Function parsell::character_map

pub fn character_map<F>(f: F) -> Map<Character<IsSome<F>>, Unwrap<F>> where F: Copy

An uncommitted parser that reads one character and applies a function to it.

The parser character_map(f) reads one character ch from the input, if f(ch) is Some(value) then it commits and the result is value, otherwise it backtracks.

This requires characters to be copyable.