gistfile1.txt

multi trait_mod:<is>(Routine:D $r, :$pre-check) {
    $r does role {
        method postcircumfix:<( )>(|) {
            say 'before';
            my $result = callsame;
            say 'after';

            say "result = $result";

            $result
        }   
    }   
}

sub mysub is pre-check {
    say 'there';
    17  
}

mysub();