File: Class.pm

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libclass-accessor-class-perl 0.504-1
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use strict;
use warnings;
package Class::Accessor::Class 0.504;
use Class::Accessor 0.16 ();
use parent 'Class::Accessor';
# ABSTRACT: simple class variable accessors

#pod =head1 SYNOPSIS
#pod
#pod Set up a module with class accessors:
#pod
#pod  package Text::Fortune;
#pod
#pod  use base qw(Class::Accessor::Class Exporter);
#pod  Robot->mk_class_accessors(qw(language offensive collection));
#pod
#pod  sub fortune { 
#pod    if (__PACKAGE__->offensive) {
#pod 	 ..
#pod
#pod Then, when using the module:
#pod
#pod  use Text::Fortune;
#pod
#pod  Text::Fortune->offensive(1);
#pod
#pod  print fortune; # prints an offensive fortune
#pod
#pod  Text::Fortune->language('EO');
#pod
#pod  print fortune; # prints an offensive fortune in Esperanto
#pod
#pod =head1 DESCRIPTION
#pod
#pod Class::Accessor::Class provides a simple way to create accessor and mutator
#pod methods for class variables, just as Class::Accessor provides for objects.  It
#pod can use either an enclosed lexical variable, or a package variable.
#pod
#pod This module was once implemented in terms of Class::Accessor, but changes to
#pod that module broke this relationship.  Class::Accessor::Class is still a
#pod subclass of Class::Accessor, strictly for historical reasons.  As a side
#pod benefit, a class that isa Class::Accessor::Class is also a Class::Accessor
#pod and can use its methods.
#pod
#pod =method mk_class_accessors
#pod
#pod  package Foo;
#pod  use base qw(Class::Accessor::Class);
#pod  Foo->mk_class_accessors(qw(foo bar baz));
#pod
#pod  Foo->foo(10);
#pod  my $obj = new Foo;
#pod  print $obj->foo;   # 10
#pod
#pod This method adds accessors for the named class variables.  The accessor will
#pod get or set a lexical variable to which the accessor is the only access.
#pod
#pod =cut

sub mk_class_accessors {
	my ($self, @fields) = @_;

  ## no critic (ProhibitNoStrict)
  no strict 'refs';
  for my $field (@fields) {
    *{"${self}::$field"} = $self->make_class_accessor($field);
  }
}

#pod =method mk_package_accessors
#pod
#pod  package Foo;
#pod  use base qw(Class::Accessor::Class);
#pod  Foo->mk_package_accessors(qw(foo bar baz));
#pod
#pod  Foo->foo(10);
#pod  my $obj = new Foo;
#pod  print $obj->foo;   # 10
#pod  print $Foo::foo;    # 10
#pod
#pod This method adds accessors for the named class variables.  The accessor will
#pod get or set the named variable in the package's symbol table.
#pod
#pod =cut

sub mk_package_accessors {
	my ($self, @fields) = @_;

  ## no critic (ProhibitNoStrict)
  no strict 'refs';
  for my $field (@fields) {
    *{"${self}::$field"} = $self->make_package_accessor($field);
  }
}

#pod =head1 DETAILS
#pod
#pod =head2 make_class_accessor
#pod
#pod  $accessor = Class->make_class_accessor($field);
#pod
#pod This method generates a subroutine reference which acts as an accessor for the
#pod named field. 
#pod
#pod =cut

{
	my %accessor;

	sub make_class_accessor {
		my ($class, $field) = @_;

		return $accessor{$class}{$field}
			if $accessor{$class}{$field};

		my $field_value;

		$accessor{$class}{$field} = sub {
			my $class = shift;

			return @_
				? ($field_value = $_[0])
				:  $field_value;
		}
	}
}

#pod =head2 make_package_accessor
#pod
#pod  $accessor = Class->make_package_accessor($field);
#pod
#pod This method generates a subroutine reference which acts as an accessor for the
#pod named field, which is stored in the scalar named C<field> in C<Class>'s symbol
#pod table.
#pod
#pod This can be useful for dealing with legacy code, but using package variables is
#pod almost never a good idea for new code.  Use this with care.
#pod
#pod =cut

sub make_package_accessor {
	my ($self, $field) = @_;
	my $class = ref $self || $self;

	my $varname = "$class\:\:$field";
	return sub {
		my $class = shift;

    ## no critic (ProhibitNoStrict)
    no strict 'refs';
		return @_
			? (${$varname} = $_[0])
			:  ${$varname}
	}
}

1;

__END__

=pod

=encoding UTF-8

=head1 NAME

Class::Accessor::Class - simple class variable accessors

=head1 VERSION

version 0.504

=head1 SYNOPSIS

Set up a module with class accessors:

 package Text::Fortune;

 use base qw(Class::Accessor::Class Exporter);
 Robot->mk_class_accessors(qw(language offensive collection));

 sub fortune { 
   if (__PACKAGE__->offensive) {
	 ..

Then, when using the module:

 use Text::Fortune;

 Text::Fortune->offensive(1);

 print fortune; # prints an offensive fortune

 Text::Fortune->language('EO');

 print fortune; # prints an offensive fortune in Esperanto

=head1 DESCRIPTION

Class::Accessor::Class provides a simple way to create accessor and mutator
methods for class variables, just as Class::Accessor provides for objects.  It
can use either an enclosed lexical variable, or a package variable.

This module was once implemented in terms of Class::Accessor, but changes to
that module broke this relationship.  Class::Accessor::Class is still a
subclass of Class::Accessor, strictly for historical reasons.  As a side
benefit, a class that isa Class::Accessor::Class is also a Class::Accessor
and can use its methods.

=head1 PERL VERSION SUPPORT

This code is effectively abandonware.  Although releases will sometimes be made
to update contact info or to fix packaging flaws, bug reports will mostly be
ignored.  Feature requests are even more likely to be ignored.  (If someone
takes up maintenance of this code, they will presumably remove this notice.)

=head1 METHODS

=head2 mk_class_accessors

 package Foo;
 use base qw(Class::Accessor::Class);
 Foo->mk_class_accessors(qw(foo bar baz));

 Foo->foo(10);
 my $obj = new Foo;
 print $obj->foo;   # 10

This method adds accessors for the named class variables.  The accessor will
get or set a lexical variable to which the accessor is the only access.

=head2 mk_package_accessors

 package Foo;
 use base qw(Class::Accessor::Class);
 Foo->mk_package_accessors(qw(foo bar baz));

 Foo->foo(10);
 my $obj = new Foo;
 print $obj->foo;   # 10
 print $Foo::foo;    # 10

This method adds accessors for the named class variables.  The accessor will
get or set the named variable in the package's symbol table.

=head1 DETAILS

=head2 make_class_accessor

 $accessor = Class->make_class_accessor($field);

This method generates a subroutine reference which acts as an accessor for the
named field. 

=head2 make_package_accessor

 $accessor = Class->make_package_accessor($field);

This method generates a subroutine reference which acts as an accessor for the
named field, which is stored in the scalar named C<field> in C<Class>'s symbol
table.

This can be useful for dealing with legacy code, but using package variables is
almost never a good idea for new code.  Use this with care.

=head1 AUTHOR

Ricardo SIGNES <rjbs@semiotic.systems>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2004 by Ricardo SIGNES.

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

=cut