/* $Id$
Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: wielemak@science.uva.nl
WWW: http://www.swi-prolog.org
Copyright (C): 1985-2005, University of Amsterdam
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
As a special exception, if you link this library with other files,
compiled with a Free Software compiler, to produce an executable, this
library does not by itself cause the resulting executable to be covered
by the GNU General Public License. This exception does not however
invalidate any other reasons why the executable file might be covered by
the GNU General Public License.
*/
:- module(rdfs,
[ rdfs_subproperty_of/2, % ?SubProperties, ?Property
rdfs_subclass_of/2, % ?SubClass, ?Class
rdfs_class_property/2, % +Class, ?Property
rdfs_individual_of/2, % ?Resource, ?Class
rdfs_label/2, % ?Resource, ?Label
rdfs_label/3, % ?Resource, ?Language, ?Label
rdfs_ns_label/2, % +Resource, -Label
rdfs_ns_label/3, % +Resource, ?Label, -Label
rdfs_member/2, % ?Object, +Set
rdfs_list_to_prolog_list/2, % +Set, -List
rdfs_assert_list/3, % +List, -Resource, +DB
rdfs_assert_list/2, % +List, -Resource
rdfs_find/5 % +String, +Dom, +Props, +Method, -Subj
]).
:- use_module(library(debug)).
:- use_module(library(rdf)).
:- use_module(library(lists)).
:- use_module(rdf_db).
/** <module> RDFS handling
This module provides various primitives for more high-level handling of
RDF models from an RDFS viewpoint. Note that there exist two approaches
for languages on top of RDF:
* Provide new predicates according to the concept of the high
level language (used in this module)
* Extend rdf/3 relation with triples _implied_ by the high-level
semantics. This approach is taken by the SeRQL system.
*/
/*******************************
* EXPANSION *
*******************************/
:- rdf_meta
rdfs_subproperty_of(r,r),
rdfs_subclass_of(r,r),
rdfs_class_property(r,r),
rdfs_individual_of(r,r),
rdfs_label(r,-).
/*******************************
* PROPERTY HIERARCHY *
*******************************/
%% rdfs_subproperty_of(+SubProperty, ?Property) is nondet.
%% rdfs_subproperty_of(?SubProperty, +Property) is nondet.
%
% Query the property hierarchy.
rdfs_subproperty_of(SubProperty, Property) :-
rdf_reachable(SubProperty, rdfs:subPropertyOf, Property).
/*******************************
* CLASS HIERARCHY *
*******************************/
%% rdfs_subclass_of(+Class, ?Super) is nondet.
%% rdfs_subclass_of(?Class, +Super) is nondet.
%
% Generate sub/super classes. rdf_reachable/3 considers the
% rdfs:subPropertyOf relation as well as cycles. Note that by
% definition all classes are subclass of rdfs:Resource, a case
% which is dealt with by the 1st and 3th clauses :-(
%
% According to production 2.4 "rdfs:Datatype", Each instance of
% rdfs:Datatype is a subclass of rdfs:Literal.
rdfs_subclass_of(Class, Super) :-
rdf_equal(rdfs:'Resource', Resource),
Super == Resource, !,
( nonvar(Class)
-> true % must check for being a class?
; rdfs_individual_of(Class, rdfs:'Class')
).
rdfs_subclass_of(Class, Super) :-
rdf_reachable(Class, rdfs:subClassOf, Super).
rdfs_subclass_of(Class, Super) :-
nonvar(Class),
var(Super),
\+ rdf_reachable(Class, rdfs:subClassOf, rdfs:'Resource'),
rdfs_individual_of(Class, rdfs:'Class'),
rdf_equal(Super, rdfs:'Resource').
rdfs_subclass_of(Class, Super) :- % production 2.4
( nonvar(Class)
-> rdf_has(Class, rdf:type, CType),
rdf_reachable(CType, rdfs:subClassOf, rdfs:'Datatype'),
\+ rdf_reachable(Class, rdfs:subClassOf, rdfs:'Literal'),
rdf_equal(Super, rdfs:'Literal')
; nonvar(Super)
-> rdf_reachable(Super, rdfs:subClassOf, rdfs:'Literal'),
rdfs_individual_of(Class, rdfs:'Datatype')
).
