1Attean::SimpleQueryEvalUusaetrorC(o3n)tributed Perl DocuAmtetnetaant:i:oSnimpleQueryEvaluator(3)
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6 Attean::SimpleQueryEvaluator - Simple query evaluator
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9 This document describes Attean::SimpleQueryEvaluator version 0.033
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12 use v5.14;
13 use Attean;
14 my $algebra = Attean->get_parser('SPARQL')->parse('SELECT * WHERE { ... }');
15 my $active_graph = Attean::IRI->new('http://example.org/');
16 my $e = Attean::SimpleQueryEvaluator->new( model => $model );
17 my $iter = $e->evaluate( $algebra, $active_graph );
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20 The Attean::SimpleQueryEvaluator class implements a simple query
21 evaluator that, given an Attean::API::Algebra and a Attean::API::Model
22 object, evaluates the query represented by the algebra using data from
23 the model, and returns a query result.
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26 "model"
27 The Attean::API::Model object used for query evaluation.
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29 "default_graph"
30 The Attean::API::IRI object representing the default graph in the
31 "model". The default graph will be excluded from enumeration of
32 graph names for query features such as "GRAPH ?g {}".
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34 "request_signer"
35 If set, used to modify HTTP::Request objects used in evaluating
36 SERVICE calls before the request is made. This may be used to, for
37 example, add cryptographic signature headers to the request. The
38 modification is performed by calling "$request_signer->sign(
39 $request )".
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42 "evaluate( $algebra, $active_graph )"
43 Returns an Attean::API::Iterator object with results produced by
44 evaluating the query $algebra against the evaluator's "model",
45 using the supplied $active_graph.
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47 "evaluate_pattern( $pattern, $active_graph, \@new_vars, \%blanks )"
48 Returns an Attean::API::Iterator object with results produced by
49 evaluating the triple- or quad-pattern $pattern against the
50 evaluator's "model", using the supplied $active_graph.
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52 If the "ground_blanks" option is false, replaces blank nodes in the
53 pattern with fresh variables before evaluation, and populates
54 %blanks with pairs ($variable_name => $variable_node). Each new
55 variable is also appended to @new_vars as it is created.
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58 Please report any bugs or feature requests to through the GitHub web
59 interface at <https://github.com/kasei/attean/issues>.
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63 Gregory Todd Williams "<gwilliams@cpan.org>"
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66 Copyright (c) 2014--2022 Gregory Todd Williams. This program is free
67 software; you can redistribute it and/or modify it under the same terms
68 as Perl itself.
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72perl v5.36.0 2022-10-03 Attean::SimpleQueryEvaluator(3)