1Attean::API::Model(3) User Contributed Perl DocumentationAttean::API::Model(3)
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NAME

6       Attean::API::Model - RDF Model
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VERSION

9       This document describes Attean::API::Model version 0.020
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DESCRIPTION

12       The Attean::API::Model role defines a common API for all RDF models to
13       conform to. It is provides a consistent interface for probing,
14       counting, and retrieving Attean::API::Quads matching a pattern, as well
15       as related functionality such as enumerating the graph names, and
16       extracting structured data from the models' quads.
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REQUIRED METHODS

19       The following methods are required by the Attean::API::Model role:
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21       "get_quads( $subject, $predicate, $object, $graph )"
22           Returns an Attean::API::Iterator for quads in the model that match
23           the supplied $subject, $predicate, $object, and $graph.
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25           Any of these terms may be:
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27           * An Attean::API::Term object, in which case matching is equality-
28           based
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30           * A Attean::API::Variable object or "undef", in which case that
31           term will be considered as a wildcard for the purposes of matching
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33           * An ARRAY reference of Attean::API::Term objects, in which case
34           the matching will be equality-based on the disjunction of the
35           supplied terms
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37           The returned iterator conforms to both Attean::API::Iterator and
38           Attean::API::QuadIterator.
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40       "count_quads( $subject, $predicate, $object, $graph )"
41           Returns the number of quads in the model matching the supplied
42           pattern (using the same matching semantics as "get_quads").
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44       "count_quads_estimate( $subject, $predicate, $object, $graph )"
45           Returns an estimate of the number of quads in the model matching
46           the supplied pattern (using the same matching semantics as
47           "get_quads"). This estimate is guaranteed to non-zero if the count
48           returned from an equivalent call to `count_quads` would return a
49           non-zero result.
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51       "get_graphs"
52           Returns an Attean::API::Iterator of distinct Attean::API::Term
53           objects that are used in the graph position of quads in the model.
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METHODS

56       The Attean::API::Model role provides default implementations of the
57       following methods:
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59       "get_bindings( $subject, $predicate, $object, $graph )"
60           Returns an Attean::API::Iterator of Attean::API::Result objects
61           corresponding to quads in the model matching the supplied pattern.
62           For each Attean::API::Variable in the pattern list, a mapping will
63           be present in the corresponding result object. For example,
64           "$model->get_bindings( variable('s') )" will return an iterator of
65           results containing just a mapping from 's' to subjects of all quads
66           in the model.
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68       "get_list( $graph, $head )"
69           Returns an Attean::API::Iterator of Attean::API::Term objects that
70           are members of the rdf:List with the specified $head (and matching
71           restricted to only the specified $graph).
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73       "get_sequence( $graph, $head )"
74           Returns an Attean::API::Iterator of Attean::API::Term objects that
75           are members of the rdf:Sequence with the specified $head (and
76           matching restricted to only the specified $graph).
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78       "subjects( $predicate, $object, $graph )"
79           Returns an Attean::API::Iterator of Attean::API::Term objects of
80           all subjects of quads matching the supplied pattern (using the same
81           matching semantics as "get_quads").
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83       "predicates( $subject, $object, $graph )"
84           Returns an Attean::API::Iterator of Attean::API::Term objects of
85           all predicates of quads matching the supplied pattern (using the
86           same matching semantics as "get_quads" with an "undef" predicate).
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88       "objects( $subject, $predicate, $graph )"
89           Returns an Attean::API::Iterator of Attean::API::Term objects of
90           all objects of quads matching the supplied pattern (using the same
91           matching semantics as "get_quads" with an "undef" object).
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93       "graphs( $subject, $predicate, $object )"
94           Returns an Attean::API::Iterator of Attean::API::Term objects of
95           all graphs of quads matching the supplied pattern (using the same
96           matching semantics as "get_quads" with an "undef" graph).
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98       "graph_nodes( $graph )"
99           Returns an Attean::API::Iterator of Attean::API::Term objects of
100           unique subjects and objects present in the specified $graph.
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BUGS

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

AUTHOR

108       Gregory Todd Williams  "<gwilliams@cpan.org>"
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111       Copyright (c) 2014--2018 Gregory Todd Williams.  This program is free
112       software; you can redistribute it and/or modify it under the same terms
113       as Perl itself.
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117perl v5.28.1                      2019-01-09             Attean::API::Model(3)
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