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    1/*  Part of ClioPatria SeRQL and SPARQL server
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (c)  2010-2018, VU University Amsterdam
    7                              CWI, Amsterdam
    8    All rights reserved.
    9
   10    Redistribution and use in source and binary forms, with or without
   11    modification, are permitted provided that the following conditions
   12    are met:
   13
   14    1. Redistributions of source code must retain the above copyright
   15       notice, this list of conditions and the following disclaimer.
   16
   17    2. Redistributions in binary form must reproduce the above copyright
   18       notice, this list of conditions and the following disclaimer in
   19       the documentation and/or other materials provided with the
   20       distribution.
   21
   22    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   23    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   24    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   25    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   26    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   27    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   28    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   29    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   30    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   32    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   33    POSSIBILITY OF SUCH DAMAGE.
   34*/
   35
   36:- module(cpa_browse,
   37          [ graph_info//1,              % +Graph
   38            graph_as_resource//2,       % +Graph, +Options
   39            graph_actions//1,           % +Graph
   40            list_resource//2,           % +URI, +Options
   41            context_graph//2            % +URI, +Options
   42          ]).   43:- use_module(library(http/http_dispatch)).   44:- use_module(library(http/http_parameters)).   45:- use_module(library(http/html_write)).   46:- use_module(library(http/js_write)).   47:- use_module(library(http/html_head)).   48:- use_module(library(http/http_wrapper)).   49:- use_module(library(http/yui_resources)).   50:- use_module(library(http/http_path)).   51:- use_module(library(http/cp_jquery)).   52
   53:- use_module(library(semweb/rdf_db)).   54:- use_module(library(semweb/rdfs)).   55:- use_module(library(semweb/rdf_litindex)).   56:- use_module(library(semweb/rdf_persistency)).   57
   58:- use_module(library(aggregate)).   59:- use_module(library(lists)).   60:- use_module(library(pairs)).   61:- use_module(library(debug)).   62:- use_module(library(option)).   63:- use_module(library(apply)).   64:- use_module(library(settings)).   65
   66:- use_module(components(label)).   67:- use_module(components(simple_search)).   68:- use_module(components(graphviz)).   69:- use_module(components(basics)).   70:- use_module(api(lod_crawler)).   71:- use_module(api(sesame)).   72:- use_module(library(semweb/rdf_abstract)).   73:- use_module(library(semweb/rdf_label)).   74
   75:- use_module(user(user_db)).   76
   77
   78/** <module> ClioPatria RDF data browser
   79
   80This module implements basic browsing of an  RDF repository. This is not
   81intended to be used as an end-user application, but for the developer to
   82gain insight in the data in the   RDF  store. That said, the distinction
   83between end-user and developer  can  be   rather  vague  if  we consider
   84`back-office'   applications.   To   a   certain   extend,   back-office
   85applications  are  considered  within  the  scope  of  this  module  and
   86therefore it provides several  hooks   and  defines several `components'
   87that allow back-office applications to reuse this infrastructure.
   88
   89@see    cliopatria(hooks) for available hooks.
   90*/
   91
   92                 /*******************************
   93                 *            PATHS             *
   94                 *******************************/
   95
   96:- http_handler(rdf_browser(.),
   97                http_404([index(list_graphs)]),
   98                [spawn(cliopatria), prefix]).   99:- http_handler(rdf_browser(list_graphs),     list_graphs,     []).  100:- http_handler(rdf_browser(list_graph),      list_graph,      []).  101:- http_handler(rdf_browser(list_classes),    list_classes,    []).  102:- http_handler(rdf_browser(list_instances),  list_instances,  []).  103:- http_handler(rdf_browser(list_predicates), list_predicates, []).  104:- http_handler(rdf_browser(list_predicate_resources),
  105                                              list_predicate_resources, []).  106:- http_handler(rdf_browser(list_resource),   list_resource,   []).  107:- http_handler(rdf_browser(list_triples),    list_triples,    []).  108:- http_handler(rdf_browser(list_triples_with_object),
  109                                              list_triples_with_object, []).  110:- http_handler(rdf_browser(list_triples_with_literal),
  111                                              list_triples_with_literal, []).  112
  113:- http_handler(rdf_browser(list_prefixes),   list_prefixes,   []).  114:- http_handler(rdf_browser(search),          search,          []).  115:- http_handler(rdf_browser(multigraph_action), multigraph_action,
  116                [ time_limit(infinite) ]).  117
  118
  119:- meta_predicate
  120    table_rows(3, +, ?, ?),
  121    table_rows_top_bottom(3, +, +, +, ?, ?),
  122    html_property_table(?, 0, ?, ?).  123
  124%!  list_graphs(+Request)
  125%
  126%   Display a page holding a table with all RDF graphs.  The graphs
  127%   are sorted to the number of triples.
  128
  129list_graphs(_Request) :-
  130    findall(Count-Graph,
  131            (   rdf_graph(Graph),
  132                graph_triples(Graph, Count)
  133            ),
  134            Pairs),
  135    keysort(Pairs, Sorted),
  136    pairs_values(Sorted, UpCount),
  137    reverse(UpCount, DownCount),
  138    append(DownCount, [virtual(total)], Rows),
  139    reply_html_page(cliopatria(default),
  140                    title('RDF Graphs'),
  141                    [ h1('Named graphs in the RDF store'),
  142                      \warn_volatile,
  143                      \graph_table(Rows, [])
  144                    ]).
  145
  146:- if(current_predicate(rdf_persistency_property/1)).  147warn_volatile -->
  148    { rdf_persistency_property(access(read_only)),
  149      !,
  150      rdf_persistency_property(directory(Dir))
  151    },
  152    html(div(class(msg_warning),
  153             [ 'WARNING: The persistent store ', code(Dir), ' was loaded in ',
  154               b('read-only'), ' mode.  All changes will be lost when ',
  155               'the server is stopped.'
  156             ])).
  157:- endif.  158warn_volatile --> [].
  159
  160:- if((rdf_version(V),V>=30000)).  161graph_triples(Graph, Count) :-
  162    rdf_statistics(triples_by_graph(Graph, Count)).
  163:- else.  164graph_triples(Graph, Count) :-                  % RDF-DB < 3.0
  165    rdf_statistics(triples_by_file(Graph, Count)).
  166:- endif.  167
  168graph_table(Graphs, Options) -->
  169    { option(top_max(TopMax), Options, 500),
  170      option(top_max(BottomMax), Options, 500),
  171      http_link_to_id(multigraph_action, [], Action),
  172      graph_actions(Options, ActionOptions)
  173    },
  174    html_requires(css('rdf.css')),
  175    html(form([ action(Action),
  176                class('graph-table')
  177              ],
  178              [ table(class(block),
  179                      [ \graph_table_header
  180                      | \table_rows_top_bottom(
  181                             graph_row(ActionOptions), Graphs,
  182                             TopMax, BottomMax)
  183                      ]),
  184                \multigraph_actions(ActionOptions)
  185              ])),
  186    mgraph_action_script.
  187
  188graph_table_header -->
  189    html(tr([ th('RDF Graph'),
  190              th('Triples'),
  191              th('Modified'),
  192              th('Persistency')
  193            ])).
  194
  195graph_row(_, virtual(total)) -->
  196    !,
  197    { rdf_statistics(triples(Count))
  198    },
  199    html([ th(class(total), 'Total #triples:'),
  200           \nc('~D', Count, [class(total)]),
  201           td([],[]),  % Empty cell for persistency column
  202           td([],[])   % Empty cell for modified column
  203         ]).
  204graph_row(Options, Graph) -->
  205    { graph_triples(Graph, Count)
  206
  207    },
  208    html([ td(\graph_link(Graph)),
  209           \nc('~D', Count),
  210           \modified(Graph),
  211           td(style('text-align:center'), \persistency(Graph)),
  212           \graph_checkbox(Graph, Options)
  213         ]).
  214
  215modified(Graph) -->
  216    { rdf_graph_property(Graph, source_last_modified(Time)),
  217      format_time(string(Modified), '%+', Time), !
  218    },
  219    html(td([class('file-time')], Modified)).
  220modified(Graph) -->
  221    { rdf_journal_file(Graph, File),
  222      time_file(File, Time),
  223      format_time(string(Modified), '%+', Time)
  224    },
  225    html(td([class('file-time')], Modified)).
  226modified(_Graph) -->
  227    html(td([class('file-time')], '')).
  228
  229graph_link(Graph) -->
  230    { http_link_to_id(list_graph, [graph=Graph], URI)
  231    },
  232    html(a(href(URI), Graph)).
  233
  234persistency(Graph) -->
  235    { rdf_graph_property(Graph, persistent(true)) },
  236    !,
  237    snapshot(Graph),
  238    journal(Graph).
  239persistency(_) -->
  240    { http_absolute_location(icons('volatile.png'), Img, [])
  241    },
  242    html(img([ class('in-text'),
  243               title('Graph is not persistent'),
  244               src(Img)
  245             ])).
  246
  247snapshot(Graph) -->
  248    { rdf_snapshot_file(Graph, _),
  249      http_absolute_location(icons('snapshot.png'), Img, [])
  250    },
  251    html(img([ class('in-text'),
  252               title('Graph has persistent snapshot'),
  253               src(Img)
  254             ])).
  255snapshot(_) --> [].
  256
  257journal(Graph) -->
  258    { rdf_journal_file(Graph, _),
  259      http_absolute_location(icons('journal.png'), Img, [])
  260    },
  261    html(img([ class('in-text'),
  262               title('Graph has a journal'),
  263               src(Img)
  264             ])).
  265journal(_) --> [].
  266
  267%!  graph_actions(+Options0, -Options).
  268%!  multigraph_actions(+Options)
  269%
  270%   Deal with actions on multiple graphs.
  271
  272graph_actions(Options, [show_actions(true)|Options]) :-
  273    logged_on(User),
  274    !,
  275    catch(check_permission(User, write(_, unload(user))), _, fail),
  276    !.
  277graph_actions(Options, Options).
  278
  279graph_checkbox(Graph, Options) -->
  280    { option(show_actions(true), Options) },
  281    !,
  282    html(td(class('no-border'),
  283            input([type(checkbox),name(graph),value(Graph),
  284                   class('graph-select')]))).
  285graph_checkbox(_, _) --> [].
  286
  287multigraph_actions(Options) -->
  288    { option(show_actions(true), Options),
  289      !,
  290      findall(Action-Format,
  291              clause(graph_action(Action,Format,_), _),
  292              Pairs)
  293    },
  294    html([ ul([ class('multi-graph-actions')
  295              ],
  296              \li_graph_actions(Pairs))
  297         ]).
  298multigraph_actions(_) --> [].
  299
  300li_graph_actions([]) --> [].
  301li_graph_actions([H|T]) --> li_graph_action(H), li_graph_actions(T).
  302
  303li_graph_action(Action-Format) -->
  304    { atomic_list_concat([Pre,Post], '~w', Format) },
  305    html(li([ Pre,
  306              input([ type(submit), name(action), value(Action) ]),
  307              Post
  308            ])).
  309
  310mgraph_action_script -->
  311    html_requires(jquery),
  312    js_script({|javascript||
  313function showActions(time) {
  314  if ( time === undefined ) time = 400;
  315  var val = [];
  316  $('.graph-table :checkbox:checked').each(function(i) {
  317    val[i] = $(this).val();
  318  });
  319  if ( val.length == 0 )
  320    $(".multi-graph-actions").hide(time);
  321  else
  322    $(".multi-graph-actions").show(time);
  323}
  324
  325$(function() {
  326  showActions(0);
  327  $(".graph-table .graph-select").on('click', showActions);
  328});
  329              |}).
  330
  331%!  multigraph_action(Request)
  332%
  333%   HTTP Handler for user actions on multiple graphs.
  334
  335multigraph_action(Request) :-
  336    findall(Action, clause(graph_action(Action,_,_), _), Actions),
  337    http_parameters(Request,
  338                    [ graph(Graphs, [list(atom)]),
  339                      action(Action, [oneof(Actions)])
  340                    ]),
  341    clause(graph_action(Action,Format,_), _),
  342    api_action(Request, multigraph_action(Action, Graphs), html,
  343               Format-[Action]).
  344
  345multigraph_action(Action, Graphs) :-
  346    forall(member(Graph, Graphs),
  347           ( print_message(informational,
  348                           format('Processing ~w ...', [Graph])),
  349             graph_action(Action, _, Graph))).
  350
  351graph_action('Delete', '~w selected graphs', Graph) :-
  352    rdf_unload_graph(Graph).
  353graph_action(volatile, 'Make selected graphs ~w', Graph) :-
  354    rdf_persistency(Graph, false).