/*******************************
* INDIVIDUALS *
*******************************/
%% rdfs_individual_of(+Resource, +Class) is semidet.
%% rdfs_individual_of(+Resource, -Class) is nondet.
%% rdfs_individual_of(-Resource, +Class) is nondet.
%
% Generate resources belonging to a class or classes a resource
% belongs to. We assume everything at the `object' end of a triple
% is a class. A validator should confirm this property.
%
% rdfs_individual_of(+, -) does not exploit domain and range
% properties, deriving that if rdf(R, P, _) is present R must
% satisfy the domain of P (and similar for range).
%
% There are a few hacks:
%
% * Any resource is an individual of rdfs:Resource
% * literal(_) is an individual of rdfs:Literal
rdfs_individual_of(Resource, Class) :-
nonvar(Resource), !,
( nonvar(Class)
-> ( rdfs_individual_of_r_c(Resource, Class)
-> true
)
; rdfs_individual_of_r_c(Resource, Class)
).
rdfs_individual_of(Resource, Class) :-
nonvar(Class), !,
( rdf_equal(Class, rdfs:'Resource')
-> rdf_subject(Resource)
; rdfs_subclass_of(SubClass, Class),
rdf_has(Resource, rdf:type, SubClass)
).
rdfs_individual_of(_Resource, _Class) :-
throw(error(instantiation_error, _)).
rdfs_individual_of_r_c(literal(_), Class) :- !,
rdfs_subclass_of(Class, rdfs:'Literal').
rdfs_individual_of_r_c(Resource, Class) :-
rdf_has(Resource, rdf:type, MyClass),
rdfs_subclass_of(MyClass, Class).
rdfs_individual_of_r_c(_, Class) :-
rdf_equal(Class, rdfs:'Resource').
%% rdfs_label(+Resource, -Label).
%% rdfs_label(-Resource, +Label).
%
% Convert between class and label. If the label is generated from
% the resource the it uses both rdf:label and its sub-properties,
% but labels registered with rdf:label are returned first.
rdfs_label(Resource, Label) :-
rdfs_label(Resource, _, Label).
%% rdfs_label(+Resource, ?Lang, -Label) is multi.
%% rdfs_label(+Resource, ?Lang, +Label) is semidet.
%% rdfs_label(-Resource, ?Lang, ?Label) is nondet.
%
% Resource has Label in Lang. If Resource is nonvar calls
% take_label/3 which is guaranteed to succeed label.
rdfs_label(Resource, Lang, Label) :-
nonvar(Resource), !,
take_label(Resource, Lang, Label).
rdfs_label(Resource, Lang, Label) :-
rdf_has(Resource, rdfs:label, literal(lang(Lang, Label))).
%% rdfs_ns_label(+Resource, -Label) is multi.
%% rdfs_ns_label(+Resource, ?Lang, -Label) is multi.
%
% Present label with namespace indication. This predicate is
% indented to provide meaningful short names applicable to
% ontology maintainers. Note that this predicate is non-deterministic
% if the resource has multiple rdfs:label properties
rdfs_ns_label(Resource, Label) :-
rdfs_ns_label(Resource, _, Label).
rdfs_ns_label(Resource, Lang, Label) :-
rdfs_label(Resource, Lang, Label0),
( rdf_global_id(NS:_, Resource),
Label0 \== ''
-> atomic_list_concat([NS, Label0], :, Label)
; \+ rdf_has(Resource, rdfs:label, _)
-> Label = Resource
; member(Sep, [#,/]),
sub_atom(Resource, B, L, A, Sep),
sub_atom(Resource, _, A, 0, Frag),
\+ sub_atom(Frag, _, _, _, Sep)
-> Len is B+L,
sub_atom(Resource, 0, Len, _, NS),
atomic_list_concat([NS, Label0], :, Label)
; Label = Label0
).
