NAME

       Attean::SimpleQueryEvaluator - Simple query evaluator

VERSION

       This document describes Attean::SimpleQueryEvaluator version 0.032

SYNOPSIS

         use v5.14;
         use Attean;
         my $algebra = Attean->get_parser('SPARQL')->parse('SELECT * WHERE { ... }');
         my $active_graph = Attean::IRI->new('http://example.org/');
         my $e = Attean::SimpleQueryEvaluator->new( model => $model );
         my $iter = $e->evaluate( $algebra, $active_graph );

DESCRIPTION

       The Attean::SimpleQueryEvaluator class implements a simple query evaluator that, given an
       Attean::API::Algebra and a Attean::API::Model object, evaluates the query represented by
       the algebra using data from the model, and returns a query result.

ATTRIBUTES

       "model"
           The Attean::API::Model object used for query evaluation.

       "default_graph"
           The Attean::API::IRI object representing the default graph in the "model".  The
           default graph will be excluded from enumeration of graph names for query features such
           as "GRAPH ?g {}".

METHODS

       "evaluate( $algebra, $active_graph )"
           Returns an Attean::API::Iterator object with results produced by evaluating the query
           $algebra against the evaluator's "model", using the supplied $active_graph.

       "evaluate_pattern( $pattern, $active_graph, \@new_vars, \%blanks )"
           Returns an Attean::API::Iterator object with results produced by evaluating the
           triple- or quad-pattern $pattern against the evaluator's "model", using the supplied
           $active_graph.

           If the "ground_blanks" option is false, replaces blank nodes in the pattern with fresh
           variables before evaluation, and populates %blanks with pairs ($variable_name =>
           $variable_node). Each new variable is also appended to @new_vars as it is created.

BUGS

       Please report any bugs or feature requests to through the GitHub web interface at
       <https://github.com/kasei/attean/issues>.

SEE ALSO

AUTHOR

       Gregory Todd Williams  "<gwilliams@cpan.org>"

COPYRIGHT

       Copyright (c) 2014--2022 Gregory Todd Williams.  This program is free software; you can
       redistribute it and/or modify it under the same terms as Perl itself.