Mercurial > hg > dbtune-rdf-services
view jamendo/sparql-archived/SeRQL/sparql_runtime.pl @ 27:d95e683fbd35 tip
Enable CORS on urispace redirects as well
author | Chris Cannam |
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date | Tue, 20 Feb 2018 14:52:02 +0000 |
parents | df9685986338 |
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/* $Id$ Part of SWI-Prolog Author: Jan Wielemaker E-mail: wielemak@science.uva.nl WWW: http://www.swi-prolog.org Copyright (C): 2004-2006, 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(sparql_runtime, [ sparql_true/1, sparql_eval/2 ]). :- use_module(library('semweb/rdf_db')). :- use_module(library(xsdp_types)). :- discontiguous term_expansion/2. %% sparql_true(+Term) % % Generated from FILTER Term, where Term must be converted to a % boolean as 'Effective Boolean Value'. sparql_true(Term) :- !, typed_eval(boolean, Term, Result), Result = boolean(true). %% eval(+Term, -Result) eval(Var, unbound(Var)) :- var(Var), !. eval(literal(Literal), Result) :- !, eval_literal(Literal, Result). eval(Atom, iri(Atom)) :- atom(Atom), !. eval(Term, Result) :- sparql_op(Term, Types), !, Term =.. [Op|Args0], eval_args(Args0, Types, Args), EvalTerm =.. [Op|Args], op(EvalTerm, Result). eval(function(Term), Result) :- !, ( xsd_cast(Term, Type, Value) -> eval_cast(Type, Value, Result) ; eval_function(Term, Result) ). eval(Term, Term). % Result of sub-eval eval_args([], [], []). eval_args([H0|T0], [Type0|Types], [H|T]) :- ( typed_eval(Type0, H0, H) -> true ; H = boolean(error) ), eval_args(T0, Types, T). %% eval(+Type, +Term, -Result) % % Evaluate Term, converting the resulting argument to Type. typed_eval(no_eval, Term, Term). typed_eval(any, Term, Result) :- eval(Term, Result). typed_eval(simple_literal, Term, Result) :- eval(Term, Result). typed_eval(boolean, Term, Result) :- eval(Term, Result0), effective_boolean_value(Result0, Result). typed_eval(numeric, Term, Result) :- eval(Term, Eval), ( Eval = numeric(_,_) -> Result = Eval ; throw(error(type_error(numeric, Result), _)) ). eval_literal(type(Type, Atom), Value) :- !, eval_typed_literal(Type, Atom, Value). eval_literal(lang(Lang, Atom), lang(Lang, Atom)) :- !. eval_literal(Atom, simple_literal(Atom)) :- atom(Atom), !. eval_typed_literal(Type, Atom, numeric(Type, Value)) :- xsdp_numeric_uri(Type, _), !, to_number(Atom, Value). eval_typed_literal(Type, Atom, boolean(Atom)) :- rdf_equal(Type, xsd:boolean), !. eval_typed_literal(Type, Atom, date_time(Atom)) :- rdf_equal(Type, xsd:dateTime), !. eval_typed_literal(Type, Atom, typed_literal(Type, Atom)). %% to_number(+NumberOrAtom, -Number) % % Dubious. Comes from grammar that translates 15 into %% literal(type(xsd:integer, 15)). to_number(N, N) :- number(N), !. to_number(A, N) :- atom_number(A, N). %% op(+Operator, -Result) is semidet. % % @param Operator Term of the format Op(Arg...) where each Arg % is embedded in its type. % @param Result Result-value, embedded in its type. % SPARQL Unary operators op(not(boolean(X)), boolean(Result)) :- not(X, Result). op(+(numeric(Type, X)), numeric(Type, X)). op(-(numeric(Type, X)), numeric(Type, Result)) :- Result is -X. % SPARQL Tests, defined in section 11.4 