/* Part of SWI-Prolog Author: Jan Wielemaker and Wouter Beek E-mail: J.Wielemaker@vu.nl WWW: http://www.swi-prolog.org Copyright (c) 2016, VU University Amsterdam All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ :- module(rdf11_containers, [ rdf_alt/3, % ?Alt, -Default, -Others rdf_assert_alt/3, % ?Alt, +Default, +Others rdf_assert_alt/4, % ?Alt, +Default, +Others, +G rdf_assert_bag/2, % ?Bag, +Set rdf_assert_bag/3, % ?Bag, +Set, +G rdf_assert_seq/2, % ?Seq, +List rdf_assert_seq/3, % ?Seq, +List, +G rdf_bag/2, % ?Bag, -List rdf_seq/2, % ?Seq, -List rdfs_container/2, % ?Container, -List rdfs_container_membership_property/1, % ?Property rdfs_container_membership_property/2, % ?Property, ?Number rdfs_member/2, % ?Elem, ?Container rdfs_nth0/3 % ?N, ?Container, ?Elem ]). :- use_module(library(semweb/rdf_prefixes), [ (rdf_meta)/1, op(_,_,rdf_meta) ]). :- use_module(rdf11, [ rdf_default_graph/1, rdf_transaction/1, rdf_create_bnode/1, rdf_assert/4, rdf_equal/2, rdf_is_subject/1, rdf_has/3 ]). :- autoload(library(apply),[maplist/3]). :- autoload(library(error),[must_be/2,type_error/2]). :- autoload(library(lists),[member/2]). :- autoload(library(pairs),[group_pairs_by_key/2,pairs_values/2]). /** RDF 1.1 Containers Implementation of the conventional human interpretation of RDF 1.1 containers. RDF containers are open enumeration structures as opposed to RDF collections or RDF lists which are closed enumeration structures. The same resource may appear in a container more than once. A container may be contained in itself. --- @author Wouter Beek @author Jan Wielemaker @compat RDF 1.1 @see http://www.w3.org/TR/2014/REC-rdf-schema-20140225/#ch_containervocab @version 2016/01 */ :- rdf_meta rdf_alt(r, -, -), rdf_assert_alt(r, r, t), rdf_assert_alt(r, r, t, r), rdf_assert_bag(r, t), rdf_assert_bag(r, t, r), rdf_assert_seq(r, t), rdf_assert_seq(r, t, r), rdf_bag(r, -), rdf_seq(r, -), rdfs_assert_container(r, t), rdfs_assert_container(r, t, r), rdfs_assert_container(r, r, t, r), rdfs_container(r, -), rdfs_container_membership_property(r), rdfs_container_membership_property(r,?), rdfs_member(r, -). %! rdf_alt(+Alt, ?Default, ?Others) is nondet. % % True when Alt is an instance of `rdf:Alt` with first member % Default and remaining members Others. % % Notice that this construct adds no machine-processable semantics % but is conventionally used to indicate to a human reader that % the numerical ordering of the container membership properties of % Container is intended to only be relevant in distinguishing % between the first and all non-first members. % % Default denotes the default option to take when choosing one of % the alternatives container in Container. Others denotes the % non-default options that can be chosen from. rdf_alt(Alt, Default, Others) :- rdfs_container(Alt, [Default|Others]). %! rdf_assert_alt(?Alt, +Default, +Others:list) is det. %! rdf_assert_alt(?Alt, +Default, +Others:list, +Graph) is det. % % Create an rdf:Alt with the given Default and Others. Default and % the members of Others must be valid object terms for % rdf_assert/3. rdf_assert_alt(Alt, H, T) :- rdf_default_graph(G), rdf_assert_alt(Alt, H, T, G). rdf_assert_alt(Alt, H, T, G) :- rdfs_assert_container(Alt, rdf:'Alt', [H|T], G). %! rdf_bag(+Bag, -List:list) is nondet. % % True when Bag is an rdf:Bag and set is the set values related % through container membership properties to Bag. % % Notice that this construct adds no machine-processable semantics % but is conventionally used to indicate to a human reader that % the numerical ordering of the container membership properties of % Container is intended to not be significant. rdf_bag(Bag, List) :- rdfs_container(Bag, List). %! rdf_assert_bag(?Bag, +Set:list) is det. %! rdf_assert_bag(?Bag, +Set:list, +Graph) is det. % % Create an rdf:Bag from the given set of values. The members of % Set must be valid object terms for rdf_assert/3. rdf_assert_bag(Bag, L) :- rdf_default_graph(G), rdf_assert_bag(Bag, L, G). rdf_assert_bag(Bag, L, G) :- rdfs_assert_container(Bag, rdf:'Bag', L, G). %! rdf_seq(+Seq, -List:list) is