RDF::Query::Algebra - Base class for Algebra expressions


This document describes RDF::Query::Algebra version 2.918.



Returns a list of the variable names used in this algebra expression that will bind values during execution.


Returns a list of the blank node names used in this algebra expression.


Returns a list of the Function URIs used in this algebra expression.


Returns true if blank nodes respect the SPARQL rule of no blank-label re-use across BGPs, otherwise throws a RDF::Query::Error::QueryPatternError exception.

qualify_uris ( \%namespaces, $base_uri )

Returns a new algebra pattern where all referenced Resource nodes representing QNames (ns:local) are qualified using the supplied %namespaces.

bind_variables ( \%bound )

Returns a new algebra pattern with variables named in %bound replaced by their corresponding bound values.


Returns true if this node is a solution modifier.

subpatterns_of_type ( $type [, $block] )

Returns a list of Algebra patterns matching $type (tested with isa). If $block is given, then matching stops descending a subtree if the current node is of type $block, continuing matching on other subtrees. This list includes the current algebra object if it matches $type, and is generated in infix order.

from_sse ( $sse, \%context )

Given an SSE serialization, returns the corresponding algebra expression.


triple ( $subj, $pred, $obj )

Returns a RDF::Query::Algebra::Triple object with the supplied node objects.

bgp ( @triples )

Returns a RDF::Query::Algebra::BasicGraphPattern object with the supplied triples.

ggp ( @patterns )

Returns a RDF::Query::Algebra::GroupGraphPattern object with the supplied algebra patterns.


 Gregory Todd Williams <>