It's a bit hard to know what you're trying to do here, but I really don't like that hash of methods. Consider making the return value of GetID into an object and have $some_param dispatch to it. Then your switch becomes

for my $i (0 .. $SomeValue - 1) {
  $SomeArray[$i]{value} = $some_param->dispatched_method()
}

sub SomeParamClass::dispatched_method {
  my $self = shift;
  $self->getID->dispatch_method_to($self);
}
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You can move any other 'switched' behaviour onto your ID classes and get rid of multiple CaseToMethod hashes in the process. If you think that making the ID into an object is overkill then you can at least move the CaseToMethod hashes into your parameter class's defintion. Or, if the method called only varies with the class of the parameter just create a dispatched_method methods on each parameter class.