Not so much a blog post, more a blog question.
When you are 'extend'ing a Moose base class, Attributes can be extended
package Super::Hero;
use Moose;
has q{super_abilitity} => (isa => q{Str}, is => q{rw});
...
package My::Hero;
use Moose;
extends qw{Super::Hero};
has q{+super_abilitity} => (required => 1);
...
However, in this case, I would like Super::Hero to be a Role to be consumed by some class.
package Super::Hero;
use Moose::Role;
has q{super_abilitity} => (isa => q{Str}, is => q{rw});
...
However, the following doesn't work:
package My::Hero;
use Moose;
with qw{Super::Hero};
has q{+super_abilitity} => (required => 1);
...
The required 'extension' is just ignored. I have to actually declare the whole attribute again.
package My::Hero;
use Moose;
with qw{Super::Hero};
has q{super_abilitity} => (isa => q{Str}, is => q{ro}, required => 1);
...
I can't find anything in CPAN Documentation to confirm or deny that this the deliberate design. Does anyone have any suggestions as to any solutions to this?
Any help appreciated.
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3 comments:
That's because you "consume" roles not "extend" them. Thus all your "My::Hero" class needs to do to get the "Super::Hero" "super_ability" is to include the following line of code:
with 'Super::Hero';
Thanks for your reply.
I was really wondering if there is a way to alter something you are consuming, rather than needing to overwrite it. It looks like that seems to be a rule of Roles, you don't get to tamper with them, just not use (exclude and/or overwrite) their attributes/methods.
But again, thankyou for taking the time to reply. BTW, where are you a Computer Biologist in Cambridge, UK?
Forget where are you working question, I found out that we both work at the Sanger through my boss. I could be interested in discussing you Parallelize.pm module at some time.
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