Trait aoc_parse::ParseIter

pub trait ParseIter<'parse> {
    type RawOutput;

    fn match_end(&self) -> usize;
    fn backtrack(
        &mut self,
        context: &mut ParseContext<'parse>
    ) -> Result<(), Reported>;
    fn into_raw_output(self) -> Self::RawOutput;
}

A parser in action. Some parsers can match in several different ways (for example, in foo* bar backtracking is accomplished by foo* first matching as much as possible, then backing off one match at a time), so this is an iterator.

This doesn’t return a RawOutput value from next_parse but instead waits until you’re sure you have a complete, successful parse, and are thus ready to destroy the iterator. This helps us avoid building values only to drop them later when some downstream parser fails to match, so it makes backtracking faster. It also means we don’t call .map closures until there is a successful overall match and the values are actually needed.

Required Associated Types

type RawOutput

The type this iterator can produce on a successful match.

Required Methods

fn match_end(&self) -> usize

Position at the end of the current match.

fn backtrack(
    &mut self,
    context: &mut ParseContext<'parse>
) -> Result<(), Reported>

Reject the current match and find the next-most-preferable match. Returns true if another match was found, false if not.

Once this returns false, no more method calls should be made.

fn into_raw_output(self) -> Self::RawOutput

Consume this iterator to extract data.

Implementors