tests {
use super::super::super::macros::tests::*;
use super::super::super::Parser;
use super::Token;
use alloc::vec::Vec;
#[test]
fn double_ended_iter_for_tokens() {
let pairs = AbcParser::parse(Rule::a, "abcde").unwrap();
let mut tokens = pairs.clone().tokens().collect::<Vec<Token<'_, Rule>>>();
tokens.reverse();
let reverse_tokens = pairs.tokens().rev().collect::<Vec<Token<'_, Rule>>>();
assert_eq!(tokens, reverse_tokens);
}
}