  355graph_action(persistent, 'Make selected graphs ~w', Graph) :-
  356    rdf_persistency(Graph, true).
  357graph_action('Merge journals', '~w for selected graphs', Graph) :-
  358    rdf_flush_journals([graph(Graph)]).
  359
  360
  361%!  list_graph(+Request)
  362%
  363%   HTTP handler that provides information   about an individual RDF
  364%   graph. The output is an HTML table.
  365
  366list_graph(Request) :-
  367    http_parameters(Request,
  368                    [ graph(Graph,
  369                            [description('Name of the graph to describe')])
  370                    ]),
  371    (   rdf_graph(Graph)
  372    ->  true
  373    ;   http_404([], Request)
  374    ),
  375    reply_html_page(cliopatria(default),
  376                    title('RDF Graph ~w'-[Graph]),
  377                    [ h1('Summary information for graph "~w"'-[Graph]),
  378                      \simple_search_form([ id(ac_find_in_graph),
  379                                            filter(graph(Graph)),
  380                                            label('Search this graph')
  381                                          ]),
  382                      \graph_info(Graph),
  383                      \graph_as_resource(Graph, []),
  384                      \graph_persistency(Graph),
  385                      \graph_actions(Graph),
  386                      \uri_info(Graph, Graph)
  387                    ]).
  388
  389%!  graph_info(+Graph)//
  390%
  391%   HTML component that shows  -statistical-   properties  about the
  392%   given named graph.
  393
  394graph_info(Graph) -->
  395    html_property_table(row(P,V),
  396                        graph_property(Graph,P,V)).
  397
  398:- dynamic
  399    graph_property_cache/3.  400
  401graph_property(Graph, P, V) :-
  402    graph_property_cache(Graph, MD5, Pairs),
  403    rdf_md5(Graph, MD5),
  404    !,
  405    member(P0-V, Pairs),
  406    P =.. [P0,Graph].
  407graph_property(Graph, P, V) :-
  408    retractall(graph_property_cache(Graph, _, _)),
  409    findall(P-V, graph_property_nc(Graph, P, V), Pairs),
  410    rdf_md5(Graph, MD5),
  411    assert(graph_property_cache(Graph, MD5, Pairs)),
  412    member(P0-V, Pairs),
  413    P =.. [P0,Graph].
  414
  415graph_property_nc(Graph, source, Source) :-
  416    rdf_source(Graph, Source).
  417graph_property_nc(Graph, triples, int(Triples)) :-
  418    graph_triples(Graph, Triples).
  419graph_property_nc(Graph, predicate_count, int(Count)) :-
  420    aggregate_all(count, predicate_in_graph(Graph, _P), Count).
  421graph_property_nc(Graph, subject_count, int(Count)) :-
  422    aggregate_all(count, subject_in_graph(Graph, _P), Count).
  423graph_property_nc(Graph, bnode_count, int(Count)) :-
  424    aggregate_all(count, bnode_in_graph(Graph, _P), Count).
  425graph_property_nc(Graph, type_count, int(Count)) :-
  426    aggregate_all(count, type_in_graph(Graph, _P), Count).
  427
  428predicate_in_graph(Graph, P) :-
  429    rdf_current_predicate(P),
  430    once(rdf(_,P,_,Graph)).
  431
  432%!  subject_in_graph(+Graph, -Subject)
  433%
  434%   Generate the distinct subjects in a graph. There are two ways to
  435%   do this: first the subjects and then  whether they appear in the
  436%   graph or the other way around. At   least this has the advantage
  437%   that we get distinct subjects for free.
  438
  439subject_in_graph(Graph, S) :-
  440    graph_triples(Graph, Count),
  441    rdf_statistics(triples(Total)),
  442    Count * 10 > Total,            % Graph has more than 10% of triples
  443    !,
  444    rdf_subject(S),
  445    once(rdf(S, _, _, Graph)).
  446subject_in_graph(Graph, S) :-
  447    findall(S, rdf(S,_,_,Graph), List),
  448    sort(List, Subjects),
  449    member(S, Subjects).
  450
  451bnode_in_graph(Graph, S) :-
  452    graph_triples(Graph, Count),
  453    rdf_statistics(triples(Total)),
  454    Count * 10 > Total,
  455    !,
  456    rdf_subject(S),
  457    rdf_is_bnode(S),
  458    once(rdf(S, _, _, Graph)).
  459bnode_in_graph(Graph, S) :-
  460    findall(S, (rdf(S,_,_,Graph), rdf_is_bnode(S)), List),
  461    sort(List, Subjects),
  462    member(S, Subjects).
  463
  464
  465
  466%!  type_in_graph(+Graph, -Class)
  467%
  468%   Generate the unique types in Graph
  469
  470:- thread_local
  471    type_seen/1.  472
  473type_in_graph(Graph, Class) :-
  474    call_cleanup(type_in_graph2(Graph, Class),
  475                 retractall(type_seen(_))).
  476
  477type_in_graph2(Graph, Class) :-
  478    subject_in_graph(Graph, S),
  479    (   rdf_has(S, rdf:type, Class)
  480    *-> true
  481    ;   rdf_equal(Class, rdfs:'Resource')
  482    ),
  483    (   type_seen(Class)
  484    ->  fail
  485    ;   assert(type_seen(Class))
  486    ).
  487
  488
  489%!  graph_persistency(+Graph)//
  490%
  491%   Show information about the persistency of the graph
  492
  493graph_persistency(Graph) -->
  494    { rdf_graph_property(Graph, persistent(true)),
  495      (   rdf_journal_file(Graph, _)
  496      ;   rdf_snapshot_file(Graph, _)
  497      )
  498    },
  499    !,
  500    html([ h1('Persistency information'),
  501           table(class(block),
  502                 [ tr([ td(class('no-border'),[]),
  503                        th('File'), th('Size'),th('Modified'),
  504                        td(class('no-border'),[])
  505                      ]),
  506                   \graph_shapshot(Graph),
  507                   \graph_journal(Graph)
  508                 ])
  509         ]).
  510graph_persistency(Graph) -->
  511    { rdf_graph_property(Graph, persistent(true))
  512    },
  513    !,
  514    html([ h1('Persistency information'),
  515           p('The graph has no associated persistency files')
  516         ]).
  517graph_persistency(_Graph) -->
  518    [].
  519
  520graph_shapshot(Graph) -->
  521    { rdf_snapshot_file(Graph, File)
  522    },
  523    html(tr([ th(class('file-role'), 'Snapshot'),
  524              \file_info(File)
  525            ])).
  526graph_shapshot(_) --> [].
  527
  528
  529graph_journal(Graph) -->
  530    { rdf_journal_file(Graph, File)
  531    },
  532    html(tr([ th(class('file-role'), 'Journal'),
  533              \file_info(File),
  534              \flush_journal_button(Graph)
  535            ])).
  536graph_journal(_) --> [].
  537
  538flush_journal_button(Graph) -->
  539    { http_link_to_id(flush_journal, [], HREF)
  540    },
  541    html(td(class('no-border'),
  542            form(action(HREF),
  543                 [ input([type(hidden), name(graph), value(Graph)]),
  544                   input([type(hidden), name(resultFormat), value(html)]),
  545                   input([type(submit), value('Merge journal')])
  546                 ]))).
  547
  548
  549file_info(File) -->
  550    { size_file(File, Size),
  551      time_file(File, Time),
  552      format_time(string(Modified), '%+', Time)
  553    },
  554    html([ td(class('file-name'), File),
  555           td(class('int'), \n(human, Size)),
  556           td(class('file-time'), Modified)
  557         ]).
  558
  559
  560%!  graph_actions(+Graph)// is det.
  561%
  562%   Provide a form for basic actions on the graph
  563
  564graph_actions(Graph) -->
  565    html([ h2('Actions'),
  566           ul(class(graph_actions),
  567              [ \li_export_graph(Graph, show),
  568                \li_export_graph(Graph, download),
  569                \li_schema_graph(Graph),
  570                \li_delete_graph(Graph),
  571                \li_persistent_graph(Graph)
  572              ])
  573         ]).
  574
  575li_delete_graph(Graph) -->
  576    { logged_on(User),
  577      catch(check_permission(User, write(_, unload(Graph))), _, fail),
  578      !,
  579      http_link_to_id(unload_graph, [], Action)
  580    },
  581    html(li(form(action(Action),
  582                 [ input([type(hidden), name(graph), value(Graph)]),
  583                   input([type(hidden), name(resultFormat), value(html)]),
  584                   input([class(gaction), type(submit), value('Delete')]),
  585                   ' this graph'
  586                 ]))).
  587li_delete_graph(_) --> [].
  588
  589li_persistent_graph(Graph) -->
  590    { logged_on(User),
  591      catch(check_permission(User, write(_, persistent(Graph))), _, fail),
  592      !,
  593      http_link_to_id(modify_persistency, [], Action),
  594      (   rdf_graph_property(Graph, persistent(true))
  595      ->  Op = (volatile),   Value = off
  596      ;   Op = (persistent), Value = on
  597      )
  598    },
  599    !,
  600    html(li(form(action(Action),
  601                 [ input([type(hidden), name(graph), value(Graph)]),
  602                   input([type(hidden), name(resultFormat), value(html)]),
  603                   input([type(hidden), name(persistent), value(Value)]),
  604                   'Make this graph ',
  605                   input([class(gaction), type(submit), value(Op)])
  606                 ]))).
  607li_persistent_graph(_) --> [].
  608
  609li_schema_graph(Graph) -->
  610    { http_link_to_id(export_graph_schema, [], Action),
  611      download_options(show, Label, MimeType, Title)
  612    },
  613    html(li(form(action(Action),
  614                 [ input([type(hidden), name(graph), value(Graph)]),
  615                   input([type(hidden), name(mimetype), value(MimeType)]),
  616                   'Compute a schema for this graph and ',
  617                   input([class(saction), type(submit), value(Label),
  618                          title(Title)
  619                         ]),
  620                   ' the result as ',
  621                   \dl_format_menu
  622                 ]))).
  623
  624li_export_graph(Graph, How) -->
  625    { http_link_to_id(export_graph, [], Action),
  626      download_options(How, Label, MimeType, Title)
  627    },
  628    html(li(form(action(Action),
  629                 [ input([type(hidden), name(graph), value(Graph)]),
  630                   input([type(hidden), name(mimetype), value(MimeType)]),
  631                   input([class(gaction), type(submit), value(Label),
  632                          title(Title)
  633                         ]),
  634                   ' this graph as ',
  635                   \dl_format_menu
  636                 ]))).
  637
  638download_options(show,     'Show',     'text/plain',
  639                 'Returns graph with MIME-type text/plain, \n\c
  640                  so it will be displayed in your browser').
  641download_options(download, 'Download', default,
  642                 'Return graph with its RDF MIME-type, \n\c
  643                  so most browsers will save it').
  644
  645dl_format_menu -->
  646    html(select(name(format),
  647                [ option([value(turtle),selected],  'Turtle'),
  648                  option([value(canonical_turtle)], 'Canonical Turtle'),
  649                  option([value(rdfxml)],           'RDF/XML')
  650                ])).
  651
  652
  653%!  list_classes(+Request)
  654%
  655%   HTTP handler that lists all classes  of all subjects that appear
  656%   in the named graph. The  output  is   an  HTML  page holding all
  657%   referenced classes sorted by their label.
  658
  659list_classes(Request) :-
  660    http_parameters(Request,
  661                    [ graph(Graph, [description('Name of the graph')])
  662                    ]),
  663    types_in_graph(Graph, Map),
  664    sort_pairs_by_label(Map, Sorted),
  665    reply_html_page(cliopatria(default),
  666                    title('Classes in graph ~w'-[Graph]),
  667                    [ h1(['Classes in graph ', \graph_link(Graph)]),
  668                      \class_table(Sorted, Graph, [])
  669                    ]).
  670
  671class_table(Pairs, Graph, Options) -->
  672    { option(top_max(TopMax), Options, 500),
  673      option(top_max(BottomMax), Options, 500)
  674    },
  675    html_requires(css('rdf.css')),
  676    html(table(class(block),
  677               [ \class_table_header
  678               | \table_rows_top_bottom(class_row(Graph), Pairs,
  679                                        TopMax, BottomMax)
  680               ])).
  681
  682class_table_header -->
  683    html(tr([ th('Class'),
  684              th('#Instances')
  685            ])).
  686
  687class_row(Graph, Class) -->
  688    { atom(Class),
  689      !,
  690      findall(I, rdf_has(I, rdf:type, Class, Graph), IL),
  691      sort(IL, Classes),
  692      length(Classes, InstanceCount)
  693    },
  694    class_row(Graph, Class-InstanceCount).
