Thanks a lot for this example. Many lessons learned. :-)

Starting to grok the code, I 1st wondered why the type constraints do not need to be written in a string. It seems use MooseX::Types::Moose is responsible for being able to do that.

I wondered if it will "do the right thing" if confronted with multiple inheritance and added a "JustTesting" class like so 
package JustTesting;

use strict;
use warnings;

use Moose;
use MooseX::Types::Moose -all;

has 'data' => (
    is      => 'ro',
    isa     => CodeRef,
);

[download]

and then of course used extends 'KeyAtom', 'JustTesting'; in the ValAtom class definition. A subsequent my $atom4 = ValAtom->new(sub {});

throws an error 
Attribute (data) does not pass the type constraint because: Validation
+ failed for 'ArrayRef|RegexpRef|Str|HashRef' with value CODE(0x25d85c
+0) ...

[download]

Indicating, that only the 1st one in the inheritance hierarchy gets propagated. So I assume for it to work independent of how many parent classes were passed, one would have to loop over them in _existing_constraint (how?) and buildup the type constraint before returning it.

Thanks also for the +data hint, that somehow fell of my stack. Although I ask myself what happens if a inheriting class uses +data and some parents have 'rw' while others have e.g. 'ro'.

Bye
 PetaMem     All Perl:   MT, NLP, NLU

In reply to Re^2: Moose "unions" and inheritance by PetaMem
in thread Moose "unions" and inheritance by PetaMem

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