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Re: Abstract Methods in Moose

by brap (Pilgrim)
on Dec 11, 2009 at 19:45 UTC ( #812424=note: print w/replies, xml ) Need Help??

in reply to Abstract Methods in Moose

I could be way off (just trying to learn Moose myself), but are you maybe looking for

requires 'get_widget_type';

in the base class by chance?

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Re^2: Abstract Methods in Moose
by crashtest (Curate) on Dec 11, 2009 at 20:17 UTC

    Hm. I believe the requires is provided by Moose::Role, and hence has the limitations outlined in the documentation.

    What it comes down is that while I can use a role to require a method definition directly in a class, I can't "defer" the method definition until later in the class hierarchy. That is, the following would work:

    package WidgetRole; use Moose::Role; requires 'get_widget_type'; package AbstractWidget; use Moose; with 'WidgetRole'; sub get_widget_type{ "IAmAbstract" }
    but the following (which is what I'd want) wouldn't:
    package WidgetRole; use Moose::Role; requires 'get_widget_type'; package AbstractWidget; use Moose; with 'WidgetRole'; package SnazzyWidget; use Moose; extends 'AbstractWidget'; sub get_widget_type{ "BasicWidget" } # throws error and dies

    So I don't think roles/using requires is what I am looking for. But maybe I'm wrong - I have all of five days of experience with Moose!

      Why do you have a role and and a base class? You should use a role instead of a base class. All you need is
      package Widget::Role; # Formerly Widget::Abstract use Moose::Role; requires qw( get_widget_type ); # Abstract methods ... # Other attributes and methods. 1;
      package Widget::Snazzy; use Moose; with qw( Widget::Role ); sub get_widget_type { __PACKAGE__ } ... 1;
      imho roles are theabstract part and the class that consumes is muchh more concrete

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