  695class_row(Graph, Class-InstanceCount) -->
  696    { (   var(Graph)
  697      ->  Params = [class(Class)]
  698      ;   Params = [graph(Graph), class(Class)]
  699      ),
  700      http_link_to_id(list_instances, Params, ILink)
  701    },
  702    html([ td(\rdf_link(Class, [role(class)])),
  703           td(class(int), a(href(ILink), InstanceCount))
  704         ]).
  705
  706%!  types_in_graph(+Graph, -Map:list(Type-InstanceCount))
  707%
  708%   Generate a map of all types that appear in Graph with a count on
  709%   the number of instances.
  710
  711types_in_graph(Graph, Map) :-
  712    findall(S, subject_in_graph(Graph, S), Subjects),
  713    types(Subjects, Pairs),
  714    transpose_pairs(Pairs, TypeSubj),
  715    group_pairs_by_key(TypeSubj, TypeSubjs),
  716    maplist(instance_count, TypeSubjs, Map).
  717
  718types([], []).
  719types([S|T0], Types) :-
  720    call_det(type_of(S,C), Det),
  721    !,
  722    (   Det == true
  723    ->  Types = [S-C|T],
  724        types(T0, T)
  725    ;   findall(C2, type_of(S,C2), Cs),
  726        multi_class(Cs, S, Types, PT),
  727        types(T0, PT)
  728    ).
  729
  730multi_class([], _, Pairs, Pairs).
  731multi_class([H|T], S, [S-H|Pairs], PT) :-
  732    multi_class(T, S, Pairs, PT).
  733
  734
  735type_of(Subject, Type) :-
  736    (   rdf_has(Subject, rdf:type, Type)
  737    *-> true
  738    ;   rdf_equal(Type, rdfs:'Resource')
  739    ).
  740
  741:- meta_predicate
  742    call_det(0, -).  743
  744call_det(G, Det) :-
  745    call(G),
  746    deterministic(Det).
  747
  748instance_count(Type-Instances, Type-Count) :-
  749    length(Instances, Count).
  750
  751%!  instance_in_graph(?Graph, ?Class, +Type,
  752%!                    -Subject, -PropertyCount) is nondet.
  753%
  754%   True of Subject is  an  instance   of  Class  with PropertyCount
  755%   properties provided from Graph.
  756
  757instance_in_graph(Graph, Class, any, S, C) :-
  758    !,
  759    instance_in_graph(Graph, Class, S, C).
  760instance_in_graph(Graph, Class, bnode, S, C) :-
  761    !,
  762    freeze(S, rdf_is_bnode(S)),
  763    instance_in_graph(Graph, Class, S, C).
  764
  765
  766instance_in_graph(Graph, Class, S, C) :-
  767    var(Class),
  768    !,
  769    subject_in_graph(Graph, S),
  770    property_count(Graph, S, C).
  771instance_in_graph(Graph, Class, S, C) :-
  772    rdf_equal(Class, rdfs:'Resource'),
  773    !,
  774    (   rdf_has(S, rdf:type, Class),
  775        once(rdf(S, _, _, Graph))
  776    ;   subject_in_graph(Graph, S),
  777        \+ rdf_has(S, rdf:type, _)
  778    ),
  779    property_count(Graph, S, C).
  780instance_in_graph(Graph, Class, S, C) :-
  781    rdf_has(S, rdf:type, Class),
  782    once(rdf(S, _, _, Graph)),
  783    property_count(Graph, S, C).
  784
  785property_count(Graph, S, Count) :-
  786    aggregate_all(count, rdf(S, _, _, Graph), Count).
  787
  788%!  graph_as_resource(+Graph, Options)// is det.
  789%
  790%   Show resource info for a graph if it is described.
  791
  792graph_as_resource(Graph, Options) -->
  793    { (   rdf(Graph, _, _)
  794      ;   rdf(_, Graph, _)
  795      ;   rdf(_, _, Graph)
  796      ), !
  797    },
  798    html([ h2([ 'Local view for "',
  799                \location(Graph, _), '"'
  800              ]),
  801           \local_view(Graph, _, Options)
  802         ]).
  803graph_as_resource(_, _) --> [].
  804
  805
  806                 /*******************************
  807                 *        LIST INSTANCES        *
  808                 *******************************/
  809
  810%!  list_instances(+Request)
  811%
  812%   HTTP handler that lists instances that satisfy certain criteria.
  813
  814list_instances(Request) :-
  815    http_parameters(Request,
  816                    [ class(Class,
  817                            [ optional(true),
  818                              description('Limit to instances of this class')
  819                            ]),
  820                      graph(Graph,
  821                            [ optional(true),
  822                              description('Limit to have at least \c
  823                                               one property in graph')
  824                            ]),
  825                      type(Type,
  826                           [ oneof([any, bnode]),
  827                             default(any),
  828                             description('Any instance or only bnodes?')
  829                           ]),
  830                      resource_format(Format,
  831                            [ default(DefaultFormat),
  832                              atom,
  833                              description('Display format as passed to rdf_link//2 ')
  834                            ]),
  835                      sortBy(Sort,
  836                             [ oneof([label,properties]),
  837                               default(label),
  838                               description('How to sort the result-table')
  839                             ])
  840                    ]),
  841    setting(resource_format, DefaultFormat),
  842    findall(I-PC, instance_in_graph(Graph, Class, Type, I, PC), IPairs),
  843    sort_pairs_by_label(IPairs, TableByName),
  844    (   Sort == properties
  845    ->  reverse(TableByName, RevTableByName),
  846        transpose_pairs(RevTableByName, FPairsUp),
  847        reverse(FPairsUp, FPairsDown),
  848        flip_pairs(FPairsDown, Table)
  849    ;   Table = TableByName
  850    ),
  851
  852    reply_html_page(cliopatria(default),
  853                    title(\instance_table_title(Graph, Class, Sort)),
  854                    [ h1(\html_instance_table_title(Graph, Class, Sort)),
  855                      \instance_table(Table, [resource_format(Format)])
  856                    ]).
  857
  858instance_table_title(Graph, Class, Sort) -->
  859    { var(Class) },
  860    !,
  861    html('Instances in ~w sorted by ~w'-
  862         [Graph, Sort]).
  863instance_table_title(Graph, Class, Sort) -->
  864    { rdf_display_label(Class, Label) },
  865    html('Instances of ~w in ~w sorted by ~w'-
  866         [Label, Graph, Sort]).
  867
  868html_instance_table_title(Graph, Class, Sort) -->
  869    html([ 'Instances',
  870           \of_class(Class),
  871           \in_graph(Graph),
  872           \sorted_by(Sort)
  873         ]).
  874
  875of_class(Class) -->
  876    { var(Class) },
  877    !.
  878of_class(Class) -->
  879    html([' of class ', \rdf_link(Class, [role(class)])]).
  880
  881in_graph(Graph) -->
  882    { var(Graph) },
  883    !.
  884in_graph(Graph) -->
  885    html([' in graph ', \graph_link(Graph)]).
  886
  887sorted_by(Sort) -->
  888    html(' sorted by ~w'-[Sort]).
  889
  890
  891instance_table(Pairs, Options) -->
  892    { option(top_max(TopMax), Options, 500),
  893      option(top_max(BottomMax), Options, 500)
  894    },
  895    html_requires(css('rdf.css')),
  896    html(table(class(block),
  897               [ \instance_table_header
  898               | \table_rows_top_bottom(instance_row(Options), Pairs,
  899                                        TopMax, BottomMax)
  900               ])).
  901
  902instance_table_header -->
  903    html(tr([ th('Instance'),
  904              th('#Properties')
  905            ])).
  906
  907instance_row(Options, R-C) -->
  908    html([ td(\rdf_link(R, [role(inst)|Options])),
  909           td(class(int), C)
  910         ]).
  911
  912
  913                 /*******************************
  914                 *           PREDICATES         *
  915                 *******************************/
  916
  917%!  list_predicates(+Request)
  918%
  919%   List all predicates used in graph, sorted by label.
  920
  921list_predicates(Request) :-
  922    http_parameters(Request,
  923                    [ graph(Graph, [])
  924                    ]),
  925    findall(Pred, predicate_in_graph(Graph, Pred), Preds),
  926    sort_by_label(Preds, Sorted),
  927    reply_html_page(cliopatria(default),
  928                    title('Predicates in graph ~w'-[Graph]),
  929                    [ h1(['Predicates in graph ', \graph_link(Graph)]),
  930                      \predicate_table(Sorted, Graph, [])
  931                    ]).
  932
  933predicate_table(Preds, Graph, Options) -->
  934    { option(top_max(TopMax), Options, 500),
  935      option(bottom_max(BottomMax), Options, 500)
  936    },
  937    html_requires(css('rdf.css')),
  938    html(table(class(block),
  939               [ \predicate_table_header
  940               | \table_rows_top_bottom(predicate_row(Graph), Preds,
  941                                        TopMax, BottomMax)
  942               ])).
  943
  944predicate_table_header -->
  945    html(tr([ th('Predicate'),
  946              th('#Triples'),
  947              th('#Distinct subjects'),
  948              th('#Distinct objects'),
  949              th('Domain(s)'),
  950              th('Range(s)')
  951            ])).
  952
  953%!  predicate_row(?Graph, +Pred) is det.
  954
  955predicate_row(Graph, Pred) -->
  956    { predicate_statistics(Graph, Pred, Triples,
  957                           Subjects, Objects, Doms, Ranges),
  958      (   var(Graph)
  959      ->  Params = [predicate(Pred)]
  960      ;   Params = [graph(Graph), predicate(Pred)]
  961      ),
  962      http_link_to_id(list_triples,   Params, PLink)
  963    },
  964    html([ td(\rdf_link(Pred, [role(pred)])),
  965           td(class(int), a(href(PLink), Triples)),
  966           \resources(Subjects, subject, Params, [role(subj)]),
  967           \resources(Objects, object, Params, [role(obj)]),
  968           \resources(Doms, domain, Params, [role(domain)]),
  969           \resources(Ranges, range, Params, [role(range)])
  970         ]).
  971
  972resources([], _, _, _) -->
  973    !,
  974    html(td(class(empty), -)).
  975resources([One], _, _, Options) -->
  976    !,
  977    html(td(\rdf_link(One, Options))).
  978resources(Many, What, Params, _) -->
  979    !,
  980    { (   integer(Many)
  981      ->  Count = Many
  982      ;   length(Many, Count)
  983      ),
  984      http_link_to_id(list_predicate_resources, [side(What)|Params], Link)
  985    },
  986    html(td(class(int_c), a(href(Link), Count))).
  987
  988:- dynamic
  989    predicate_statistics_cache/8.  990
  991predicate_statistics(Graph, P, C, Subjects, Objects, Domains, Ranges) :-
  992    var(Graph),
  993    !,
  994    predicate_statistics_(Graph, P, C, Subjects, Objects, Domains, Ranges).
  995predicate_statistics(Graph, P, C, Subjects, Objects, Domains, Ranges) :-
  996    rdf_md5(Graph, MD5),
  997    predicate_statistics_cache(MD5, Graph, P, C,
  998                               Subjects, Objects, Domains, Ranges),
  999    !.
 1000predicate_statistics(Graph, P, C, Subjects, Objects, Domains, Ranges) :-
 1001    rdf_md5(Graph, MD5),
 1002    debug(rdf_browse, 'Recomputing pred stats for ~p in ~w, MD5=~w',
 1003          [P, Graph, MD5]),
 1004    retractall(predicate_statistics_cache(MD5, Graph, P, _,
 1005                                          _, _, _, _)),
 1006    predicate_statistics_(Graph, P, C, SubjectL, ObjectL, DomainL, RangeL),
 1007    res_summary(SubjectL, Subjects),
 1008    res_summary(ObjectL, Objects),
 1009    res_summary(DomainL, Domains),
 1010    res_summary(RangeL, Ranges),
 1011    assertz(predicate_statistics_cache(MD5, Graph, P, C,
 1012                                       Subjects, Objects, Domains, Ranges)).
 1013
 1014
 1015res_summary([], []) :- !.
 1016res_summary([One], [One]) :- !.
 1017res_summary(Many, Count) :-
 1018    length(Many, Count).
 1019
 1020
 1021predicate_statistics_(Graph, P, C, Subjects, Objects, Domains, Ranges) :-
 1022    findall(S-O, rdf(S,P,O,Graph), Pairs),
 1023    length(Pairs, C),
 1024    pairs_keys_values(Pairs, Ss, Os),
 1025    sort(Ss, Subjects),
 1026    sort(Os, Objects),
 1027    resources_types(Subjects, Graph, Domains),
 1028    resources_types(Objects, Graph, Ranges).