nondet. % % True when Seq is an instance of rdf:Seq and List is a list of % associated values, ordered according to the container membership % property used. % % Notice that this construct adds no machine-processable semantics % but is conventionally used to indicate to a human reader that % the numerical ordering of the container membership properties of % Container is intended to be significant. rdf_seq(Seq, L) :- rdfs_container(Seq, L). %! rdf_assert_seq(?Seq, +List) is det. %! rdf_assert_seq(?Seq, +List, +Graph) is det. rdf_assert_seq(Seq, L) :- rdf_default_graph(G), rdf_assert_seq(Seq, L, G). rdf_assert_seq(Seq, L, G) :- rdfs_assert_container(Seq, rdf:'Seq', L, G). %! rdfs_assert_container(?Container, +Class, +Elems, +Graph) rdfs_assert_container(Container, Class, Elems, G) :- must_be(list, Elems), rdf_transaction(rdfs_assert_container_(Container, Class, Elems, G)). rdfs_assert_container_(Container, Class, Elems, G) :- (var(Container) -> rdf_create_bnode(Container) ; true), rdf_assert(Container, rdf:type, Class, G), rdfs_assert_members(Elems, 1, Container, G). rdfs_assert_members([], _, _, _). rdfs_assert_members([H|T], N1, Resource, G) :- !, rdf_equal(rdf:'_', Prefix), atom_concat(Prefix, N1, P), rdf_assert(Resource, P, H, G), N2 is N1 + 1, rdfs_assert_members(T, N2, Resource, G). %! rdfs_container(+Container, -List) is nondet. % % True when List is the list of objects attached to Container % using a container membership property (rdf:_0, rdf:_1, ...). If % multiple objects are connected to the Container using the same % membership property, this predicate selects one value % non-deterministically. rdfs_container(Container, List) :- rdf_is_subject(Container), !, findall(N-Elem, rdfs_member0(Container, N, Elem), Pairs), keysort(Pairs, Sorted), group_pairs_by_key(Sorted, GroupedPairs), pairs_values(GroupedPairs, Groups), maplist(member, List, Groups). rdfs_container(Container, _) :- type_error(rdf_subject, Container). %! rdfs_container_membership_property(?Property) is nondet. % % True when Property is a container membership property (rdf:_1, % rdf:_2, ...). rdfs_container_membership_property(P) :- rdfs_container_membership_property(P, _). %! rdfs_container_membership_property(?Property, ?Number:nonneg) is nondet. % % True when Property is the Nth container membership property. % % Success of this goal does not imply that Property is present % in the database. rdfs_container_membership_property(P, N) :- var(P), !, between(1, inf, N), rdf_equal(rdf:'_', Prefix), atom_concat(Prefix, N, P). rdfs_container_membership_property(P, N) :- atom(P), rdf_equal(rdf:'_', Prefix), string_concat(Prefix, NumS, P), number_string(N, NumS), integer(N), N >= 0. %! rdfs_member(?Elem, ?Container) is nondet. % % True if rdf(Container, P, Elem) is true and P is a container % membership property. rdfs_member(Elem, Container) :- rdfs_member0(Container, _, Elem). %! rdfs_nth0(?N, ?Container, ?Elem) is nondet. % % True if rdf(Container, P, Elem) is true and P is the N-th % (0-based) container membership property. rdfs_nth0(N, Container, Elem) :- rdfs_member0(Container, N, Elem). %! rdfs_member0(?Container, ?N, ?Elem) is nondet. % % What is the most efficient way to enumerate rdfs_member(-,-)? % % 1. If we enumerate over all container membership properties (= the % current implementation) then it takes N steps before we get to % triple ``, for arbitrary N. % % 2. The alternative is to enumerate over all triples and check % whether the predicate term is a container membership property. % % 3. The choice between (1) and (2) depends on whether the number of % currently loaded triples in larger/smaller than the largest number % that appears in a container membership property. This means % enumerating over all predicate terms using rdf_predicate/1. rdfs_member0(Container, N, Elem) :- (nonvar(Container) ; nonvar(Elem)), !, rdf_has(Container, P, Elem), rdfs_container_membership_property(P, N). rdfs_member0(Container, N, Elem) :- rdfs_container_membership_property(P, N), rdf_has(Container, P, Elem).