skos/commit

try to factor out some duplicated skos-specific code and move it to this cpack

diff --git a/lib/skos/json.pl b/lib/skos/json.pl
new file mode 100644
index 0000000..4f53a59
--- /dev/null
+++ b/lib/skos/json.pl
@@ -0,0 +1,23 @@
+:- module(skos_json, [
+	      json_all_literal_propvalues/3]).
+
+:- use_module(library('semweb/rdf_db')).
+:- use_module(library('semweb/rdf_label')).
+
+:- rdf_meta
+	json_all_literal_propvalues(r, r, -).
+
+%%	json_all_literal_propvalues(URI, Property, Dict) is det.
+%
+%	Dict is a dictionairy with language codes as keys an literal
+%	values for data property Property as values
+json_all_literal_propvalues(R,P,Definitions) :-
+	findall(Lang-Definition,
+		(   rdf_has(R, P, DefLit),
+		    literal_text(DefLit,Definition),
+		    (	DefLit = literal(lang(Lang, _))
+		    ->	true
+		    ;	Lang=lang_undefined
+		    )
+		), Pairs),
+	dict_pairs(Definitions, lang, Pairs).
diff --git a/lib/skos/util.pl b/lib/skos/util.pl
new file mode 100644
index 0000000..6c90d43
--- /dev/null
+++ b/lib/skos/util.pl
@@ -0,0 +1,49 @@
+:- module(skos_util, [
+	      skos_notation_ish/2,
+	      skos_all_labels/2,
+	      skos_related_concepts/2
+	  ]).
+
+:- use_module(library('semweb/rdf_db')).
+:- use_module(library('semweb/rdf_label')).
+
+%%	notation_ish(Concept, NotationIsh) is det.
+%
+%	Unify NotationIsh with a label extend by (notation).
+%	For notation, use the skos:notation or dc/dcterms:identifier
+skos_notation_ish(Concept, NotationIsh) :-
+	rdf_display_label(Concept, Label),
+	(   (rdf(Concept, skos:notation, N)
+	    ;	rdf_has(Concept, skos:notation, N)
+	    ;	rdf_has(Concept, dc:identifier, N)
+	    )
+	->  literal_text(N, LT),
+	    format(atom(NotationIsh), '~w (~w)', [Label, LT])
+	;   NotationIsh = Label
+	).
+
+
+%%	skos_all_labels(URI, Labels) is det.
+%
+%	Find all labels using rdf_label/2.
+%	Note that rdf_label itself is skos hooked...
+skos_all_labels(R,Labels) :-
+	findall(AltLabel, (rdf_label(R,Lit),
+			   literal_text(Lit, AltLabel)
+			  ),
+		Labels0),
+	sort(Labels0,Labels).
+
+
+%%	skos_related_concepts(?Resource, ?Concepts) is det.
+%
+%	Related Concepts are linked by skos:related to Resource.
+
+skos_related_concepts(S, Rs) :-
+	findall(R, skos_related(S, R), Rs0),
+	sort(Rs0, Rs).
+
+skos_related(R1, R2) :-
+	rdf_has(R1, skos:related, R2).
+skos_related(R2, R1) :-
+	rdf_has(R2, skos:related, R1).