/usr/share/perl5/RDF/Query/Expression.pm is in librdf-query-perl 2.918-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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# -----------------------------------------------------------------------------
=head1 NAME
RDF::Query::Expression - Class for Expr expressions
=head1 VERSION
This document describes RDF::Query::Expression version 2.918.
=cut
package RDF::Query::Expression;
use strict;
use warnings;
no warnings 'redefine';
use base qw(RDF::Query::Algebra);
use Data::Dumper;
use Scalar::Util qw(blessed);
use Carp qw(carp croak confess);
######################################################################
our ($VERSION);
BEGIN {
$VERSION = '2.918';
}
######################################################################
=head1 METHODS
=over 4
=cut
=item C<new ( $op, @operands )>
Returns a new Expr structure.
=cut
sub new {
my $class = shift;
my $op = shift;
my @operands = @_;
return bless( [ $op, @operands ], $class );
}
=item C<< construct_args >>
Returns a list of arguments that, passed to this class' constructor,
will produce a clone of this algebra pattern.
=cut
sub construct_args {
my $self = shift;
return ($self->op, $self->operands);
}
=item C<< op >>
Returns the operator of the expression.
=cut
sub op {
my $self = shift;
return $self->[0];
}
=item C<< operands >>
Returns a list of the operands of the expression.
=cut
sub operands {
my $self = shift;
return @{ $self }[ 1 .. $#{ $self } ];
}
=item C<< sse >>
Returns the SSE string for this algebra expression.
=cut
sub sse {
my $self = shift;
my $context = shift;
return sprintf(
'(%s %s)',
$self->op,
join(' ', map { $_->sse( $context ) } $self->operands),
);
}
=item C<< explain >>
Returns a string serialization of the expression appropriate for display on the
command line. This method is primarily used by the C<< explain >> method of
the subclasses of RDF::Query::Plan.
=cut
sub explain {
my $self = shift;
my $s = shift;
my $count = shift;
my $indent = $s x $count;
my $type = $self->op;
my $string = "${indent}${type}\n";
foreach my $p ($self->operands) {
if ($p->can('explain')) {
$string .= $p->explain( $s, $count+1 );
} else {
$string .= $p->sse;
}
}
return $string;
}
=item C<< as_hash >>
Returns the expression as a nested set of plain data structures (no objects).
=cut
sub as_hash {
my $self = shift;
my $context = shift;
return {
type => 'expression',
operator => $self->op,
operands => [map { $_->as_hash($context) } $self->operands],
};
}
=item C<< type >>
Returns the type of this algebra expression.
=cut
sub type {
return 'EXPR';
}
=item C<< referenced_variables >>
Returns a list of the variable names used in this algebra expression.
=cut
sub referenced_variables {
my $self = shift;
my @ops = $self->operands;
my @vars;
foreach my $o (@ops) {
if ($o->isa('RDF::Query::Node::Variable')) {
push(@vars, $o->name);
} elsif ($o->isa('RDF::Query::Expression')) {
push(@vars, $o->referenced_variables);
}
}
return RDF::Query::_uniq(@vars);
}
=item C<< nonaggregated_referenced_variables >>
Returns a list of the variable names used in this algebra expression except
those used as aliases for aggregate operations.
=cut
sub nonaggregated_referenced_variables {
my $self = shift;
my @ops = $self->operands;
my @vars;
foreach my $o (@ops) {
if ($o->isa('RDF::Query::Node::Variable::ExpressionProxy')) {
} elsif ($o->isa('RDF::Query::Node::Variable')) {
push(@vars, $o->name);
} elsif ($o->isa('RDF::Query::Expression')) {
push(@vars, $o->nonaggregated_referenced_variables);
}
}
return RDF::Query::_uniq(@vars);
}
1;
__END__
=back
=head1 AUTHOR
Gregory Todd Williams <gwilliams@cpan.org>
=cut
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