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use std::rc::Rc;
use super::queueable_token::QueueableToken;
use super::super::inputs::{Input, position};
use super::super::RuleType;
use super::super::token::Token;
#[derive(Debug)]
pub struct TokenIterator<R, I: Input> {
queue: Rc<Vec<QueueableToken<R>>>,
input: Rc<I>,
index: usize,
start: usize,
end: usize
}
pub fn new<R: RuleType, I: Input>(
queue: Rc<Vec<QueueableToken<R>>>,
input: Rc<I>,
start: usize,
end: usize
) -> TokenIterator<R, I> {
TokenIterator {
queue: queue,
input: input,
index: 0,
start: start,
end: end
}
}
impl<R: RuleType, I: Input> Iterator for TokenIterator<R, I> {
type Item = Token<R, I>;
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: rule,
pos: unsafe { position::new(self.input.clone(), pos) }
}
}
QueueableToken::End { rule, pos } => {
Token::End {
rule: rule,
pos: unsafe { position::new(self.input.clone(), pos) }
}
}
};
self.index += 1;
Some(token)
}
}
impl<R: Clone, I: Input> Clone for TokenIterator<R, I> {
fn clone(&self) -> TokenIterator<R, I> {
TokenIterator {
queue: self.queue.clone(),
input: self.input.clone(),
index: self.index,
start: self.start,
end: self.end
}
}
}