%% take_label(+Resource, ?Lang, -Label) is multi.
%
% Get the label to use for a resource in the give Language. First
% tries label_of/3. If this fails, break the Resource over # or /
% and if all fails, unify Label with Resource.
take_label(Resource, Lang, Label) :-
( label_of(Resource, Lang, Label)
*-> true
; after_char(Resource, '#', Local)
-> Label = Local
; after_char(Resource, '/', Local)
-> Label = Local
; Label = Resource
).
after_char(Atom, Char, Rest) :-
State = last(-),
( sub_atom(Atom, _, _, L, Char),
nb_setarg(1, State, L),
fail
; arg(1, State, L),
L \== (-)
),
sub_atom(Atom, _, L, 0, Rest).
%% label_of(+Resource, ?Lang, ?Label) is nondet.
%
% True if rdf_has(Resource, rdfs:label, literal(Lang, Label)) is
% true, but guaranteed to generate rdfs:label before any
% subproperty thereof.
label_of(Resource, Lang, Label) :-
rdf(Resource, rdfs:label, literal(lang(Lang, Label))).
label_of(Resource, Lang, Label) :-
rdf_equal(rdfs:label, LabelP),
rdf_has(Resource, LabelP, literal(lang(Lang, Label)), P),
P \== LabelP.
%% rdfs_class_property(+Class, ?Property)
%
% Enumerate the properties in the domain of Class.
rdfs_class_property(Class, Property) :-
rdfs_individual_of(Property, rdf:'Property'),
rdf_has(Property, rdfs:domain, Domain),
rdfs_subclass_of(Class, Domain).
/*******************************
* COLLECTIONS *
*******************************/
%% rdfs_member(?Element, +Set)
%
% As Prolog member on sets. Operates both on attributes parsed as
% parseType="Collection" as well as on Bag, Set and Alt.
rdfs_member(Element, Set) :-
rdf_has(Set, rdf:first, _),
rdfs_collection_member(Element, Set).
rdfs_member(Element, Set) :-
rdfs_individual_of(Set, rdfs:'Container'), !,
( nonvar(Element)
-> rdf(Set, Predicate, Element),
rdf_member_property(Predicate, _N)
; between(1, infinite, N),
rdf_member_property(Prop, N),
( rdf(Set, Prop, Member)
-> Member = Element
; !, fail
)
).
rdfs_collection_member(Element, Set) :-
rdf_has(Set, rdf:first, Element).
rdfs_collection_member(Element, Set) :-
rdf_has(Set, rdf:rest, Tail), !,
rdfs_collection_member(Element, Tail).
%% rdfs_list_to_prolog_list(+RDFSList, -PrologList)
%
% Convert ann RDFS list (result from parseType=Collection) into a
% Prolog list of elements.
rdfs_list_to_prolog_list(Set, []) :-
rdf_equal(Set, rdf:nil), !.
rdfs_list_to_prolog_list(Set, [H|T]) :-
rdf_has(Set, rdf:first, H),
rdf_has(Set, rdf:rest, Tail), !,
rdfs_list_to_prolog_list(Tail, T).
%% rdfs_assert_list(+Resources, -List) is det.
%% rdfs_assert_list(+Resources, -List, +DB) is det.
%
% Create an RDF list from the given Resources.
rdfs_assert_list(Resources, List) :-
rdfs_assert_list(Resources, List, user).
rdfs_assert_list([], Nil, _) :-
rdf_equal(rdf:nil, Nil).
rdfs_assert_list([H|T], List, DB) :-
rdfs_assert_list(T, Tail, DB),
rdf_bnode(List),
rdf_assert(List, rdf:rest, Tail, DB),
rdf_assert(List, rdf:first, H, DB),
rdf_assert(List, rdf:type, rdf:'List', DB).
