given ( $c ) {
    when ( 'a' ) {
        say 'a';
    }
    when ( 'b' ) {
        say 'b';
    }
    when ( $extra == 1 and $c eq 'd' ) {
        say 'd';
    }
    when ( $extra == 1 and $c eq 'e' ) {
        say 'e';
    }
    when ( 'z' ) {
        say 'z';
    }
    default {
        say 'something else';
    }
}