Function pear::parsers::take_some_while

pub fn take_some_while<I, F>(input: &mut Pear<I>, cond: F) -> Result<I::Many, I> where
    I: Input,
    F: FnMut(&I::Token) -> bool, 

Consumes tokens while cond matches and returns them. Succeeds only if at least one token matched cond.