/*******************************
* SEARCH IN HIERARCHY *
*******************************/
%% rdfs_find(+String, +Domain, ?Properties, +Method, -Subject)
%
% Search all classes below Domain for a literal property with
% that matches String. Method is one of
%
% * substring
% * word
% * prefix
% * exact
%
% domain is defined by owl_satisfy from owl.pl
%
% Note that the rdfs:label field is handled by rdfs_label/2,
% making the URI-ref fragment name the last resort to determine
% the label.
rdfs_find(String, Domain, Fields, Method, Subject) :-
var(Fields), !,
For =.. [Method,String],
rdf_has(Subject, Field, literal(For, _)),
owl_satisfies(Domain, Subject),
Fields = [Field]. % report where we found it.
rdfs_find(String, Domain, Fields, Method, Subject) :-
globalise_list(Fields, GlobalFields),
For =.. [Method,String],
member(Field, GlobalFields),
( Field == resource
-> rdf_subject(Subject),
rdf_match_label(Method, String, Subject)
; rdf_has(Subject, Field, literal(For, _))
),
owl_satisfies(Domain, Subject).
owl_satisfies(Domain, _) :-
rdf_equal(rdfs:'Resource', Domain), !.
% Descriptions
owl_satisfies(class(Domain), Resource) :- !,
( rdf_equal(Domain, rdfs:'Resource')
-> true
; rdfs_subclass_of(Resource, Domain)
).
owl_satisfies(union_of(Domains), Resource) :- !,
member(Domain, Domains),
owl_satisfies(Domain, Resource), !.
owl_satisfies(intersection_of(Domains), Resource) :- !,
in_all_domains(Domains, Resource).
owl_satisfies(complement_of(Domain), Resource) :- !,
\+ owl_satisfies(Domain, Resource).
owl_satisfies(one_of(List), Resource) :- !,
memberchk(Resource, List).
% Restrictions
owl_satisfies(all_values_from(Domain), Resource) :-
( rdf_equal(Domain, rdfs:'Resource')
-> true
; rdfs_individual_of(Resource, Domain)
), !.
owl_satisfies(some_values_from(_Domain), _Resource) :- !.
owl_satisfies(has_value(Value), Resource) :-
rdf_equal(Value, Resource).
in_all_domains([], _).
in_all_domains([H|T], Resource) :-
owl_satisfies(H, Resource),
in_all_domains(T, Resource).
globalise_list([], []) :- !.
globalise_list([H0|T0], [H|T]) :- !,
globalise_list(H0, H),
globalise_list(T0, T).
globalise_list(X, G) :-
rdf_global_id(X, G).
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
TOP-DOWN
rdfs_find(String, Domain, Fields, Method, Subject) :-
globalise_list(Fields, GlobalFields),
generate_domain(Domain, Subject),
member(Field, GlobalFields),
( rdf_equal(Field, rdfs:label)
-> rdfs_label(Subject, Arg)
; rdf_has(Subject, Field, literal(Arg))
),
rdf_match_label(Method, String, Arg).
%% generate_domain(+Domain, -Resource)
%
% Generate all resources that satisfy some a domain specification.
generate_domain(All, Subject) :-
rdf_equal(All, rdfs:'Resource'), !,
rdf_subject(Subject).
generate_domain(class(Class), Subject) :- !,
rdfs_subclass_of(Subject, Class).
generate_domain(all_values_from(Class), Individual) :-
( rdf_equal(Class, rdfs:'Resource')
-> rdf_subject(Individual) % this is OWL-full
; rdfs_individual_of(Individual, Class)
).
generate_domain(some_values_from(Class), Individual) :- % Actually this is
rdfs_individual_of(Individual, Class). % anything
generate_domain(union_of(Domains), Individual) :-
member(Domain, Domains),
generate_domain(Domain, Individual).
generate_domain(intersection_of(Domains), Individual) :-
in_all_domains(Domains, Individual).
generate_domain(one_of(Individuals), Individual) :-
member(Individual, Individuals).
in_all_domains([], _).
in_all_domains([H|T], Resource) :-
generate_domain(H, Resource),
in_all_domains(T, Resource).
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */