/
Nil.pm
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/
Nil.pm
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#!/usr/bin/perl
package Data::Stream::Bulk::Nil;
use Moose;
use namespace::clean -except => 'meta';
with qw(Data::Stream::Bulk) => { excludes => [qw/loaded filter list_cat all items/] };
sub items { return () }
sub all { return () }
sub next { undef }
sub is_done { 1 }
sub list_cat {
my ( $self, $head, @rest ) = @_;
return () unless $head;
return $head->list_cat(@rest);
}
sub filter { return $_[0] };
sub loaded { 1 }
__PACKAGE__->meta->make_immutable;
__PACKAGE__
__END__
=pod
=head1 NAME
Data::Stream::Bulk::Nil - An empty L<Data::Stream::Bulk> iterator
=head1 SYNOPSIS
return Data::Stream::Bulk::Nil->new; # empty set
=head1 DESCRIPTION
This iterator can be used to return the empty resultset.
=head1 METHODS
=over 4
=item is_done
Always returns true.
=item next
Always returns undef.
=item items
=item all
Always returns the empty list.
=item list_cat
Skips $self
=item filter
Returns $self
=item loaded
Returns true.
=back
=cut