swish/commit

ADDED: Extended RDF renderer to render lists of RDF terms.

diff --git a/lib/swish/render/rdf.pl b/lib/swish/render/rdf.pl
index 5e3dc66..74e9fc5 100644
--- a/lib/swish/render/rdf.pl
+++ b/lib/swish/render/rdf.pl
@@ -3,7 +3,7 @@
     Author:        Jan Wielemaker
     E-mail:        J.Wielemaker@cs.vu.nl
     WWW:           http://www.swi-prolog.org
-    Copyright (C): 2014, VU University Amsterdam
+    Copyright (C): 2016, VU University Amsterdam
 
     This program is free software; you can redistribute it and/or
     modify it under the terms of the GNU General Public License
@@ -31,33 +31,81 @@
 	  [ term_rendering//3			% +Term, +Vars, +Options
 	  ]).
 :- use_module(library(semweb/rdf_db)).
+:- use_module(library(http/html_write)).
 :- use_module(components(label)).
 :- use_module(library(uri)).
+:- use_module(library(lists)).
+:- use_module(library(apply)).
 :- use_module(library(swish/render)).
 
 :- register_renderer(rdf, "Render RDF terms").
 
 /** <module> SWISH RDF renderer
 
-Render RDF data.
+Render RDF data. This turns URIs into  links to the ClioPatria localview
+and prints literal values using Turtle syntax.   Lists  of RDF terms are
+rendered as an inline block with one   element  per line. Long lists are
+truncated to the `max_depth` option  of the `answer_write_options` flag.
+This can be overruled using e.g.,
+
+    :- use_rendering(rdf, [max_length(100)]).
 */
 
 %%	term_rendering(+Term, +Vars, +Options)//
 %
-%	Renders Term as a uri.  Furt
+%	Renders Term as  a  uri  or   Turtle  syntax  literal.  List are
+%	rendered as a list of these.
 
+term_rendering(List, _Vars, Options) -->
+	{ is_list(List), List \== [],
+	  maplist(is_rdf, List),
+	  truncate(List, Truncated, Options)
+	},
+	html(span([class('rdf-list'), style('display:inline-block')],
+		  \rdf_list(Truncated, Options))).
 term_rendering(Term, _Vars, Options) -->
-	{ ground(Term),
-	  is_rdf(Term)
-	}, !,
+	{ is_rdf(Term) }, !,
 	rdf_link(Term, [target('cliopatria-localview')|Options]).
 
+rdf_list([], _) --> [].
+rdf_list([H|T], Options) -->
+	html(div(class('rdf-list-element'),
+		 \rdf_list_elem(H, Options))),
+	rdf_list(T, Options).
+
+
+rdf_list_elem(skipped(Skipped), _) --> !,
+	html(span(class('rdf-list-skipped'),
+		  '... skipped ~D ...'-[Skipped])).
+rdf_list_elem(Elem, Options) -->
+	rdf_link(Elem, [target('cliopatria-localview')|Options]).
+
+truncate(List, Truncated, Options) :-
+	(   option(max_length(Max), Options)
+	->  true
+	;   current_prolog_flag(answer_write_options, WrOptions),
+	    option(max_depth(Max), WrOptions)
+	),
+	length(List, Len),
+	Len + 1 > Max,
+	Start is Max - 1,
+	Skipped is Len-Max,
+	length(Prefix, Start),
+	append(Prefix, _, List),
+	last(List, Last),
+	append(Prefix, [skipped(Skipped), Last], Truncated).
+truncate(List, List, _).
+
+%%	is_rdf(@Term)
+%
+%	True if Term is an RDF term.
+
 is_rdf(Term) :-
 	is_uri(Term), !.
 is_rdf(literal(Value)) :-
 	is_literal(Value).
-is_rdf(^^(_,Type)) :- atom(Type).
-is_rdf(@(_,Lang)) :- atom(Lang).
+is_rdf(^^(Value,Type)) :- atom(Type), ground(Value).
+is_rdf(@(Text,Lang)) :- atom(Lang), is_text(Text).
 
 is_uri(Term) :-
 	atom(Term),
@@ -68,7 +116,10 @@ is_uri(Term) :-
 
 is_literal(Atomic) :- is_plain_literal(Atomic).
 is_literal(type(Type, Literal)) :- is_uri(Type), is_plain_literal(Literal).
-is_literal(lang(Lang, Literal)) :- atom(Lang),   is_plain_literal(Literal).
+is_literal(lang(Lang, Literal)) :- atom(Lang),   is_text(Literal).
 
 is_plain_literal(Value) :-
 	atomic(Value).
+
+is_text(Value) :- atom(Value), !.
+is_text(Value) :- string(Value).