/usr/share/Yap/semweb/rdf_compare.pl is in yap 6.2.2-6.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 | /* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@uva.nl
WWW: http://www.swi-prolog.org
Copyright (C): 2009, 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 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(rdf_compare,
[ rdf_equal_graphs/3 % +Graph1, +Graph2, -Substitutions
]).
:- use_module(library(semweb/rdf_db)).
:- use_module(library(apply)).
:- use_module(library(debug)).
/** <module> Compare RDF graphs
This library provides predicates that compare RDF graphs. The current
version only provides one predicate: rdf_equal_graphs/3 verifies that
two graphs are identical after proper labeling of the blank nodes.
Future versions of this library may contain more advanced operations,
such as diffing two graphs.
*/
%% rdf_equal_graphs(+GraphA, +GraphB, -Substition) is semidet.
%
% True if GraphA and GraphB are the same under Substition.
% Substition is a list of BNodeA = BNodeB, where BNodeA is a blank
% node that appears in GraphA and BNodeB is a blank node that
% appears in GraphB.
%
% @param GraphA is a list of rdf(S,P,O) terms
% @param GraphB is a list of rdf(S,P,O) terms
% @param Substition is a list if NodeA = NodeB terms.
% @tbd The current implementation is rather naive. After
% dealing with the subgraphs that contain no bnodes,
% it performs a fully non-deterministic substitution.
rdf_equal_graphs(A, B, Substitutions) :-
sort(A, SA),
sort(B, SB),
partition(contains_bnodes, SA, VA, GA),
partition(contains_bnodes, SB, VB, GB),
GA == GB,
compare_list(VA, VB, [], Substitutions), !.
contains_bnodes(rdf(S,P,O)) :-
( node_id(S)
; node_id(P)
; node_id(O)
), !.
compare_list([], [], S, S).
compare_list([H1|T1], In2, S0, S) :-
select(H2, In2, T2),
compare_triple(H1, H2, S0, S1),
compare_list(T1, T2, S1, S).
compare_triple(rdf(Subj1,P1,O1), rdf(Subj2, P2, O2), S0, S) :-
compare_field(Subj1, Subj2, S0, S1),
compare_field(P1, P2, S1, S2),
compare_field(O1, O2, S2, S).
compare_field(X, X, S, S) :- !.
compare_field(literal(X), xml(X), S, S) :- !. % TBD
compare_field(X, Id, S, S) :-
memberchk(X=Id, S), !.
compare_field(X, Y, S, [X=Y|S]) :-
\+ memberchk(X=_, S),
node_id(X),
node_id(Y),
debug(rdf_compare, 'Assume ~w = ~w~n', [X, Y]).
node_id(node(_)) :- !.
node_id(X) :-
rdf_is_bnode(X).
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