op(bound(X), boolean(Result)) :- (bound(X) -> Result = true ; Result = false). op(isiri(X), boolean(Result)) :- (isiri(X) -> Result = true ; Result = false). op(isuri(X), boolean(Result)) :- (isiri(X) -> Result = true ; Result = false). op(isblank(X), boolean(Result)) :- (isblank(X) -> Result = true ; Result = false). op(isliteral(X), boolean(Result)) :- (isliteral(X) -> Result = true ; Result = false). % SPARQL Accessors op(str(X), simple_literal(Str)) :- str(X, Str). op(lang(X), simple_literal(Lang)) :- lang(X, Lang). op(datatype(X), Type) :- datatype(X, Type). % SPARQL Binary operators % Logical connectives, defined in section 11.4 op(and(boolean(A), boolean(B)), boolean(Result)) :- sparql_and(A, B, Result). op(or(boolean(A), boolean(B)), boolean(Result)) :- sparql_or(A, B, Result). % XPath Tests op(numeric(_, X) = numeric(_, Y), boolean(Result)) :- (X =:= Y -> Result = true ; Result = false). op(date_time(X) = date_time(Y), boolean(Result)) :- (X == Y -> Result = true ; Result = false). op(numeric(_, X) \= numeric(_, Y), boolean(Result)) :- (X =\= Y -> Result = true ; Result = false). op(date_time(X) \= date_time(Y), boolean(Result)) :- (X \== Y -> Result = true ; Result = false). %< op(numeric(_, X) < numeric(_, Y), boolean(Result)) :- (X < Y -> Result = true ; Result = false). op(simple_literal(X) < simple_literal(Y), boolean(Result)) :- (X @< Y -> Result = true ; Result = false). op(string(X) < string(Y), boolean(Result)) :- (X @< Y -> Result = true ; Result = false). op(date_time(X) < date_time(Y), boolean(Result)) :- (X @< Y -> Result = true ; Result = false). %> op(numeric(_, X) > numeric(_, Y), boolean(Result)) :- (X > Y -> Result = true ; Result = false). op(simple_literal(X) > simple_literal(Y), boolean(Result)) :- (X @> Y -> Result = true ; Result = false). op(string(X) > string(Y), boolean(Result)) :- (X @> Y -> Result = true ; Result = false). op(date_time(X) > date_time(Y), boolean(Result)) :- (X @> Y -> Result = true ; Result = false). %=< op(numeric(_, X) =< numeric(_, Y), boolean(Result)) :- (X =< Y -> Result = true ; Result = false). op(simple_literal(X) =< simple_literal(Y), boolean(Result)) :- (X @=< Y -> Result = true ; Result = false). op(string(X) =< string(Y), boolean(Result)) :- (X @=< Y -> Result = true ; Result = false). op(date_time(X) =< date_time(Y), boolean(Result)) :- (X @=< Y -> Result = true ; Result = false). %>= op(numeric(_, X) >= numeric(_, Y), boolean(Result)) :- (X >= Y -> Result = true ; Result = false). op(simple_literal(X) >= simple_literal(Y), boolean(Result)) :- (X @>= Y -> Result = true ; Result = false). op(string(X) >= string(Y), boolean(Result)) :- (X @>= Y -> Result = true ; Result = false). op(date_time(X) >= date_time(Y), boolean(Result)) :- (X @>= Y -> Result = true ; Result = false). op(numeric(TX, X) * numeric(TY, Y), numeric(Type, Result)) :- Result is X * Y, combine_types(TX, TY, Type). op(numeric(TX, X) / numeric(TY, Y), numeric(Type, Result)) :- Result is X / Y, combine_types_div(TX, TY, Type). op(numeric(TX, X) + numeric(TY, Y), numeric(Type, Result)) :- Result is X + Y, combine_types(TX, TY, Type). op(numeric(TX, X) - numeric(TY, Y), numeric(Type, Result)) :- Result is X - Y, combine_types(TX, TY, Type). % SPARQL Tests, defined in section 11.4 op(X = Y, Result) :- rdf_equal(X, Y, Result). op(X \= Y, boolean(Result)) :- rdf_equal(X, Y, boolean(R0)), not(R0, Result). op(langmatches(simple_literal(Lang), simple_literal(Pat)), boolean(Result)) :- (langmatches(Lang, Pat) -> Result = true ; Result = false). op(regex(simple_literal(Pat), simple_literal(String)), boolean(Result)) :- (regex(Pat, String, '') -> Result = true ; Result = false). op(regex(simple_literal(Pat), simple_literal(String), simple_literal(Flags)), boolean(Result)) :- (regex(Pat, String, Flags) -> Result = true ; Result = false). % Numeric types follows the Xpath definitions of % http://www.w3.org/TR/xpath-functions/#numeric-functions % TBD: %% combine_types_div(+TypeLeft, +TypeRight, -Type) combine_types_div(TX, TY, T) :- rdf_equal(xsd:integer, IntType), xsdp_numeric_uri(TX, IntType), xsdp_numeric_uri(TY, IntType), !, rdf_equal(xsd:decimal, T). combine_types_div(TX, TY, T) :- combine_types(TX, TY, T). %% combine_types(+TypeLeft, +TypeRight, -Type) %combine_types(T, T, T) :- !. combine_types(TL, TR, T) :- xsdp_numeric_uri(TL, STL), xsdp_numeric_uri(TR, STR), promote_types(STL, STR, T). promote_types(TL, TR, T) :- type_index(TL, IL), type_index(TR, IR), TI is max(IL, IR), type_index(T, TI), !. term_expansion(type_index(NS:Local, I), type_index(URI, I)) :- rdf_global_id(NS:Local, URI). type_index(xsd:integer, 1). type_index(xsd:decimal, 2). type_index(xsd:float, 3). type_index(xsd:double, 4). %% rdf_equal(+RDFTerm, +RDFTerm, -Boolean) % % RDF Term equivalence. Described as lexical equivalence, except % where we have the logic to do value equivalence. rdf_equal(X, X, boolean(true)) :- !. rdf_equal(boolean(A), boolean(B), boolean(Eq)) :- !, eq_bool(A, B, Eq). rdf_equal(numeric(_, A), numeric(_, B), boolean(Eq)) :- !, (A =:= B -> Eq = true ; Eq = false). rdf_equal(_, _, boolean(false)). eq_bool(X, X, true) :- !. eq_bool(true, false, false) :- !. eq_bool(false, true, false) :- !. eq_bool(X, Y, true) :- boolean_value(X, V1), boolean_value(Y, V2), V1 == V2, !. eq_bool(_, _, false). %% boolean_value(+Content, -Bool) % % Convert the value from literal(xsd:boolean, Content) into % either 'true' or 'false'. boolean_value(true, true) :- !. boolean_value(false, false) :- !. boolean_value('0', false) :- !. boolean_value('', false) :- !. boolean_value(False, false) :- downcase_atom(False, false), !. boolean_value(_, true). :- dynamic sparql_op/2. % +Term, -Types make_op_declarations :- retractall(sparql_op(_,_)), findall(Head, clause(op(Head, _), _), Heads0), sort(Heads0, Heads), make_op_declarations(Heads). make_op_declarations([]). make_op_declarations([H0|T0]) :- functor(H0, Op, Arity), functor(G, Op, Arity), same_functor(G, T0, T1, T2), make_op_declaration([H0|T1]), make_op_declarations(T2). same_functor(F, [H|T0], [H|T], L) :- \+ \+ F = H, !, same_functor(F, T0, T, L). same_functor(_, L, [], L). make_op_declaration([Op|T]) :- functor(Op, Name, Arity), functor(G, Name, Arity), Op =.. [Name|Args], make_types(Args, 1, T, Types), assert(sparql_op(G, Types)). make_types([], _, _, []). make_types([H0|T0], I, Alt, [H|T]) :- alt_types(Alt, I, AT), list_to_set([H0|AT], Types), make_type(Types, H), I2 