 1029
 1030resources_types(URIs, Graph, Types) :-
 1031    findall(T, resource_type_in(URIs, Graph, T), TList),
 1032    sort(TList, Types).
 1033
 1034resource_type_in(List, Graph, T) :-
 1035    member(URI, List),
 1036    resource_type(URI, Graph, T).
 1037
 1038%!  resource_type(+URI, +Graph, -Type) is multi.
 1039
 1040resource_type(literal(Lit), _, Type) :-
 1041    !,
 1042    (   Lit = type(Type, _)
 1043    ->  true
 1044    ;   rdf_equal(Type, rdfs:'Literal')
 1045    ).
 1046resource_type(^^(_, Type0), _, Type) :-
 1047    !,
 1048    Type = Type0.
 1049resource_type(@(_,_), _, Type) :-
 1050    !,
 1051    rdf_equal(Type, rdf:langString).
 1052resource_type(URI, Graph, Type) :-
 1053    (   string(URI)
 1054    ->  rdf_equal(Type, xsd:string)
 1055    ;   rdf(URI, rdf:type, Type, Graph)
 1056    *-> true
 1057    ;   rdf_equal(Type, rdfs:'Resource')
 1058    ).
 1059
 1060
 1061                 /*******************************
 1062                 *        LIST RESOURCES        *
 1063                 *******************************/
 1064
 1065%!  list_predicate_resources(+Request)
 1066%
 1067%   List resources related to a predicate.   The  _side_ argument is
 1068%   one of:
 1069%
 1070%       * subject
 1071%       Display all subject values for the predicate
 1072%       * object
 1073%       Display all object values for the predicate
 1074%       * domain
 1075%       Display the types of all subject values
 1076%       * range
 1077%       Display the types of all object values.
 1078%
 1079%   If the _skosmap_ attribute is =true=,   an extra column is added
 1080%   that shows SKOS concepts that match   literals.  This only makes
 1081%   sense if _side_ = =object= and (some) objects are literals.
 1082
 1083list_predicate_resources(Request) :-
 1084    http_parameters(Request,
 1085                    [ graph(Graph,
 1086                            [ optional(true),
 1087                              description('Limit search to this graph')
 1088                            ]),
 1089                      predicate(Pred,
 1090                                [ description('Predicate to list')
 1091                                ]),
 1092                      side(Which,
 1093                           [ oneof([subject,object,domain,range]),
 1094                             description('Relation to the predicate (see docs)')
 1095                           ]),
 1096                      sortBy(Sort,
 1097                             [ oneof([label,frequency]),
 1098                               default(frequency),
 1099                               description('How to sort results')
 1100                             ]),
 1101                      skosmap(SkosMap,
 1102                              [ boolean,
 1103                                optional(true),
 1104                                description('Show SKOS concepts for literals')
 1105                              ])
 1106                    ]),
 1107    do_skos(SkosMap, Which, Pred),
 1108    findall(R, predicate_resource(Graph, Pred, Which, R), Set),
 1109    term_frequency_list(Set, FPairs),
 1110    sort_pairs_by_label(FPairs, TableByName),
 1111    (   Sort == frequency
 1112    ->  reverse(TableByName, RevTableByName),
 1113        transpose_pairs(RevTableByName, FPairsUp),
 1114        reverse(FPairsUp, FPairsDown),
 1115        flip_pairs(FPairsDown, Table)
 1116    ;   Table = TableByName
 1117    ),
 1118
 1119    pred_resource_options(Pred, Which, Options),
 1120
 1121    reply_html_page(cliopatria(default),
 1122                    title(\resource_table_title(Graph, Pred, Which, Sort)),
 1123                    [ h1(\html_resource_table_title(Graph, Pred, Which,
 1124                                                    Sort, SkosMap)),
 1125                      \resource_frequency_table(Table,
 1126                                                [ skosmap(SkosMap),
 1127                                                  predicate(Pred),
 1128                                                  side(Which),
 1129                                                  sort(Sort)
 1130                                                | Options
 1131                                                ])
 1132                    ]).
 1133
 1134pred_resource_options(_, domain, [label('Class')]) :- !.
 1135pred_resource_options(_, range, [label('Class')]) :- !.
 1136pred_resource_options(_, _, []).
 1137
 1138do_skos(SkosMap, _, _) :-
 1139    nonvar(SkosMap),
 1140    !.
 1141do_skos(SkosMap, object, Pred) :-
 1142    \+ rdf(_, Pred, literal(_)),
 1143    !,
 1144    SkosMap = false.
 1145do_skos(SkosMap, object, _) :-
 1146    rdfs_individual_of(_, skos:'ConceptScheme'),
 1147    !,
 1148    SkosMap = true.
 1149do_skos(false, _, _).
 1150
 1151
 1152resource_table_title(Graph, Pred, Which, Sort) -->
 1153    { rdf_display_label(Pred, PLabel)
 1154    },
 1155    html('Distinct ~ws for ~w in ~w sorted by ~w'-
 1156         [Which, PLabel, Graph, Sort]
 1157         ).
 1158
 1159html_resource_table_title(Graph, Pred, Which, Sort, SkosMap) -->
 1160    html([ 'Distinct ~ws'-[Which],
 1161           \for_predicate(Pred),
 1162           \in_graph(Graph),
 1163           \sorted_by(Sort),
 1164           \showing_skosmap(SkosMap)
 1165         ]).
 1166
 1167for_predicate(Pred) -->
 1168    { var(Pred) },
 1169    !.
 1170for_predicate(Pred) -->
 1171    html([' for predicate ', \rdf_link(Pred, [role(pred)])]).
 1172
 1173showing_skosmap(true) -->
 1174    !,
 1175    html(' with mapping to SKOS').
 1176showing_skosmap(_) --> [].
 1177
 1178resource_frequency_table(Pairs, Options) -->
 1179    { option(top_max(TopMax), Options, 500),
 1180      option(top_max(BottomMax), Options, 500),
 1181      option(predicate(Pred), Options, _),
 1182      option(side(Side), Options)
 1183    },
 1184    html_requires(css('rdf.css')),
 1185    html(table(class(block),
 1186               [ \resource_table_header(Options)
 1187               | \table_rows_top_bottom(resource_row(Pred, Side, [role(pred)|Options]), Pairs,
 1188                                        TopMax, BottomMax)
 1189               ])).
 1190
 1191resource_table_header(Options) -->
 1192    { option(label(Label), Options, 'Resource'),
 1193      (   option(sort(Sort), Options)
 1194      ->  (   Sort == frequency
 1195          ->  A1 = [],
 1196              A2 = [class(sorted)]
 1197          ;   A1 = [class(sorted)],
 1198              A2 = []
 1199          )
 1200      ;   A1 = [],
 1201          A2 = []
 1202      )
 1203    },
 1204    html(tr([ th(A1, Label),
 1205              th(A2, 'Count'),
 1206              \skosmap_head(Options)
 1207            ])).
 1208
 1209skosmap_head(Options) -->
 1210    { option(skosmap(true), Options) },
 1211    !,
 1212    html(th('SKOS mapping')).
 1213skosmap_head(_) --> [].
 1214
 1215resource_row(Pred, object, Options, R-C) -->
 1216    !,
 1217    { object_param(R, Param),
 1218      http_link_to_id(list_triples_with_object,
 1219           [ p(Pred),
 1220             Param
 1221           ], HREF)
 1222    },
 1223    html([ td(\rdf_link(R, Options)),
 1224           td(class(int), a(href(HREF), C)),
 1225           \skosmap(R, Options)
 1226         ]).
 1227resource_row(Pred, Side, Options, R-C) -->
 1228    { domain_range_parameter(Side, R, Param),
 1229      !,
 1230      http_link_to_id(list_triples,
 1231           [ predicate(Pred),
 1232             Param
 1233           ], HREF)
 1234    },
 1235    html([ td(\rdf_link(R, Options)),
 1236           td(class(int), a(href(HREF), C)),
 1237           \skosmap(R, Options)
 1238         ]).
 1239resource_row(_, _, Options, R-C) -->
 1240    html([ td(\rdf_link(R, Options)),
 1241           td(class(int), C),
 1242           \skosmap(R, Options)
 1243         ]).
 1244
 1245object_param(R, r=R) :-
 1246    atom(R),
 1247    !.
 1248object_param(L, l=A) :-
 1249    term_to_atom(L, A).
 1250
 1251domain_range_parameter(domain, R, domain(R)).
 1252domain_range_parameter(range,  R, range(R)).
 1253
 1254%!  skosmap(+Literal, +Options)//
 1255%
 1256%   Component that emits a =td= cell with links to SKOS concepts
 1257%   that are labeled Literal.
 1258
 1259skosmap(Literal, Options) -->
 1260    { Literal = literal(_),
 1261      option(skosmap(true), Options),
 1262      findall(Concept-Scheme, skos_find(Literal, Concept, Scheme), Pairs),
 1263      Pairs \== [],
 1264      sort_pairs_by_label(Pairs, Sorted)
 1265    },
 1266    html(td(\skos_references(Sorted))).
 1267skosmap(_, _) --> [].
 1268
 1269skos_find(Literal, Concept, Scheme) :-
 1270    rdf_has(Concept, skos:prefLabel, Literal),
 1271    rdf_has(Concept, skos:inScheme, Scheme).
 1272
 1273skos_references([]) --> [].
 1274skos_references([H|T]) -->
 1275    skos_reference(H),
 1276    (   { T == [] }
 1277    ->  []
 1278    ;   html('; '),
 1279        skos_references(T)
 1280    ).
 1281
 1282skos_reference(Concept-Scheme) -->
 1283    html([\rdf_link(Concept, [role(concept)]), ' in ', \rdf_link(Scheme, [role(scheme)])]).
 1284
 1285
 1286flip_pairs([], []).
 1287flip_pairs([Key-Val|Pairs], [Val-Key|Flipped]) :-
 1288    flip_pairs(Pairs, Flipped).
 1289
 1290predicate_resource(Graph, Pred, subject, R) :-
 1291    !,
 1292    rdf(R, Pred, _, Graph).
 1293predicate_resource(Graph, Pred, object, R) :-
 1294    !,
 1295    rdf(_, Pred, R, Graph).
 1296predicate_resource(Graph, Pred, domain, D) :-
 1297    !,
 1298    rdf(R, Pred, _, Graph),
 1299    rdf(R, rdf:type, D, Graph).
 1300predicate_resource(Graph, Pred, range, R) :-
 1301    rdf(_, Pred, O, Graph),
 1302    resource_type(O, Graph, R).
 1303
 1304%!  term_frequency_list(+Terms, -TermFrequencyPairs)
 1305%
 1306%   TermFrequencyPairs is a list if  pairs Value-Count of equivalent
 1307%   term in Terms.  Equivalence is determined using ==/2.  The terms
 1308%   themselves are sorted on the standard order of terms.
 1309
 1310term_frequency_list(Resources, Pairs) :-
 1311    msort(Resources, Sorted),
 1312    fpairs(Sorted, Pairs).
 1313
 1314fpairs([], []).
 1315fpairs([H|T0], [H-C|T]) :-
 1316    pick_same(T0, T1, H, 1, C),
 1317    fpairs(T1, T).
 1318
 1319pick_same([H1|T0], L, H, F0, F) :-
 1320    H == H1,
 1321    !,
 1322    F1 is F0 + 1,
 1323    pick_same(T0, L, H, F1, F).
 1324pick_same(L, L, _, F, F).
 1325
 1326
 1327                 /*******************************
 1328                 *    LIST A SINGLE RESOURCE    *
 1329                 *******************************/
 1330
 1331%!  list_resource(+Request)
 1332%
 1333%   HTTP handler that lists the property table for a single resource
 1334%   (=local view)
 1335%
 1336%   @see    The functionality of this handler is also available as
 1337%           an embedable component through list_resource//2.
