X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FMooseX%2FUndefTolerant.pm;h=c437b9243a0cb2e45603c48153838b1f89cb7ba3;hb=1925805868ca4720ef9865a976f05a202ed2f865;hp=419a7b435893d8c85a83b2f9017a7483a62f3167;hpb=5447ee457d5fd503926799cb8efb8552bdb4764d;p=gitmo%2FMooseX-UndefTolerant.git diff --git a/lib/MooseX/UndefTolerant.pm b/lib/MooseX/UndefTolerant.pm index 419a7b4..c437b92 100644 --- a/lib/MooseX/UndefTolerant.pm +++ b/lib/MooseX/UndefTolerant.pm @@ -1,27 +1,15 @@ package MooseX::UndefTolerant; -use strict; -use warnings; use Moose qw(); use Moose::Exporter; -use Moose::Util::MetaRole; use MooseX::UndefTolerant::Attribute; our $VERSION = '0.01'; -Moose::Exporter->setup_import_methods(); - -sub init_meta { - my (undef, %options) = @_; - - Moose->init_meta(%options); - - return Moose::Util::MetaRole::apply_metaclass_roles( - for_class => $options{for_class}, - attribute_metaclass_roles => [ 'MooseX::UndefTolerant::Attribute' ] - ); -} +Moose::Exporter->setup_import_methods( + attribute_metaclass_roles => [ 'MooseX::UndefTolerant::Attribute' ] +); 1; @@ -29,12 +17,81 @@ __END__ =head1 NAME -MooseX::Attribute::UndefTolerant - The great new MooseX::Attribute::UndefTolerant! +MooseX::UndefTolerant - Make your attribute(s) tolerant to undef intitialization =head1 SYNOPSIS - use MooseX::Attribute::UndefTolerant; + package My::Class; + + use Moose; + use MooseX::UndefTolerant; + + has 'name' => ( + is => 'ro', + isa => 'Str', + predicate => 'has_name' + ); + + # Meanwhile, under the city... + + # Doesn't explode + my $class = My::Class->new(name => undef); + $class->has_name # False! + +Or, if you only want one attribute to have this behaviour: + + package My:Class; + use Moose; + + use MooseX::UndefTolerant::Attribute; + + has 'bar' => ( + traits => [ qw(MooseX::UndefTolerant::Attribute)], + is => 'ro', + isa => 'Num', + predicate => 'has_bar' + ); + +=head1 DESCRIPTION + +Loading this module in your L class makes initialization of your +attributes tolerant of undef. If you specify the value of undef to any of +the attributes they will not be initialized. Effectively behaving as if you +had not provided a value at all. +=head1 MOTIVATION + +I often found myself in this quandry: + + package My:Class; + use Moose; + + has 'foo' => ( + is => 'ro', + isa => 'Str', + ); + + # ... then + + my $foo = ... # get the param from something + + my $class = My:Class->new(foo => $foo, bar => 123); + +What if foo is undefined? I didn't want to change my attribute to be +Maybe[Str] and I still want my predicate (C) to work. The only +real solution was: + + if(defined($foo)) { + $class = My:CLass->new(foo => $foo, bar => 123); + } else { + $class = My:CLass->new(bar => 123); + } + +Or some type of codemulch using ternarys. This module allows you to make +your attributes more tolerant of undef so that you can keep the first +example: have your cake and eat it too! + +=head1 PER ATTRIBUTE =head1 AUTHOR @@ -42,6 +99,8 @@ Cory G Watson, C<< >> =head1 ACKNOWLEDGEMENTS +Many thanks to the crew in #moose who talked me through this module: + Hans Dieter Pearcey (confound) Jesse Luehrs (doy) @@ -64,5 +123,4 @@ by the Free Software Foundation; or the Artistic License. See http://dev.perl.org/licenses/ for more information. - =cut