nom::consumer_from_parser

macro_rules! consumer_from_parser {
    ($name:ident<$input:ty, $output:ty>, $submac:ident!( $($args:tt)* )) => { ... };
    ($name:ident<$output:ty>, $submac:ident!( $($args:tt)* )) => { ... };
    ($name:ident<$input:ty, $output:ty>, $f:expr) => { ... };
    ($name:ident<$output:ty>, $f:expr) => { ... };
}