It's still not entirely clear to me what you're doing, but it sounds like you want are (anonymous) sub references.

This code would check if an action correponding to $key is known, determine the action if it's not known, and in either case execute the action:

($actions{$key} ||= determine_action($key))->($key, $data);
[download]

The sub determine_action would have to find out what the correct action is, and return a sub reference to it. If you don't want to make explicit subs, use anonymous ones:

sub determine_action {
    my ($key) = @_
    if (it's first action) {
        return sub {
            my ($key, $data) = @_;
            do stuff;
        };
    elsif (it's second action) {
        return sub {
            my ($key, $data) = @_;
            do stuff;
        };
... etc...
}
[download]