 1338
 1339list_resource(Request) :-
 1340    http_parameters(Request,
 1341                    [ r(URI,
 1342                        [ description('URI to describe')]),
 1343                      sorted(Sorted,
 1344                             [ oneof([default,none]),
 1345                               default(default),
 1346                               description('How to sort properties')
 1347                             ]),
 1348                      graph(Graph,
 1349                            [ optional(true),
 1350                              description('Limit to properties from graph')
 1351                            ]),
 1352                      resource_format(Format,
 1353                            [ default(DefaultFormat),
 1354                              atom,
 1355                              description('Display format as passed to rdf_link//2 ')
 1356                            ]),
 1357                      raw(Raw,
 1358                          [ default(false),
 1359                            boolean,
 1360                            description('If true, omit application hook')
 1361                          ])
 1362                    ]),
 1363    setting(resource_format, DefaultFormat),
 1364    rdf_display_label(URI, Label),
 1365    reply_html_page(cliopatria(default),
 1366                    title('Resource ~w'-[Label]),
 1367                    \list_resource(URI,
 1368                                   [ graph(Graph),
 1369                                     sorted(Sorted),
 1370                                     raw(Raw),
 1371                                     resource_format(Format)
 1372                                   ])).
 1373
 1374%!  list_resource(+URI, +Options)// is det.
 1375%
 1376%   Component that emits the `local view'   for  URI. The local view
 1377%   shows the basic properties  of  URI,   the  context  in which is
 1378%   appears and the graphs from which the information is extracted.
 1379%   Options is one of:
 1380%
 1381%       * graph(Graph)
 1382%       Limit properties in the table to the given graph
 1383%       * sorted(Sorted)
 1384%       One of =default= or =none=.
 1385%
 1386%   Calls the hook cliopatria:list_resource//2.  For compatibility
 1387%   reasons, it also tries the hook cliopatria:list_resource//1.
 1388%
 1389%   @see    list_resource/1 is the corresponding HTTP handler.  The
 1390%           component rdf_link//1 creates a link to list_resource/1.
 1391
 1392:- multifile
 1393    cliopatria:list_resource//1. 1394
 1395list_resource(URI, _Options) -->
 1396    { \+ rdf(URI, _, _),
 1397      \+ rdf(_, URI, _),
 1398      \+ rdf(_, _, URI),
 1399      \+ rdf(_, _, _, URI)
 1400    },
 1401    !,
 1402    html([ h1('Unknown URI'),
 1403           p(['The URI ', URI, ' does not appear in the graph, \c
 1404              neither as subject, predicate, object or graph.'])
 1405         ]).
 1406list_resource(URI, Options) -->
 1407    { \+ option(raw(true), Options) },
 1408    (   cliopatria:list_resource(URI, Options)
 1409    ->  []
 1410    ;   cliopatria:list_resource(URI) % deprecated
 1411    ).
 1412list_resource(URI, Options) -->
 1413    { option(graph(Graph), Options, _)
 1414    },
 1415    html([ h1([ 'Local view for "',
 1416                \location(URI, Graph), '"'
 1417              ]),
 1418           \define_prefix(URI),
 1419           \local_view(URI, Graph, Options),
 1420           p(\as_object(URI, Graph)),
 1421           p(\as_graph(URI)),
 1422           \uri_info(URI, Graph)
 1423         ]).
 1424
 1425%!  define_prefix(+URI)//
 1426%
 1427%   Allow defining a new prefix if the  resource is not covered by a
 1428%   prefix.
 1429
 1430define_prefix(URI) -->
 1431    { rdf_global_id(_Prefix:_Local, URI) },
 1432    !.
 1433define_prefix(URI) -->
 1434    { iri_xml_namespace(URI, Namespace, LocalName),
 1435      LocalName \== '',
 1436      http_link_to_id(add_prefix, [], Action)
 1437    },
 1438    html(form(action(Action),
 1439              ['No prefix for ', a(href(Namespace),Namespace), '. ',
 1440               \hidden(uri, Namespace),
 1441               input([name(prefix), size(8),
 1442                      title('Short unique abbreviation')
 1443                     ]),
 1444               input([type(submit), value('Add prefix')])
 1445              ])).
 1446define_prefix(_) -->                    % Not a suitable URI.  Warn?
 1447    [].
 1448
 1449
 1450%!  location(+URI, ?Graph) is det.
 1451%
 1452%   Show the URI. If the URI is a blank node, show its context using
 1453%   Turtle notation.
 1454
 1455location(URI, _Graph) -->
 1456    { rdf_is_bnode(URI),
 1457      !,
 1458      findall(Path, path_to_non_bnode(URI, Path), Paths),
 1459      sort_by_length(Paths, PathsByLen),
 1460      partition(starts_bnode, PathsByLen, StartsBNode, StartsReal),
 1461      (   StartsReal = [Path|_]
 1462      ->  true
 1463      ;   last(StartsBNode, Path)
 1464      )
 1465    },
 1466    bnode_location(Path).
 1467location(URI, _) -->
 1468    html(URI).
 1469
 1470bnode_location([P-URI]) -->
 1471    !,
 1472    html([ '[', \rdf_link(P,  [role(pred)]), ' ',
 1473                \rdf_link(URI,[role(bnode)]),
 1474           ']'
 1475         ]).
 1476bnode_location([P-URI|More]) -->
 1477    !,
 1478    html([ '[', div(class(bnode_attr),
 1479                    [ div(\rdf_link(P,  [ role(pred)])),
 1480                      div(\rdf_link(URI,[ role(bnode)]))
 1481                    ]), ' ',
 1482           \bnode_location(More),
 1483           ']'
 1484         ]).
 1485bnode_location([URI|More]) -->
 1486    !,
 1487    rdf_link(URI, [role(subj)]),
 1488    html(' '),
 1489    bnode_location(More).
 1490bnode_location([]) -->
 1491    [].
 1492
 1493path_to_non_bnode(URI, Path) :-
 1494    path_to_non_bnode_rev(URI, [URI], RevPath),
 1495    reverse(RevPath, Path).
 1496
 1497path_to_non_bnode_rev(URI, Seen, [P-URI|Path]) :-
 1498    (   rdf_is_bnode(URI),
 1499        rdf(S, P, URI),
 1500        \+ memberchk(S, Seen)
 1501    *-> path_to_non_bnode_rev(S, [S|Seen], Path)
 1502    ;   fail
 1503    ).
 1504path_to_non_bnode_rev(URI, _, [URI]).
 1505
 1506starts_bnode([URI|_]) :-
 1507    rdf_is_bnode(URI).
 1508
 1509sort_by_length(ListOfLists, ByLen) :-
 1510    map_list_to_pairs(length, ListOfLists, Pairs),
 1511    keysort(Pairs, Sorted),
 1512    pairs_values(Sorted, ByLen).
 1513
 1514%!  as_graph(+URI) is det.
 1515%
 1516%   Show the places where URI is used as a named graph
 1517
 1518as_graph(URI) --> { \+ rdf_graph(URI) }, !.
 1519as_graph(URI) -->
 1520    html([ 'This resource is also a ',
 1521           a([href(location_by_id(list_graph)+'?graph='+encode(URI))],
 1522             'named graph'),
 1523           '.']).
 1524
 1525
 1526%!  as_object(+URI, +Graph) is det.
 1527%
 1528%   Show the places where URI is used as an object.
 1529
 1530as_object(URI, Graph) -->
 1531    { findall(S-P, rdf(S,P,URI,Graph), Pairs),
 1532      sort(Pairs, Unique)
 1533    },
 1534    as_object_locations(Unique, URI, Graph).
 1535
 1536as_object_locations([], _URI, _) -->
 1537    !,
 1538    html([ 'The resource does not appear as an object' ]).
 1539as_object_locations([S-P], URI, _) -->
 1540    !,
 1541    html([ 'The resource appears as object in one triple:',
 1542           blockquote(class(triple),
 1543                      [ '{ ',
 1544                        \rdf_link(S, [role(subj)]), ', ',
 1545                        \rdf_link(P, [role(pred)]), ', ',
 1546                        \rdf_link(URI, [role(obj)]),
 1547                        ' }'
 1548                      ])
 1549         ]).
 1550as_object_locations(List, URI, Graph) -->
 1551    !,
 1552    { length(List, Len),
 1553      (   var(Graph)
 1554      ->  Extra = []
 1555      ;   Extra = [graph=Graph]
 1556      ),
 1557      http_link_to_id(list_triples_with_object, [r=URI|Extra], Link)
 1558    },
 1559    html([ 'The resource appears as object in ',
 1560           a(href(Link), [Len, ' triples'])
 1561         ]).
 1562
 1563%!  local_view(+URI, ?Graph, +Options) is det.
 1564%
 1565%   Show the local-view table for URI.  If Graph is given, only show
 1566%   triples from the given graph.  Options processed:
 1567%
 1568%       * top_max(+Count)
 1569%       * bottom_max(+Count)
 1570%       * sorted(+How)
 1571%       Defines the order of the predicates. One of =none=
 1572%       (database order) or =default=
 1573%       * show_graph(+Bool)
 1574%
 1575%   In addition, Options are passed to rdf_link//2.
 1576
 1577local_view(URI, Graph, Options) -->
 1578    { option(top_max(TopMax), Options, 500),
 1579      option(bottom_max(BottomMax), Options, 500),
 1580      po_pairs(URI, Graph, Pairs, Options),
 1581      lview_graphs(URI, Graph, Graphs)
 1582    },
 1583    (   { Pairs \== []
 1584        }
 1585    ->  html_requires(css('rdf.css')),
 1586        html(table(class(block),
 1587                   [ \lview_header(Options)
 1588                   | \table_rows_top_bottom(lview_row(Options, URI, Graphs),
 1589                                            Pairs,
 1590                                            TopMax, BottomMax)
 1591                   ])),
 1592        graph_footnotes(Graphs, Options)
 1593    ;   { lod_uri_graph(URI, LODGraph),
 1594          rdf_graph(LODGraph)
 1595        }
 1596    ->  html(p([ 'No triples for ', \show_link(URI), '. ',
 1597                 'Linked Data was loaded into ', \graph_link(LODGraph),
 1598                 '.'
 1599               ]))
 1600    ;   { sane_uri(URI) }
 1601    ->  { http_link_to_id(lod_crawl, [], FetchURL),
 1602          http_current_request(Request),
 1603          memberchk(request_uri(Here), Request)
 1604        },
 1605        html(form(action(FetchURL),
 1606                  [ \hidden(r, URI),
 1607                    \hidden(return_to, Here),
 1608                    'No triples for ', \show_link(URI),
 1609                    '.  Would you like to ',
 1610                    input([ type(submit),
 1611                            value('Query the Linked Data cloud')
 1612                          ]),
 1613                    '?'
 1614                  ]))
 1615    ;   html_requires(css('rdf.css')),
 1616        html(p([ 'No triples for ', \show_link(URI),
 1617                 ' (unknown URI scheme).']))
 1618    ).
 1619
 1620show_link(URI) -->
 1621    { sane_uri(URI) },
 1622    !,
 1623    html(a(href(URI), 'this URI')).
 1624show_link(URI) -->
 1625    html(span(class('insecure-uri'), URI)).
 1626
 1627sane_uri(URI) :-
 1628    uri_components(URI, Components),
 1629    uri_data(scheme, Components, Scheme),
 1630    valid_scheme(Scheme),
 1631    uri_data(authority, Components, Authority),
 1632    nonvar(Authority).
 1633
 1634valid_scheme(http).
 1635valid_scheme(https).
 1636valid_scheme(ftp).
 1637valid_scheme(ftps).
 1638
 1639lview_header(Options) -->
 1640    { option(sorted(Sorted), Options, default),
 1641      alt_sorted(Sorted, Alt),
 1642      http_current_request(Request),
 1643      http_reload_with_parameters(Request, [sorted(Alt)], HREF)
 1644    },
 1645    html(tr([ th('Predicate'),
 1646              th(['Value (sorted: ', a(href(HREF), Sorted), ')'])
 1647            ])).
 1648
 1649alt_sorted(default, none).
 1650alt_sorted(none, default).
 1651
 1652
 1653lview_row(Options, S, Graphs, P-OList) -->
 1654    html([ td(class(predicate), \rdf_link(P, [role(pred)|Options])),
 1655           td(class(object), \object_list(OList, S, P, Graphs, Options, 1))
 1656         ]).
 1657
 1658object_list([], _, _, _, _, _) --> [].
 1659object_list([H|T], S, P, Graphs, Options, Row) -->
 1660    { NextRow is Row + 1,
 1661      obj_class(Row, Class)
 1662    },
 1663    html(div(class(Class),
 1664             [ \rdf_link(H, [role(obj)|Options]),
 1665               \graph_marks(S, P, H, Graphs)
 1666             ])),
 1667    object_list(T, S, P, Graphs, Options, NextRow).
 1668
 1669obj_class(N, Class) :-
 1670    (   N mod 2 =:= 0
 1671    ->  Class = even
 1672    ;   Class = odd
 1673    ).
 1674
 1675graph_marks(_,_,_,[_]) --> !.
 1676graph_marks(S,P,O,Graphs) -->
 1677    html(sup(class(graph), \graphs(S,P,O,Graphs))).