is I + 1, make_types(T0, I2, Alt, T). alt_types([], _, []). alt_types([H0|T0], I, [H|T]) :- arg(I, H0, H), alt_types(T0, I, T). make_type([T], no_eval) :- var(T), !. make_type([boolean(_)], boolean) :- !. make_type([numeric(_, _)], numeric) :- !. make_type([simple_literal(_)], simple_literal) :- !. make_type(_, any). :- make_op_declarations. /******************************* * CASTS * *******************************/ %% xsd_cast(+Term, -Type, -Arg) % % Deals with xsd:dateTime(?a), casting ?a to the XML Schema type % dateTime. Supported types are the numeric types, xsd:boolean and % xsd:dateTime. term_expansion(xsd_casts, Clauses) :- findall(Clause, xsd_cast_clause(Clause), Clauses). xsd_cast_clause(xsd_cast(Term, Type, Arg)) :- ( xsdp_numeric_uri(Type, _) ; rdf_equal(xsd:dateTime, Type) ; rdf_equal(xsd:boolean, Type) ), Term =.. [Type,Arg]. xsd_casts. %% eval_cast(+Type, +Value, -Result) % % Case Value to Type, resulting in a typed literal. Can we only % case simple literals? eval_cast(Type, literal(Value), Result) :- atom(Value), !, eval_typed_literal(Type, Value, Result). %% eval_function(+Term, -Result) % % Eval user-defined function. User-defined functions are of the % form sparql:function(Term, Result). eval_function(Term0, Result) :- Term0 =.. [F|Args0], eval_args(Args0, Args), Term =.. [F|Args], sparql:function(Term, Result0), !, eval(Result0, Result). eval_function(Term, boolean(error)) :- functor(Term, Name, Arity), functor(Gen, Name, Arity), clause(sparql:function(Gen, _Result), _Body), !. eval_function(Term, _) :- functor(Term, Name, Arity), throw(error(existence_error(sparql_function, Name/Arity), _)). eval_args([], []). eval_args([H0|T0], [H|T]) :- sparql_eval(H0, H), eval_args(T0, T). /******************************* * SUPPORT PREDICATES * *******************************/ %% not(+Bool, -Negated) not(true, false). not(false, true). %% bound(X) % % Does not evaluate args. If the argument is a function it % is always bound. bound(X) :- nonvar(X). %% str(+RDFTerm, -Atom) % % Extract lexical representation from RDFTerm. str(Var, _) :- var(Var), !, fail. str(literal(X), Str) :- !, str_literal(X, Str). str(IRI, IRI) :- atom(IRI), !, \+ rdf_is_bnode(IRI). str(Expr, Str) :- eval(Expr, Value), str_value(Value, Str). str_value(simple_literal(X), X) :- !. str_value(boolean(X), X) :- !. str_value(string(X), X) :- !. str_value(iri(IRI), IRI) :- !. str_literal(type(_, Str), Str) :- !. str_literal(lang(_, Str), Str) :- !. str_literal(Str, Str). %% lang(+RDFTerm, -Lang) % % Extract language specification from an RDFTerm lang(0, _) :- !, fail. % catch variables. lang(lang(Lang, _), Lang) :- !. lang(literal(lang(Lang, _)), Lang) :- !. lang(literal(_), ''). % Fail on typed? %% datatype(+RDFTerm, -IRI) % % Extract type specification from an RDFTerm datatype(0, _) :- !, fail. datatype(literal(type(Type, _)), iri(Type)) :- !. datatype(numeric(Type, _), iri(Type)) :- !. datatype(boolean(_), iri(Type)) :- !, rdf_equal(xsd:boolean, Type). datatype(Expr, Type) :- eval(Expr, Value), Value \== Expr, datatype(Value, Type). %% sparql_and(+A, +B, -Result) sparql_and(true, true, true) :- !. sparql_and(true, error, error) :- !. sparql_and(error, true, error) :- !. sparql_and(_, _, false). %% sparql_or(+A, +B, -Result) sparql_or(true, _, true) :- !. sparql_or(_, true, true) :- !. sparql_or(false, false, false) :- !. sparql_or(_, _, error). %% langmatches(+Lang, +Pattern) % % Section 11.4.11 function LangMatches. This is slow. Guess we % better move this to the RDF library. Note that none of the % functions return a language qualified literal and we therefore % we only have to consider the case where the argument is a % variable also appearing in the object-field of a rdf/3 call. langmatches('', _) :- !, fail. langmatches(_, *). langmatches(Lang, Pattern) :- atom_codes(Lang, LC), atom_codes(Pattern, PC), langmatches_codes(PC, LC). langmatches_codes([], []) :- !. langmatches_codes([], [0'-|_]) :- !. langmatches_codes([H|TP], [H|TC]) :- !, langmatches_codes(TP, TC). langmatches_codes([HP|TP], [HC|TC]) :- !, code_type(L, to_lower(HP)), code_type(L, to_lower(HC)), langmatches_codes(TP, TC). %% isiri(+IRI) % % True if IRI is an IRI. We get the argument un-evaluated. isiri(IRI) :- atom(IRI), !, \+ rdf_is_bnode(IRI). isiri(literal(_)) :- !, fail. isiri(Expr) :- eval(Expr, Value), Value = iri(IRI), \+ rdf_is_bnode(IRI). isblank(IRI) :- atom(IRI), !, rdf_is_bnode(IRI). isblank(literal(_)) :- !, fail. isblank(Expr) :- eval(Expr, Value), Value = iri(IRI), rdf_is_bnode(IRI). isliteral(literal(_)) :- !. isliteral(Atom) :- atom(Atom), !, fail. isliteral(Expr) :- eval(Expr, Value), Value \= iri(_). %% regex(+String, +Pattern, +Flags) % % TBD: % - Avoid XPCE % - Complete flags :- dynamic pattern_cache/3. % Pattern, Flags, Regex regex(String, Pattern, Flags) :- pattern_cache(Pattern, Flags, Regex), !, send(Regex, search, string(String)). regex(String, Pattern, Flags) :- make_regex(Pattern, Flags, Regex), send(Regex, lock_object, @on), asserta(pattern_cache(Pattern, Flags, Regex)), send(Regex, search, string(String)). make_regex(Pattern, i, Regex) :- !, new(Regex, regex(Pattern, @off)). make_regex(Pattern, _, Regex) :- !, new(Regex, regex(Pattern)). %% effective_boolean_value(+Expr, -Bool) % % See SPARQL document, section 11.2.2: Effecitive Boolean Value effective_boolean_value(boolean(X), boolean(True)) :- !, True = X. effective_boolean_value(string(X), boolean(True)) :- !, (X == '' -> True = false ; True = true). effective_boolean_value(simple_literal(X), boolean(True)) :- !, (X == '' -> True = false ; True = true). effective_boolean_value(numeric(_, X), boolean(True)) :- !, (X =:= 0 -> True = false ; True = true). effective_boolean_value(_, boolean(error)). %% sparql_eval(+Expr, -Results) % % Evaluate an expression. sparql_eval(Expr, Expr) :- is_rdf(Expr), !. sparql_eval(Expr, Result) :- eval(Expr, Result0), to_rdf(Result0, Result). to_rdf(numeric(Type, Value), literal(type(Type, Atom))) :- atom_number(Atom, Value). to_rdf(boolean(Val), literal(Type, Val)) :- rdf_equal(xsd:boolean, Type). to_rdf(type(T, Val), literal(type(T, Val))). to_rdf(simple_literal(L), literal(L)). to_rdf(iri(IRI), IRI). %% is_rdf(+Term) % % True if Term is a valid RDF term. is_rdf(0) :- !, fail. % catch variables is_rdf(IRI) :- atom(IRI). is_rdf(literal(_)).