Function memoize 

pub fn memoize<'input, P, T: Clone, ComputeFn, CacheFn>(
    parser: &mut P,
    cache_fn: CacheFn,
    offset: usize,
    compute_fn: ComputeFn,
) -> ParseResult<'input, T>
where
    CacheFn: FnMut(&mut P) -> &mut Cache<'input, T>,
    ComputeFn: FnOnce(&mut P) -> ParseResult<'input, T>,