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package List::Objects::WithUtils::Role::Hash::Immutable;
$List::Objects::WithUtils::Role::Hash::Immutable::VERSION = '2.028003';
use strictures 2;
use Carp ();
use Tie::Hash ();
sub _make_unimp {
my ($method) = @_;
sub {
local $Carp::CarpLevel = 1;
Carp::croak "Method '$method' not implemented on immutable hashes"
}
}
our @ImmutableMethods = qw/
clear
set
maybe_set
delete
/;
use Role::Tiny;
requires 'new', @ImmutableMethods;
around is_mutable => sub { () };
around new => sub {
my ($orig, $class) = splice @_, 0, 2;
my $self = $class->$orig(@_);
# This behavior changed in c. 45f59a73 --
# we can revert back if Hash::Util gains the flexibility discussed on p5p
# (lock_keys without an exception on unknown key retrieval)
# For now, take the tie performance hit :(
tie %$self, 'Tie::StdHash' and %$self = @_
unless tied %$self;
Role::Tiny->apply_roles_to_object( tied(%$self),
'List::Objects::WithUtils::Role::Hash::TiedRO'
);
$self
};
around $_ => _make_unimp($_) for @ImmutableMethods;
1;
=pod
=head1 NAME
List::Objects::WithUtils::Role::Hash::Immutable - Immutable hash behavior
=head1 SYNOPSIS
# Via List::Objects::WithUtils::Hash::Immutable ->
use List::Objects::WithUtils 'immhash';
my $hash = immhash( foo => 1, bar => 2 );
$hash->set(foo => 3); # dies
=head1 DESCRIPTION
This role adds immutable behavior to L<List::Objects::WithUtils::Role::Hash>
consumers.
The following methods are not available and will throw an exception:
clear
set
maybe_set
delete
(The backing hash is also marked read-only.)
See L<List::Objects::WithUtils::Hash::Immutable> for a consumer
implementation.
=head1 AUTHOR
Jon Portnoy <avenj@cobaltirc.org>
=cut
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