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NAME
    MooseX::hasn't - syntactic sugar to complement "has"

SYNOPSIS
     {
       package Person;
       use Moose;
       has name => (is => "ro", writer => "_rename", required => 1);
     }
 
     {
       package AnonymousPerson;
       use Moose;
       use MooseX::hasn't;
       extends "Person";
       hasn't name => ();
     }
 
     my $dude  = AnonymousPerson->new;
     say($dude->can('_rename') ? 'true' : 'false');  # false
     say($dude->name);                               # croaks

DESCRIPTION
    `hasn't` is a counter-part for Moose's `has`.

    It tries to stop a child class inheriting something (an attribute or a
    method) from its parent class - though it's not always 100% successful.

FAQ
  Doesn't this break polymorphism?
    The idea behind polymorphism is that if *Bar* inherits from *Foo*, then I
    should be able to use an object of type *Bar* wherever I'd normally use
    *Foo*.

    In particular, if I can do:

     Foo->new()->some_method();

    then I should be able to do:

     Bar->new()->some_method();

    But if *Bar* can explicitly indicate that it hasn't got method
    `some_method` then this breaks. So, yes, this module does break
    polymorphism.

    But observe that it's not especially difficult to break polymorphism
    manually:

     {
       package Foo;
       use Moose;
       sub some_method {}
     }
 
     {
       package Bar;
       use Moose;
       extends 'Foo';
       sub some_method { die "some_method not found in package Bar" }
     }

    This module just makes it easier and more declarative.

  How exactly is this achieved?
    For `hasn't $method`, it simply adds an override method modifier to the
    given method that croaks.

    For `hasn't $attribute`, it finds the names of the accessor, reader,
    writer, clearer, predicate and initializer methods for that attribute (if
    any) and overrides them all.

    In both cases, it overrides the class' `can` method too.

  What about required attributes?
    If the parent class has an attribute which is required and has a default,
    then you can use `hasn't` in a child class safely.

    If the parent class has an attribute which is required but has no default,
    then you must explicitly specify a default in the child class:

     hasn't name => (default => 'anon');

    This latter technique is probably not foolproof. Defaults may be coderefs,
    like in `has`.

BUGS AND LIMITATIONS
    *   `hasn't $attr (default => sub {})` will execute the coderef as a
        function with no arguments, not as a method.

    *   `$object->meta` can still see attributes and methods which have been
        "hasn'ted". Some serious Class::MOP fu is needed to fix this.

    Report anything else here:

    <http://rt.cpan.org/Dist/Display.html?Queue=Moose-hasn-t>.

SEE ALSO
    Moose.

AUTHOR
    Toby Inkster <[email protected]>.

COPYRIGHT AND LICENCE
    This software is copyright (c) 2012 by Toby Inkster.

    This is free software; you can redistribute it and/or modify it under the
    same terms as the Perl 5 programming language system itself.

DISCLAIMER OF WARRANTIES
    THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
    WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
    MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.