Re: Question (#2) about Apocalypse 6 : Can "is" properties by specified indirectly?

[Damian Conway]

Austin Hastings asked:

How do I specify an array which may be appended/pushed, but whose
values cannot change?
I believe you'd have to create a class for such things, derived from Array:

        class AppOnlyArray is Array {
                method STORE(int $index, $value) {
                        fail "Can't modify existing element"
                                if 0 <= $index < .length;
                        .SUPER::STORE($index, $value);
                }
        }
	my @array is AppOnlyArray;


How do I specify a hash whose current keys/values are fixed, but which
can accept new keys/values?
Same story.

Damian