package App::Ack::Filter;
=head1 NAME
App::Ack::Filter
=head1 DESCRIPTION
An abstract superclass that represents objects that can filter `App::Ack::Resource` objects.
=cut
use strict;
use warnings;
use App::Ack::Filter::Inverse ();
use Carp 1.04 ();
my %filter_types;
=head1 NAME
App::Ack::Filter - Filter objects to filter files
=head1 SYNOPSIS
# filter implementation
package MyFilter;
use strict;
use warnings;
use base 'App::Ack::Filter';
sub filter {
my ( $self, $resource ) = @_;
}
BEGIN {
App::Ack::Filter->register_filter('mine' => __PACKAGE__);
}
1;
# users
App::Ack::Filter->create_filter('mine', @args);
=head1 DESCRIPTION
App::Ack::Filter implementations are responsible for filtering filenames
to be searched.
=head1 METHODS
=head2 App::Ack:Filter->create_filter($type, @args)
Creates a filter implementation, registered as C<$type>. C<@args>
are provided as additional arguments to the implementation's constructor.
=cut
sub create_filter {
my ( undef, $type, @args ) = @_;
if ( my $package = $filter_types{$type} ) {
return $package->new(@args);
}
Carp::croak "Unknown filter type '$type'";
}
=head2 App::Ack:Filter->register_filter($type, $package)
Registers a filter implementation package C<$package> under
the name C<$type>.
=cut
sub register_filter {
my ( undef, $type, $package ) = @_;
$filter_types{$type} = $package;
return;
}
=head2 $filter->filter($resource)
Must be implemented by filter implementations. Returns
true if the filter passes, false otherwise. This method
must B<not> alter the passed-in C<$resource> object.
=head2 $filter->invert()
Returns a filter whose L</filter> method returns the opposite of this filter.
=cut
sub invert {
my ( $self ) = @_;
return App::Ack::Filter::Inverse->new( $self );
}
=head2 $filter->is_inverted()
Returns true if this filter is an inverted filter; false otherwise.
=cut
sub is_inverted {
return 0;
}
=head2 $filter->to_string
Converts the filter to a string. This method is also
called implicitly by stringification.
=cut
sub to_string {
my ( $self ) = @_;
return '(unimplemented to_string)';
}
=head2 $filter->inspect
Prints a human-readable debugging string for this filter. Useful for,
you guessed it, debugging.
=cut
sub inspect {
my ( $self ) = @_;
return ref($self);
}
1;