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use std::rc::Rc;
use super::queueable_token::QueueableToken;
use position;
use RuleType;
use token::Token;
#[derive(Clone, Debug)]
pub struct Tokens<'i, R> {
queue: Rc<Vec<QueueableToken<R>>>,
input: &'i str,
index: usize,
start: usize,
end: usize,
}
pub fn new<R: RuleType>(
queue: Rc<Vec<QueueableToken<R>>>,
input: &str,
start: usize,
end: usize
) -> Tokens<R> {
Tokens {
queue,
input,
index: 0,
start,
end,
}
}
impl<'i, R: RuleType> Iterator for Tokens<'i, R> {
type Item = Token<'i, R>;
fn next(&mut self) -> Option<Self::Item> {
if self.index == self.end {
return None;
}
let token = match self.queue[self.index] {
QueueableToken::Start { pair, pos } => {
let rule = match self.queue[pair] {
QueueableToken::End { rule, .. } => rule,
_ => unreachable!()
};
Token::Start {
rule,
pos: unsafe { position::new(self.input, pos) }
}
}
QueueableToken::End { rule, pos } => {
Token::End {
rule,
pos: unsafe { position::new(self.input, pos) }
}
}
};
self.index += 1;
Some(token)
}
}