rust macro equivalent for `if ($x == $y) { branch!() }`

lib.rs

macro_rules! match_and_then {
    { $val:tt .. {$( $default_action:tt )*}; $( {$( $pattern:tt )+} => {$( $action:tt )*} ;)*} => {
        macro_rules! __callback_match_and_then {
            $( {$( $pattern )+} => {$( $action )*}; )*
            { $any:tt } => {$( $default_action )*};
        }

        __callback_match_and_then!($val);
    }
}

#[test]
fn try_eat() {
    match_and_then!{
        apple .. { println!("what's that?") };
        { apple } => { println!("yummy!") };
        { nothing } => { println!("I'm starving..") };
    }
}

requires rustc 1.12 (current nightly) - due to line 5 (i.e. the default case).