1/*  Part of SWI-Prolog
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@cs.vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (C): 2016, VU University Amsterdam
    7
    8    This program is free software; you can redistribute it and/or
    9    modify it under the terms of the GNU General Public License
   10    as published by the Free Software Foundation; either version 2
   11    of the License, or (at your option) any later version.
   12
   13    This program is distributed in the hope that it will be useful,
   14    but WITHOUT ANY WARRANTY; without even the implied warranty of
   15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   16    GNU General Public License for more details.
   17
   18    You should have received a copy of the GNU General Public
   19    License along with this library; if not, write to the Free Software
   20    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   21
   22    As a special exception, if you link this library with other files,
   23    compiled with a Free Software compiler, to produce an executable, this
   24    library does not by itself cause the resulting executable to be covered
   25    by the GNU General Public License. This exception does not however
   26    invalidate any other reasons why the executable file might be covered by
   27    the GNU General Public License.
   28*/
   29
   30:- module(swish_render_rdf,
   31	  [ term_rendering//3			% +Term, +Vars, +Options
   32	  ]).   33:- use_module(library(semweb/rdf11)).   34:- use_module(library(http/html_write)).   35:- use_module(library(option)).   36:- use_module(library(uri)).   37:- use_module(library(lists)).   38:- use_module(library(apply)).   39:- use_module(library(error)).   40:- use_module(library(broadcast)).   41
   42:- use_module('../render').   43
   44:- register_renderer(rdf, "Render RDF terms").   45
   46/** <module> SWISH RDF renderer
   47
   48Render RDF data. This turns URIs into  links to the ClioPatria localview
   49and prints literal values using Turtle syntax.   Lists  of RDF terms are
   50rendered as an inline block with one   element  per line. Long lists are
   51truncated to the `max_depth` option  of the `answer_write_options` flag.
   52This can be overruled using e.g.,
   53
   54    :- use_rendering(rdf, [max_length(100)]).
   55*/
   56
   57%%	term_rendering(+Term, +Vars, +Options)//
   58%
   59%	Renders Term as  a  uri  or   Turtle  syntax  literal.  List are
   60%	rendered as a list of these.
   61
   62term_rendering(List, _Vars, Options) -->
   63	{ is_list(List), List \== [],
   64	  maplist(is_rdf, List),
   65	  truncate(List, Truncated, Options)
   66	},
   67	html(span([class('rdf-list'), style('display:inline-block')],
   68		  \rdf_list(Truncated, Options))).
   69term_rendering(Term, _Vars, Options) -->
   70	{ is_rdf(Term) }, !,
   71	rdf_link(Term, [target('rdf-link')|Options]).
   72
   73rdf_list([], _) --> [].
   74rdf_list([H|T], Options) -->
   75	html(div(class('rdf-list-element'),
   76		 \rdf_list_elem(H, Options))),
   77	rdf_list(T, Options).
   78
   79
   80rdf_list_elem(skipped(Skipped), _) --> !,
   81	html(span(class('rdf-list-skipped'),
   82		  '... skipped ~D ...'-[Skipped])).
   83rdf_list_elem(Elem, Options) -->
   84	rdf_link(Elem, [target('rdf-link')|Options]).
   85
   86truncate(List, Truncated, Options) :-
   87	(   option(max_length(Max), Options)
   88	->  true
   89	;   current_prolog_flag(answer_write_options, WrOptions),
   90	    option(max_depth(Max), WrOptions)
   91	),
   92	length(List, Len),
   93	Len + 1 > Max,
   94	Start is Max - 1,
   95	Skipped is Len-Max,
   96	length(Prefix, Start),
   97	append(Prefix, _, List),
   98	last(List, Last),
   99	append(Prefix, [skipped(Skipped), Last], Truncated).
  100truncate(List, List, _).
  101
  102%%	is_rdf(@Term)
  103%
  104%	True if Term is an RDF term.
  105
  106is_rdf(Term) :-
  107	is_uri(Term), !.
  108is_rdf(literal(Value)) :-
  109	is_literal(Value).
  110is_rdf(^^(Value,Type)) :- atom(Type), ground(Value).
  111is_rdf(@(Text,Lang)) :- atom(Lang), is_text(Text).
  112
  113is_uri(Term) :-
  114	atom(Term),
  115	(   uri_is_global(Term)
  116	->  true
  117	;   rdf_is_bnode(Term)
  118	).
  119
  120is_literal(Atomic) :- is_plain_literal(Atomic).
  121is_literal(type(Type, Literal)) :- is_uri(Type), is_plain_literal(Literal).
  122is_literal(lang(Lang, Literal)) :- atom(Lang),   is_text(Literal).
  123
  124is_plain_literal(Value) :-
  125	atomic(Value).
  126
  127is_text(Value) :- atom(Value), !.
  128is_text(Value) :- string(Value).
  129
  130%!	rdf_link(+Term, +Options)//
  131
  132rdf_link(Text@Lang, _Options) --> !,
  133	html(span(class('rdf-lang-literal'),
  134		  [ '"', span(class('rdf-lexical'), Text), '"@',
  135		    span(class('rdf-lang'), Lang)
  136		  ])).
  137rdf_link(Value^^Type, Options) --> !,
  138	{ rdf_lexical_form(Value^^Type, String^^Type)
  139	},
  140	html(span(class('rdf-typed-literal'),
  141		  [ '"', span(class('rdf-lexical'), String), '"^^',
  142		    \rdf_link(Type, Options)
  143		  ])).
  144rdf_link(literal(Literal), Options) --> !,
  145	rdf_literal_link(Literal, Options).
  146rdf_link(IRI, Options) -->
  147	{ rdf_global_id(Prefix:Local, IRI),
  148	  !,
  149	  a_options(IRI, Extra, Options)
  150	},
  151	html(a([href(IRI)|Extra],
  152	       [ span(class('rdf-pname'), Prefix), :,
  153		 span(class('rdf-local'), Local)
  154	       ])).
  155rdf_link(IRI, Options) -->
  156	{ must_be(atom, IRI),
  157	  a_options(IRI, Extra, Options)
  158	},
  159	html(a([href(IRI)|Extra],
  160	       [ span(class('rdf-iri'), IRI)
  161	       ])).
  162
  163
  164rdf_literal_link(type(Type,Value), Options) --> !,
  165	rdf_link(Value^^Type, Options).
  166rdf_literal_link(lang(Lang,Value), Options) --> !,
  167	rdf_link(Value@Lang, Options).
  168rdf_literal_link(Plain, Options) -->
  169	{ atom(Plain), !,
  170	  rdf_equal(String, xsd:string)
  171	},
  172	rdf_link(Plain^^String, Options).
  173
  174a_options(IRI, Extra, Options) :-
  175	(   broadcast_request(rdf_label(IRI, Label))
  176	->  Extra = [title(Label)|E1]
  177	;   E1 = Extra
  178	),
  179	(   option(target(Target), Options)
  180	->  E1 = [target(Target)]
  181	;   E1 = []
  182	)