 1678
 1679graphs(S, P, O, Graphs) -->
 1680    { findall(G, rdf(S,P,O,G:_), GL) },
 1681    graphs(GL, Graphs).
 1682
 1683graphs([], _) --> [].
 1684graphs([H|T], Graphs) -->
 1685    { nth1(N, Graphs, H) -> true },
 1686    html(N),
 1687    (   { T == [] }
 1688    ->  []
 1689    ;   html(','),
 1690        graphs(T, Graphs)
 1691    ).
 1692
 1693%!  graph_footnotes(+GraphList, +Options)//
 1694%
 1695%   Describe footnote marks in the local   view  table that indicate
 1696%   the origin of triples.
 1697
 1698graph_footnotes([], _Options) --> !.
 1699graph_footnotes([Graph], _Options) -->
 1700    !,
 1701    html(p(class('graphs-used'),
 1702           [ 'All properties reside in the graph ',
 1703             \graph_link(Graph)
 1704           ])).
 1705graph_footnotes(Graphs, Options) -->
 1706    html(p(class('graphs-used'),
 1707           'Named graphs describing this resource:')),
 1708    graph_footnotes(Graphs, 1, Options).
 1709
 1710graph_footnotes([], _, _) --> [].
 1711graph_footnotes([H|T], N, Options) -->
 1712    html(div(class('graph-fn'),
 1713             [ sup(class(graph), N),
 1714               \graph_link(H)
 1715             ])),
 1716    { N2 is N + 1 },
 1717    graph_footnotes(T, N2, Options).
 1718
 1719%!  lview_graphs(+Subject, ?Graph, -Graphs) is det.
 1720
 1721lview_graphs(_Subject, Graph, Graphs) :-
 1722    nonvar(Graph),
 1723    !,
 1724    Graphs = [Graph].
 1725lview_graphs(Subject, Graph, Graphs) :-
 1726    findall(Graph, rdf(Subject, _, _, Graph:_), Graphs0),
 1727    sort(Graphs0, Graphs).
 1728
 1729%!  po_pairs(+Subject, ?Graph, -Pairs, +Options) is det.
 1730%
 1731%   Pairs is a  list  of  P-ObjectList   for  the  S,P,O  triples on
 1732%   Subject. The list is normally sorted  by predicate as defined by
 1733%   p_order/2 below.
 1734
 1735po_pairs(S, Graph, Pairs, Options) :-
 1736    option(sorted(none), Options),
 1737    !,
 1738    findall(P-[O], rdf(S,P,O,Graph), Pairs).
 1739po_pairs(S, Graph, Pairs, _Options) :-
 1740    var(Graph),
 1741    !,
 1742    findall(P-OL,
 1743            setof(O, rdf(S,P,O), OL),
 1744            Pairs0),
 1745    sort_po(Pairs0, Pairs).
 1746po_pairs(S, Graph, Pairs, _Options) :-
 1747    findall(P-OL,
 1748            setof(O, rdf(S,P,O,Graph), OL),
 1749            Pairs0),
 1750    sort_po(Pairs0, Pairs).
 1751
 1752%!  sort_po(+Pairs, -Sorted) is det.
 1753%
 1754%   Sort a list of P-ValueList. This is   used  to keep the dominant
 1755%   rdf, rdfs, skos, etc. properties in a   fixed order at the start
 1756%   of the table.
 1757
 1758sort_po(Pairs, Sorted) :-
 1759    map_list_to_pairs(po_key, Pairs, Keyed),
 1760    keysort(Keyed, KeySorted),
 1761    exclude(=(0-_), KeySorted, Remaining),
 1762    pairs_values(Remaining, Sorted).
 1763
 1764po_key(P-_, Key) :-
 1765    p_order(P, Key),
 1766    !.
 1767po_key(P-_, Key) :-
 1768    label_sort_key(P, Key).
 1769
 1770%!  p_order(+P, -SortKey) is semidet.
 1771%
 1772%   SortKey is the key used for sorting the predicate P.
 1773%
 1774%   @tbd    Make this hookable.
 1775
 1776:- rdf_meta
 1777    p_order(r,?). 1778
 1779p_order(P, Order) :-
 1780    cliopatria:predicate_order(P, Order),
 1781    !.
 1782p_order(P, 100) :-
 1783    label_property(P),
 1784    !.
 1785p_order(P, 110) :-
 1786    rdfs_subproperty_of(P, skos:altLabel),
 1787    !.
 1788p_order(rdf:type,         210).
 1789p_order(rdfs:subClassOf,  220).
 1790p_order(rdfs:domain,      230).
 1791p_order(rdfs:range,       240).
 1792p_order(rdfs:comment,     310).
 1793p_order(rdfs:isDefinedBy, 320).
 1794
 1795
 1796%!  uri_info(+URI, +Graph)// is det.
 1797%
 1798%   Display additional info and actions about   a URI in the context
 1799%   of the given graph.
 1800
 1801uri_info(URI, Graph) -->
 1802    uri_class_info(URI, Graph),
 1803    uri_predicate_info(URI, Graph),
 1804    html(h2('Context graph')),
 1805    context_graph(URI, []).
 1806
 1807uri_class_info(URI, Graph) -->
 1808    { rdf_current_predicate(URI)
 1809    },
 1810    !,
 1811    html(h2('Predicate statistics')),
 1812    predicate_table([URI], Graph, []).
 1813uri_class_info(_,_) --> [].
 1814
 1815uri_predicate_info(URI, Graph) -->
 1816    { \+ \+ rdf(_, rdf:type, URI, Graph)
 1817    },
 1818    !,
 1819    html(h2('Class statistics')),
 1820    class_table([URI], Graph, []).
 1821uri_predicate_info(_, _) --> [].
 1822
 1823
 1824%!  context_graph(+URI, +Options)// is det.
 1825%
 1826%   Show graph with  the  context  of   URI.  Options  is  passed to
 1827%   cliopatria:context_graph/3  and  cliopatria:node_shape/3.    Two
 1828%   options have special meaning:
 1829%
 1830%       * style(?Style)
 1831%       If this option is not specified, it is passed as a variable.
 1832%       It can be tested or filled by cliopatria:context_graph/3 and
 1833%       subsequently used by cliopatria:node_shape/3.
 1834%
 1835%       * start(+URI)
 1836%       Passed to cliopatria:node_shape/3 to indicate the origin of
 1837%       the context graph.
 1838
 1839context_graph(URI, Options) -->
 1840    { merge_options(Options, [style(_)], GraphOption),
 1841      rdf_equal(owl:sameAs, SameAs)
 1842    },
 1843    html([ \graphviz_graph(context_graph(URI, GraphOption),
 1844                           [ object_attributes([width('100%')]),
 1845                             wrap_url(resource_link),
 1846                             graph_attributes([ rankdir('RL')
 1847                                              ]),
 1848                             shape_hook(shape(URI, GraphOption)),
 1849                             bag_shape_hook(bag_shape(GraphOption)),
 1850                             edge_hook(edge(URI, GraphOption)),
 1851                             label_hook(cliopatria:node_label),
 1852                             smash([SameAs])
 1853                           ])
 1854         ]).
 1855
 1856:- public
 1857    shape/5,
 1858    edge/5,
 1859    bag_shape/3. 1860
 1861%!  shape(+Start, +Options, +URI, -Shape, +GVOptions) is semidet.
 1862%
 1863%   Specify GraphViz shape for URI. This   predicate  calls the hook
 1864%   cliopatria:node_shape/3.
 1865
 1866shape(Start, Options, URI, Shape, GVOptions) :-
 1867    append(Options, GVOptions, AllOptions),
 1868    cliopatria:node_shape(URI, Shape, [start(Start)|AllOptions]),
 1869    !.
 1870shape(Start, _Options, Start,
 1871      [ shape(tripleoctagon),style(filled),fillcolor('#ff85fd'),id(start) ],
 1872      _GVOptions).
 1873
 1874%!  bag_shape(+Options, +Members, -Shape) is semidet.
 1875%
 1876%   Compute properties for a bag
 1877
 1878bag_shape(Options, Members, Shape) :-
 1879    cliopatria:bag_shape(Members, Shape, Options),
 1880    !.
 1881bag_shape(_, _, []).
 1882
 1883edge(Start, Options, Predicate, Shape, GVOptions) :-
 1884    append(Options, GVOptions, AllOptions),
 1885    cliopatria:edge_shape(Predicate, Shape, [start(Start)|AllOptions]),
 1886    !.
 1887
 1888%!  context_graph(+URI, -Triples, +Options) is det.
 1889%
 1890%   Triples is a graph  that  describes   the  environment  of  URI.
 1891%   Currently, the environment is defined as:
 1892%
 1893%       * skos:related properties (using 1 step)
 1894%       * Transitive properties (using upto 3 steps).
 1895%
 1896%   This predicate can be hooked using cliopatria:context_graph/2.
 1897
 1898context_graph(URI, Options, RDF) :-
 1899    cliopatria:context_graph(URI, RDF, Options),
 1900    !.
 1901context_graph(URI, _Options, RDF) :-            % Compatibility
 1902    cliopatria:context_graph(URI, RDF),
 1903    !.
 1904context_graph(URI, _, RDF) :-
 1905    findall(T, context_triple(URI, T), RDF0),
 1906    sort(RDF0, RDF1),
 1907    minimise_graph(RDF1, RDF2),             % remove inverse/symmetric/...
 1908    bagify_graph(RDF2, RDF3, Bags, []),     % Create bags of similar resources
 1909    append(RDF3, Bags, RDF).
 1910
 1911:- rdf_meta
 1912    transitive_context(r),
 1913    context(r). 1914
 1915context_triple(URI, Triple) :-
 1916    transitive_context(CP),
 1917    parents(URI, CP, Triples, [URI], 3),
 1918    member(Triple, Triples).
 1919context_triple(URI, Triple) :-
 1920    cliopatria:context_predicate(URI, R),
 1921    rdf_has(URI, R, O, P),
 1922    normalize_triple(rdf(URI, P, O), Triple).
 1923context_triple(URI, Triple) :-
 1924    context(R),
 1925    rdf_has(URI, R, O, P),
 1926    normalize_triple(rdf(URI, P, O), Triple).
 1927context_triple(URI, Triple) :-
 1928    context(R),
 1929    rdf_has(S, R, URI, P),
 1930    normalize_triple(rdf(S, P, URI), Triple).
 1931
 1932normalize_triple(rdf(S, inverse_of(P0), O),
 1933                 rdf(O, P, S)) :-
 1934    !,
 1935    rdf_predicate_property(P0, inverse_of(P)).
 1936normalize_triple(RDF, RDF).
 1937
 1938
 1939
 1940parents(URI, Up, [Triple|T], Visited, MaxD) :-
 1941    succ(MaxD2, MaxD),
 1942    rdf_has(URI, Up, Parent, P),
 1943    normalize_triple(rdf(URI, P, Parent), Triple),
 1944    \+ memberchk(Parent, Visited),
 1945    parents(Parent, Up, T, [Parent|Visited], MaxD2).
 1946parents(_, _, [], _, _).
 1947
 1948transitive_context(owl:sameAs).
 1949transitive_context(rdfs:subClassOf).
 1950transitive_context(rdfs:subPropertyOf).
 1951transitive_context(skos:broader).
 1952transitive_context(P) :-
 1953    rdfs_individual_of(P, owl:'TransitiveProperty'),
 1954    rdf_predicate_property(P, rdfs_subject_branch_factor(BF)),
 1955    BF < 2.0.
 1956
 1957context(skos:related).
 1958context(skos:mappingRelation).
 1959
 1960%!  list_triples(+Request)
 1961%
 1962%   List  triples  for  a  given    predicate.  The  triple-set  can
 1963%   optionally be filtered on the graph, type of the subject or type
 1964%   of the object.
