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=head1 NAME
accessors::ro - create 'classic' read-only accessor methods in caller's package.
=head1 SYNOPSIS
package Foo;
use accessors::ro qw( foo bar baz );
my $obj = bless { foo => 'read only? ' }, 'Foo';
# values are read-only, so set is disabled:
print "oh my!\n" if $obj->foo( "set?" ) eq 'read only? ';
# if you really need to change the vars,
# you must use direct-variable-access:
$obj->{bar} = 'i need a drink ';
$obj->{baz} = 'now';
# always returns the current value:
print $obj->foo, $obj->bar, $obj->baz, "!\n";
=cut
package accessors::ro;
use strict;
use warnings::register;
use base qw( accessors );
our $VERSION = '1.01';
our $REVISION = (split(/ /, ' $Revision: 1.4 $ '))[2];
use constant style => 'ro';
sub create_accessor {
my ($class, $accessor, $property) = @_;
# get is slightly faster if we eval instead of using a closure + anon
# sub, but the difference is marginal (~5%), and this uses less memory...
no strict 'refs';
*{$accessor} = sub { return $_[0]->{$property} };
}
1;
__END__
=head1 DESCRIPTION
The B<accessors::ro> pragma lets you create simple I<classic> read-only
accessors at compile-time.
The generated methods look like this:
sub foo {
my $self = shift;
return $self->{foo};
}
They I<always> return the current value, just like L<accessors::ro>.
=head1 PERFORMANCE
There is B<little-to-no performace hit> when using generated accessors; in
fact there is B<usually a performance gain>.
=over 4
=item *
typically I<5-15% faster> than hard-coded accessors (like the above example).
=item *
typically I<0-15% slower> than I<optimized> accessors (less readable).
=item *
typically a I<small> performance hit at startup (accessors are created at
compile-time).
=item *
uses the same anonymous sub to reduce memory consumption (sometimes by 80%).
=back
See the benchmark tests included with this distribution for more details.
=head1 CAVEATS
Classes using blessed scalarrefs, arrayrefs, etc. are not supported for sake
of simplicity. Only hashrefs are supported.
=head1 AUTHOR
Steve Purkis <spurkis@cpan.org>
=head1 SEE ALSO
L<accessors>,
L<accessors::rw>,
L<accessors::classic>,
L<accessors::chained>,
L<base>
=cut
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