Macro goto::gpoint

macro_rules! gpoint {
    [ $n:tt + $n2:tt + $n3:tt $e:tt: $($tt: tt)* ] => { ... };
    [ $n:tt + $n2:tt + $n3:tt : $($tt: tt)* ] => { ... };
    [ $n:tt + $n2:tt $e:tt: $($tt: tt)* ] => { ... };
    [ $n:tt + $n2:tt : $($tt: tt)* ] => { ... };
    [ $n:tt $e:tt: $($tt:tt)* ] => { ... };
    [ $n:tt : $($tt:tt)* ] => { ... };
}

"GOTO point", allows you to return to this line later.