 1965
 1966list_triples(Request) :-
 1967    http_parameters(Request,
 1968                    [ predicate(P,
 1969                                [ optional(true),
 1970                                  description('Limit triples to this pred')]),
 1971                      graph(Graph, [ optional(true),
 1972                                     description('Limit triples to this graph')
 1973                                   ]),
 1974                      domain(Dom,  [ optional(true),
 1975                                     description('Restrict to subjects of this class')
 1976                                   ]),
 1977                      range(Range, [ optional(true),
 1978                                     description('Restrict to objects of this class')
 1979                                   ])
 1980                    ]),
 1981    (   atom(Dom)
 1982    ->  findall(rdf(S,P,O), rdf_in_domain(S,P,O,Dom,Graph), Triples0)
 1983    ;   atom(Range)
 1984    ->  findall(rdf(S,P,O), rdf_in_range(S,P,O,Range,Graph), Triples0)
 1985    ;   findall(rdf(S,P,O), rdf(S,P,O,Graph), Triples0)
 1986    ),
 1987    sort(Triples0, Triples),
 1988    sort_triples_by_label(Triples, Sorted),
 1989    length(Sorted, Count),
 1990    (   var(P)
 1991    ->  Title = 'Triples in graph ~w'-[Graph]
 1992    ;   rdf_display_label(P, PLabel),
 1993        Title = 'Triples for ~w in graph ~w'-[PLabel, Graph]
 1994    ),
 1995    reply_html_page(cliopatria(default),
 1996                    title(Title),
 1997                    [ h1(\triple_header(Count, P, Dom, Range, Graph)),
 1998                      \triple_table(Sorted, P, [resource_format(nslabel)])
 1999                    ]).
 2000
 2001rdf_in_domain(S,P,O,Dom,Graph) :-
 2002    rdf(S, P, O, Graph),
 2003    rdf_has(S, rdf:type, Dom).
 2004
 2005rdf_in_range(S,P,O,Lit,Graph) :-
 2006    rdf_equal(rdfs:'Literal', Lit),
 2007    !,
 2008    O = literal(_),
 2009    rdf(S, P, O, Graph).
 2010rdf_in_range(S,P,O,Rng,Graph) :-
 2011    rdf_equal(rdfs:'Resource', Rng),
 2012    !,
 2013    rdf(S, P, O, Graph),
 2014    atom(O).
 2015rdf_in_range(S,P,O,Rng,Graph) :-
 2016    rdf(S, P, O, Graph),
 2017    rdf_has(O, rdf:type, Rng).
 2018
 2019
 2020triple_header(Count, Pred, Dom, Range, Graph) -->
 2021    html([ 'Table for the ~D triples'-[Count],
 2022           \for_predicate(Pred),
 2023           \with_domain(Dom),
 2024           \with_range(Range),
 2025           \in_graph(Graph)
 2026         ]).
 2027
 2028with_domain(Dom) -->
 2029    { var(Dom) },
 2030    !.
 2031with_domain(Dom) -->
 2032    html([' with domain ', \rdf_link(Dom, [role(domain)])]).
 2033
 2034with_range(Range) -->
 2035    { var(Range) },
 2036    !.
 2037with_range(Range) -->
 2038    html([' with range ', \rdf_link(Range, [role(range)])]).
 2039
 2040%!  triple_table(+Triples, +Predicate, +Options)// is det.
 2041%
 2042%   Show a list  of  triples.  If   Predicate  is  given,  omit  the
 2043%   predicate from the table.
 2044
 2045triple_table(Triples, Pred, Options) -->
 2046    { option(top_max(TopMax), Options, 500),
 2047      option(top_max(BottomMax), Options, 500)
 2048    },
 2049    html(table(class(block),
 2050               [ \spo_header(Pred)
 2051               | \table_rows_top_bottom(spo_row(Options, Pred), Triples,
 2052                                        TopMax, BottomMax)
 2053               ])).
 2054
 2055spo_header(P) -->
 2056    { nonvar(P) },
 2057    html(tr([ th('Subject'),
 2058              th('Object')
 2059            ])).
 2060spo_header(_) -->
 2061    html(tr([ th('Subject'),
 2062              th('Predicate'),
 2063              th('Object')
 2064            ])).
 2065
 2066spo_row(Options, Pred, rdf(S,_,O)) -->
 2067    { nonvar(Pred) },
 2068    !,
 2069    html([ td(class(subject), \rdf_link(S, [role(subj)|Options])),
 2070           td(class(object),  \rdf_link(O, [role(obj) |Options]))
 2071         ]).
 2072spo_row(Options, _, rdf(S,P,O)) -->
 2073    html([ td(class(subject),   \rdf_link(S, [role(subj)|Options])),
 2074           td(class(predicate), \rdf_link(P, [role(pred)|Options])),
 2075           td(class(object),    \rdf_link(O, [role(obj) |Options]))
 2076         ]).
 2077
 2078
 2079%!  list_triples_with_object(+Request)
 2080%
 2081%   HTTP handler that creates a  subject/predicate table for triples
 2082%   that have the gived _object_. Object   is specified using either
 2083%   the =r= or =l= parameter. Optionally,  results can be limited to
 2084%   a predicate and/or graph.
 2085
 2086list_triples_with_object(Request) :-
 2087    http_parameters(Request,
 2088                    [ r(RObject,   [optional(true),
 2089                                    description('Object as resource (URI)')
 2090                                   ]),
 2091                      l(LObject,   [optional(true),
 2092                                    description('Object as literal (Prolog notation)')
 2093                                   ]),
 2094                      p(P,         [optional(true),
 2095                                    description('Limit to a given predicate (URI)')
 2096                                   ]),
 2097                      graph(Graph, [optional(true),
 2098                                    description('Limit to a given graph (URI)')
 2099                                   ]),
 2100                      sortBy(Sort,
 2101                             [ oneof([label, subject, predicate]),
 2102                               default(label),
 2103                               description('How to sort the result')
 2104                             ])
 2105                    ]),
 2106    target_object(RObject, LObject, Object),
 2107    list_triples_with_object(Object, P, Graph, [sortBy(Sort)]).
 2108
 2109target_object(RObject, _LObject, RObject) :-
 2110    atom(RObject),
 2111    !.
 2112target_object(_, LObject, Object) :-
 2113    atom(LObject),
 2114    !,
 2115    term_to_atom(Object0, LObject),
 2116    rdf11_rdf_db(Object0, Object).
 2117target_object(_, _, _) :-
 2118    throw(existence_error(http_parameter, r)).
 2119
 2120rdf11_rdf_db(^^(String, Type), literal(type(Type, Atom))) :-
 2121    atom_string(Atom, String).
 2122rdf11_rdf_db(@(String, Lang), literal(lang(Lang, Atom))) :-
 2123    atom_string(Atom, String).
 2124rdf11_rdf_db(literal(Lit),   literal(Lit)).
 2125
 2126
 2127%!  list_triples_with_literal(+Request)
 2128%
 2129%   List triples that have a literal   that matches the q-parameter.
 2130%   This is used for  finding   objects  through  the autocompletion
 2131%   interface.
 2132
 2133list_triples_with_literal(Request) :-
 2134    http_parameters(Request,
 2135                    [ q(Text,
 2136                        [optional(true),
 2137                         description('Object as resource (URI)')
 2138                        ])
 2139                    ]),
 2140    list_triples_with_object(literal(Text), _, _, [sortBy(subject)]).
 2141
 2142
 2143list_triples_with_object(Object, P, Graph, Options) :-
 2144    findall(S-P, rdf(S,P,Object,Graph), Pairs),
 2145    (   option(sortBy(label), Options)
 2146    ->  sort_pairs_by_label(Pairs, Sorted)
 2147    ;   option(sortBy(predicate), Options)
 2148    ->  transpose_pairs(Pairs, Transposed), % flip pairs and sort on new key
 2149        flip_pairs(Transposed, Sorted)      % flip back without sort
 2150    ;   sort(Pairs, Sorted)
 2151    ),
 2152    length(Pairs, Count),
 2153    label_of(Object, OLabel),
 2154    reply_html_page(cliopatria(default),
 2155                    title('Triples with object ~w'-[OLabel]),
 2156                    [ h1(\otriple_header(Count, Object, P, Graph, Options)),
 2157                      \otriple_table(Sorted, Object, [resource_format(nslabel)])
 2158                    ]).
 2159
 2160otriple_header(Count, Object, Pred, Graph, Options) -->
 2161    { option(sortBy(SortBy), Options) },
 2162    html([ 'Table for the ~D triples'-[Count],
 2163           \with_object(Object),
 2164           \on_predicate(Pred),
 2165           \in_graph(Graph),
 2166           \sorted_by(SortBy)
 2167         ]).
 2168
 2169with_object(Obj) -->
 2170    { var(Obj)},
 2171    !.
 2172with_object(Obj) -->
 2173    html([' with object ', \rdf_link(Obj, [role(obj)])]).
 2174
 2175on_predicate(P) -->
 2176    { var(P) },
 2177    !.
 2178on_predicate(P) -->
 2179    html([' on predicate ', \rdf_link(P, [role(pred)])]).
 2180
 2181
 2182otriple_table(SPList, Object, Options) -->
 2183    { option(top_max(TopMax), Options, 500),
 2184      option(top_max(BottomMax), Options, 500)
 2185    },
 2186    html(table(class(block),
 2187               [ \sp_header(Object)
 2188               | \table_rows_top_bottom(sp_row(Options,Object), SPList,
 2189                                        TopMax, BottomMax)
 2190               ])).
 2191
 2192sp_header(_) -->
 2193    html(tr([ th('Subject'),
 2194              th('Predicate')
 2195            ])).
 2196
 2197sp_row(Options, _O, S-P) -->
 2198    html([ td(class(subject),   \rdf_link(S, [role(subj)|Options])),
 2199           td(class(predicate), \rdf_link(P, [role(pred)|Options]))
 2200         ]).
 2201
 2202
 2203
 2204
 2205
 2206                 /*******************************
 2207                 *            RDF UTIL          *
 2208                 *******************************/
 2209
 2210%!  sort_by_label(+URIs, -Sorted) is det.
 2211%
 2212%   Sort a list of URIs by their label using locale-based ordering.
 2213
 2214sort_by_label(URIs, Sorted) :-
 2215    map_list_to_pairs(label_sort_key, URIs, LabelPairs),
 2216    keysort(LabelPairs, SortedPairs),
 2217    pairs_values(SortedPairs, Sorted).
 2218
 2219label_sort_key(URI, Key) :-
 2220    label_of(URI, Label),
 2221    (   atom(Label)
 2222    ->  collation_key(Label, Key)
 2223    ;   Key = Label
 2224    ).
 2225
 2226label_of(URI, Label) :-
 2227    rdf_is_resource(URI),
 2228    !,
 2229    rdf_display_label(URI, Label).
 2230label_of(Literal, Label) :-
 2231    literal_text(Literal, Label).
 2232
 2233
 2234%!  sort_triples_by_label(+Triples, -Sorted)
 2235%
 2236%   Sort a list of rdf(S,P,O) by the labels.
 2237
 2238sort_triples_by_label(Pairs, Sorted) :-
 2239    map_list_to_pairs(key_triple_by_label, Pairs, LabelPairs),
 2240    keysort(LabelPairs, SortedPairs),
 2241    pairs_values(SortedPairs, Sorted).
 2242
 2243key_triple_by_label(rdf(S,P,O), rdf(SK,PK,OK)) :-
 2244    label_sort_key(S, SK),
 2245    label_sort_key(P, PK),
 2246    label_sort_key(O, OK).
 2247
 2248%!  sort_pairs_by_label(+Pairs, -Sorted)
 2249%
 2250%   Sort a pair-list where the keys are resources by their label.
 2251
 2252sort_pairs_by_label(Pairs, Sorted) :-
 2253    map_list_to_pairs(key_label_sort_key, Pairs, LabelPairs),
 2254    keysort(LabelPairs, SortedPairs),
 2255    pairs_values(SortedPairs, Sorted).
 2256
 2257key_label_sort_key(R-_, Key) :-
 2258    label_sort_key(R, Key).
 2259
 2260
 2261                 /*******************************
 2262                 *        CUSTOMIZATION         *
 2263                 *******************************/
 2264
 2265%!  p_label(+Id, -Label)
 2266%
 2267%   Defines the visible label for a property.
 2268%
 2269%   @see    html_property_table//2.
 2270
 2271p_label(source(_), 'Source URL').
 2272p_label(triples(G),
 2273        ['# ', a(href(Link), triples)]) :-
 2274    http_link_to_id(list_triples, [graph=G], Link).
 2275p_label(subject_count(G),
 2276        ['# ', a(href(Link), subjects)]) :-
 2277    http_link_to_id(list_instances, [graph=G], Link).
 2278p_label(bnode_count(G),
 2279        ['# ', a(href(Link), 'bnode subjects')]) :-
 2280    http_link_to_id(list_instances, [graph=G, type=bnode], Link).
 2281p_label(predicate_count(G),
 2282        ['# ', a(href(Link), predicates)]) :-
 2283    http_link_to_id(list_predicates, [graph=G], Link).
 2284p_label(type_count(G),
 2285        ['# Referenced ', a(href(Link), classes)]) :-
 2286    http_link_to_id(list_classes, [graph=G], Link).
