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use std::fmt;
use std::rc::Rc;
use super::queueable_token::QueueableToken;
use RuleType;
use position;
use token::Token;
#[derive(Clone)]
pub struct Tokens<'i, R> {
queue: Rc<Vec<QueueableToken<R>>>,
input: &'i [u8],
start: usize,
end: usize
}
pub fn new<R: RuleType>(
queue: Rc<Vec<QueueableToken<R>>>,
input: &[u8],
start: usize,
end: usize
) -> Tokens<R> {
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::new(self.input, input_pos) }
}
}
QueueableToken::End {
rule, input_pos, ..
} => {
Token::End {
rule,
pos: unsafe { position::new(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::Token;
use super::super::super::Parser;
use super::super::super::macros::tests::*;
#[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);
}
}