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//! Utilities to deal with lists of events.
use crate::tokenizer::{Event, TokenType};
/// Skip from `index`, optionally past `token_types`.
pub fn opt(events: &[Event], index: usize, token_types: &[TokenType]) -> usize {
skip_opt_with_direction(events, index, token_types, true)
}
/// Skip from `index`, optionally past `token_types`, backwards.
pub fn opt_back(events: &[Event], index: usize, token_types: &[TokenType]) -> usize {
skip_opt_with_direction(events, index, token_types, false)
}
/// Skip internals.
fn skip_opt_with_direction(
events: &[Event],
index: usize,
token_types: &[TokenType],
forward: bool,
) -> usize {
let mut index = index;
while index < events.len() {
let current = &events[index].token_type;
if !token_types.contains(current) {
break;
}
// assert_eq!(events[index].event_type, EventType::Enter);
index = if forward { index + 1 } else { index - 1 };
loop {
if events[index].token_type == *current {
// assert_eq!(events[index].event_type, EventType::Exit);
index = if forward { index + 1 } else { index - 1 };
break;
}
index = if forward { index + 1 } else { index - 1 };
}
}
index
}
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