oracular (3) Attean::SimpleQueryEvaluator.3pm.gz

Provided by: libattean-perl_0.034-1_all bug

NAME
       Attean::SimpleQueryEvaluator - Simple query evaluator


VERSION
       This document describes Attean::SimpleQueryEvaluator version 0.034


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 {}".

       "request_signer"
           If set, used to modify HTTP::Request objects used in evaluating SERVICE calls before the request is
           made. This may be used to, for example, add cryptographic signature headers to the request. The
           modification is performed by calling "$request_signer->sign( $request )".


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 (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.