 2287
 2288
 2289                 /*******************************
 2290                 *            SEARCH            *
 2291                 *******************************/
 2292
 2293%!  search(+Request)
 2294%
 2295%   HTTP handler to search for triples   that contain a literal that
 2296%   matches a query.
 2297%
 2298%   @tbd    Produce a sensible search language.
 2299
 2300search(Request) :-
 2301    http_parameters(Request,
 2302                    [ q(QueryText,
 2303                        [ description('Query to search for')
 2304                        ]),
 2305                      filter(FilterAtom,
 2306                             [ optional(true),
 2307                               description('Filter on raw matches (a Prolog term)')
 2308                             ])
 2309                    ]),
 2310    (   var(FilterAtom)
 2311    ->  Filter = true
 2312    ;   atom_to_term(FilterAtom, Filter0, []),
 2313        rdf_global_term(Filter0, Filter)
 2314    ),
 2315
 2316    find_literals(QueryText, Literals, Query),
 2317    literal_triples(Literals, Filter, Triples),
 2318    reply_html_page(cliopatria(default),
 2319                    title('Search results for ~q'-[Query]),
 2320                    [ h1('Search results for token "~q"'-[Query]),
 2321                      \rdf_table(Triples, [])
 2322                    ]).
 2323
 2324find_literals(QueryText, [Query], exact(Query)) :-
 2325    % Check if Q starts and ends with double quotes:
 2326    sub_atom(QueryText,0,1,Remainder,'"'),
 2327    sub_atom(QueryText,Remainder,1,0,'"'),
 2328    !,
 2329    sub_atom(QueryText,1,_,1,Query).
 2330find_literals(QueryText, Literals, Query) :-
 2331    % if not quoted, perform search on tokenized query
 2332    tokenize_atom(QueryText, Tokens),
 2333    once(phrase(query(Query), Tokens)),
 2334    rdf_find_literals(Query, Literals).
 2335
 2336query(Query) -->
 2337    simple_query(Q1),
 2338    (   eos
 2339    ->  {Query = Q1}
 2340    ;   query(Q2),
 2341        {Query = and(Q1,Q2)}
 2342    ).
 2343
 2344eos([],[]).
 2345
 2346simple_query(Token) -->
 2347    ['"',Token,'"'],
 2348    !.
 2349simple_query(not(Token)) -->
 2350    [-, Token].
 2351simple_query(case(Token)) -->
 2352    [Token].
 2353
 2354%!  literal_triples(+ListOfLiterals, +Filter, -Triples) is det.
 2355%
 2356%   Find the list of triples with   a  literal in ListOfLiterals and
 2357%   whose subject satisfies Filter.
 2358
 2359literal_triples(Literals, Filter, Triples) :-
 2360    sub_term(graph(Graph), Filter),
 2361    !,
 2362    phrase(ltriples(Literals, Graph, Filter), Triples).
 2363literal_triples(Literals, Filter, Triples) :-
 2364    phrase(ltriples(Literals, Filter), Triples).
 2365
 2366
 2367ltriples([], _, _) --> [].
 2368ltriples([H|T], G, F) -->
 2369    findall(rdf(S,P,literal(L)),
 2370            (   rdf(S,P,literal(exact(H), L),G),
 2371                search_filter(F, S)
 2372            )),
 2373    ltriples(T, G, F).
 2374
 2375ltriples([], _) --> [].
 2376ltriples([H|T], F) -->
 2377    findall(rdf(S,P,literal(L)),
 2378            (   rdf(S,P,literal(exact(H), L)),
 2379                search_filter(F, S)
 2380            )),
 2381    ltriples(T, F).
 2382
 2383%!  rdf_table(+Triples, +Options)// is det.
 2384%
 2385%   Emit a table of triples.
 2386%
 2387%   @param Triples is a list of rdf(S,P,O).
 2388
 2389rdf_table(Triples, Options) -->
 2390    { option(top_max(TopMax), Options, 500),
 2391      option(top_max(BottomMax), Options, 500)
 2392    },
 2393    html(table(class(block),
 2394               [ tr([ th('Subject'), th('Predicate'), th('Object') ])
 2395               | \table_rows_top_bottom(triple, Triples,
 2396                                        TopMax, BottomMax)
 2397               ])).
 2398
 2399triple(rdf(S,P,O)) -->
 2400    html([ td(class(subject),   \rdf_link(S, [role(subj)])),
 2401           td(class(predicate), \rdf_link(P, [role(pred)])),
 2402           td(class(object),    \rdf_link(O, [role(obj) ]))
 2403         ]).
 2404
 2405
 2406                 /*******************************
 2407                 *     HTML INFRASTRUCTURE      *
 2408                 *******************************/
 2409
 2410%!  html_property_table(+Template, :Goal)// is det.
 2411%
 2412%   Create a table for all instantiations of Template for which Goal
 2413%   is true. Template is a term row(C1,   C2, ...). The first column
 2414%   (C1) is considered the property-name and   emitted  as a cell of
 2415%   class =p_name=. The label for  the   property  is  derived using
 2416%   p_label/2. The remainder is emited as normal td value-cells.
 2417
 2418html_property_table(Template, Goal) -->
 2419    { findall(Template, Goal, Rows) },
 2420    html(table(class(block),
 2421               \table_rows(prow, Rows))).
 2422
 2423prow(Row) -->
 2424    { Row =.. [_,H|Cells],
 2425      (   p_label(H, Label0)
 2426      ->  true
 2427      ;   functor(H, Label0, _)
 2428      ),
 2429      (   is_list(Label0)
 2430      ->  append(Label0, [:], Label)
 2431      ;   Label = [Label0, :]
 2432      )
 2433    },
 2434    html([ th(class(p_name), Label)
 2435         | \pcells(Cells)
 2436         ]).
 2437
 2438pcells([]) --> [].
 2439pcells([H|T]) -->
 2440    pcell(H),
 2441    pcells(T).
 2442
 2443pcell(int(Value)) -->
 2444    { integer(Value) },
 2445    !,
 2446    nc('~D', Value).
 2447pcell(H) -->
 2448    { compound(H),
 2449      H =.. [Class,Value], !
 2450    },
 2451    html(td(class(Class), Value)).
 2452pcell(H) -->
 2453    html(td(H)).
 2454
 2455
 2456%!  table_rows(:Goal, +DataList)// is det.
 2457%!  table_rows(:Goal, +DataList, +MaxTop, +MaxBottom)// is det.
 2458%
 2459%   Emit a number of table rows (=tr=).   The content of each row is
 2460%   created by calling call(Goal, Data)  as   a  DCG.  The rows have
 2461%   alternating classes =even= and =odd=.  The first row is =odd=.
 2462%
 2463%   The variation table_rows//4  limits  the   size  of  the  table,
 2464%   placing a cell with  class  =skip=,   indicating  the  number of
 2465%   skipped rows.
 2466%
 2467%   Note that we can also achieve  alternate colouring using the CSS
 2468%   pseudo classes =|tr:nth-child(odd)|= and =|tr:nth-child(even)|=.
 2469
 2470table_rows(Goal, Rows) -->
 2471    table_rows(Rows, Goal, 1, -1).
 2472
 2473table_rows_top_bottom(Goal, Rows, inf, inf) -->
 2474    !,
 2475    table_rows(Rows, Goal, 1, -1).
 2476table_rows_top_bottom(Goal, Rows, MaxTop, MaxBottom) -->
 2477    { length(Rows, Count) },
 2478    (   { MaxTop+MaxBottom >= Count }
 2479    ->  table_rows(Rows, Goal, 1, -1)
 2480    ;   { Skip is Count-MaxBottom,
 2481          delete_list_prefix(Skip, Rows, BottomRows),
 2482          Skipped is Count-(MaxTop+MaxBottom)
 2483        },
 2484        table_rows(Rows, Goal, 1, MaxTop),
 2485        html(tr(class(skip),
 2486                [ th(colspan(10), 'Skipped ~D rows'-[Skipped])
 2487                ])),
 2488        table_rows(BottomRows, Goal, 1, -1)
 2489    ).
 2490
 2491table_rows(_, _, _, 0) --> !, [].
 2492table_rows([], _, _, _) --> [].
 2493table_rows([H|T], Goal, N, Left) -->
 2494    { N2 is N + 1,
 2495      (   N mod 2 =:= 0
 2496      ->  Class = even
 2497      ;   Class = odd
 2498      ),
 2499      Left2 is Left - 1
 2500    },
 2501    html(tr(class(Class), \call(Goal, H))),
 2502    table_rows(T, Goal, N2, Left2).
 2503
 2504delete_list_prefix(0, List, List) :- !.
 2505delete_list_prefix(_, [], []) :- !.
 2506delete_list_prefix(N, [_|T], List) :-
 2507    N2 is N - 1,
 2508    delete_list_prefix(N2, T, List).
 2509
 2510%!  list_prefixes(+Request)
 2511%
 2512%   List known RDF prefixes in various formats
 2513
 2514list_prefixes(Request) :-
 2515    Formats = [html,turtle],
 2516    http_parameters(Request,
 2517                    [ format(Format,
 2518                             [ oneof(Formats),
 2519                               description('Output format'),
 2520                               default(html)
 2521                             ])
 2522                    ]),
 2523    findall(Prefix-URI,
 2524            rdf_current_ns(Prefix, URI),
 2525            Pairs),
 2526    keysort(Pairs, Sorted),
 2527    prefix_actions(Options),
 2528    reply_html_page(cliopatria(default),
 2529                    title('RDF prefixes (namespaces)'),
 2530                    [ h1('Known RDF prefixes (namespaces)'),
 2531                      \explain_prefixes,
 2532                      \prefix_table(Format, Sorted, Options),
 2533                      \prefix_formats(Formats, Format, Request)
 2534                    ]).
 2535
 2536prefix_actions([edit(true)]) :-
 2537    logged_on(User),
 2538    !,
 2539    catch(check_permission(User, write(_, del_prefix(_))), _, fail),
 2540    !.
 2541prefix_actions([]).
 2542
 2543explain_prefixes -->
 2544    html(p([ 'The following prefixes are known and may be used \c
 2545                  without declaration in SPARQL queries to this server.'
 2546           ])).
 2547
 2548prefix_formats(Formats, Format, Request) -->
 2549    { select(Format, Formats, Alt)
 2550    },
 2551    html(p(class('prefix-format'),
 2552           [ 'Also available in ',
 2553             \alt_formats(Alt, Request)
 2554           ])).
 2555
 2556alt_formats([], _) --> [].
 2557alt_formats([H|T], Request) -->
 2558    { http_reload_with_parameters(Request, [format(H)], HREF)
 2559    },
 2560    html(a(href(HREF), H)),
 2561    (   {T==[]}
 2562    ->  []
 2563    ;   html(' and '),
 2564        alt_formats(T, Request)
 2565    ).
 2566
 2567prefix_table(html, Pairs, Options) -->
 2568    html(table(class(block),
 2569               [ \prefix_table_header,
 2570                 \table_rows(prefix_row(Options), Pairs)
 2571               ])).
 2572prefix_table(turtle, Pairs, _) -->
 2573    html(pre(class(code),
 2574             \turtle_prefixes(Pairs))).
 2575
 2576prefix_table_header -->
 2577    html(tr([ th('Prefix'),
 2578              th('URI')
 2579            ])).
 2580
 2581prefix_row(Options, Prefix-URI) -->
 2582    { option(edit(true), Options),
 2583      !,
 2584      http_link_to_id(del_prefix, [prefix(Prefix)], HREF)
 2585    },
 2586    html([ td(Prefix),
 2587           td(URI),
 2588           td(a([ href(HREF),
 2589                  class('delete'),
 2590                  title('Remove prefix')
 2591                ], '\u232B'))
 2592         ]).
 2593prefix_row(_Options, Prefix-URI) -->
 2594    html([ td(Prefix),
 2595           td(URI)
 2596         ]).
 2597
 2598turtle_prefixes(Pairs) -->
 2599    { longest_prefix(Pairs, 0, Length),
 2600      PrefixCol is Length+10
 2601    },
 2602    turtle_prefixes(Pairs, PrefixCol).
 2603
 2604longest_prefix([], L, L).
 2605longest_prefix([Prefix-_|T], L0, L) :-
 2606    atom_length(Prefix, L1),
 2607    L2 is max(L0, L1),
 2608    longest_prefix(T, L2, L).
 2609
 2610turtle_prefixes([], _) --> [].
 2611turtle_prefixes([Prefix-URI|T], Col) -->
 2612    html('@prefix ~t~w: ~*|<~w> .~n'-[Prefix, Col, URI]),
 2613    turtle_prefixes(T, Col)