Macro nom::exact

macro_rules! exact {
    ($i:expr, $submac:ident!( $($args:tt)* )) => { ... };
    ($i:expr, $f:expr) => { ... };
}

exact!() will fail if the child parser does not consume the whole data

This combinator works with the AtEof trait that input types must implement. If an input type's at_eof method returns true, it means there will be no more refills (like what happens when buffering big files).

TODO: example