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package Reaction::Meta::Attribute;
use Moose;
extends 'Moose::Meta::Attribute';
#is => 'Bool' ? or leave it open
has lazy_fail =>
(is => 'ro', reader => 'is_lazy_fail', required => 1, default => 0);
has lazy_build =>
(is => 'ro', reader => 'is_lazy_build', required => 1, default => 0);
around _process_options => sub {
my $super = shift;
my ($class, $name, $options) = @_;
my $fail = $options->{lazy_fail}; #will this autovivify?
my $build = $options->{lazy_build};
if ( $fail || $build) {
confess("You may not use both lazy_build and lazy_fail for one attribute")
if $fail && $build;
confess("You may not supply a default value when using lazy_build or lazy_fail")
if exists $options->{default};
$options->{lazy} = 1;
$options->{required} = 1;
my $builder = ($name =~ /^_/) ? "_build${name}" : "build_${name}";
$options->{default} = $fail ?
sub { confess "${name} must be provided before calling reader" } :
sub{ shift->$builder };
$options->{clearer} ||= ($name =~ /^_/) ? "_clear${name}" : "clear_${name}"
if $build;
}
#we are using this everywhere so might as well move it here.
$options->{predicate} ||= ($name =~ /^_/) ? "_has${name}" : "has_${name}"
if !$options->{required} || $options->{lazy};
$super->($class, $name, $options);
};
1;
__END__;
=head1 NAME
Reaction::Meta::Attribute
=head1 SYNOPSIS
has description => (is => 'rw', isa => 'Str', lazy_fail => 1);
# OR
has description => (is => 'rw', isa => 'Str', lazy_build => 1);
sub build_description{ "My Description" }
# OR
has _description => (is => 'rw', isa => 'Str', lazy_build => 1);
sub _build_description{ "My Description" }
=head1 Method-naming conventions
Reaction::Meta::Attribute will never override the values you set for method names,
but if you do not it will follow these basic rules:
Attributes with a name that starts with an underscore will default to using
builder and predicate method names in the form of the attribute name preceeded by
either "_has" or "_build". Otherwise the method names will be in the form of the
attribute names preceeded by "has_" or "build_". e.g.
#auto generates "_has_description" and expects "_build_description"
has _description => (is => 'rw', isa => 'Str', lazy_build => 1);
#auto generates "has_description" and expects "build_description"
has description => (is => 'rw', isa => 'Str', lazy_build => 1);
=head2 Predicate generation
All non-required or lazy attributes will have a predicate automatically
generated for them if one is not already specified.
=head2 lazy_fail
=head2 lazy_build
lazy_build will lazily build to the return value of a user-supplied builder sub
The builder sub will recieve C<$self> as the first argument.
lazy_fail will simply fail if it is called without first having set the value.
=head1 AUTHORS
See L<Reaction::Class> for authors.
=head1 LICENSE
See L<Reaction::Class> for the license.
=cut
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