1/*  Part of SWI-Prolog
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@cs.vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (C): 2014-2015, VU University Amsterdam
    7
    8    This program is free software; you can redistribute it and/or
    9    modify it under the terms of the GNU General Public License
   10    as published by the Free Software Foundation; either version 2
   11    of the License, or (at your option) any later version.
   12
   13    This program is distributed in the hope that it will be useful,
   14    but WITHOUT ANY WARRANTY; without even the implied warranty of
   15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   16    GNU General Public License for more details.
   17
   18    You should have received a copy of the GNU General Public
   19    License along with this library; if not, write to the Free Software
   20    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   21
   22    As a special exception, if you link this library with other files,
   23    compiled with a Free Software compiler, to produce an executable, this
   24    library does not by itself cause the resulting executable to be covered
   25    by the GNU General Public License. This exception does not however
   26    invalidate any other reasons why the executable file might be covered by
   27    the GNU General Public License.
   28*/
   29
   30:- module(swish_render_prolog,
   31	  [ term_rendering//3			% +Term, +Vars, +Options
   32	  ,clauses//1
   33	  ]).   34:- use_module(library(apply)).   35:- use_module(library(lists)).   36:- use_module(library(option)).   37:- use_module(library(http/html_write)).   38:- use_module(library(http/term_html)).   39:- use_module(library(slipcover)).   40:- use_module('../render').   41
   42:- register_renderer(prolog, "Render a logic program").   43
   44/** <module> SWISH table renderer
   45
   46Render table-like data.
   47*/
   48
   49%%	term_rendering(+Term, +Vars, +Options)//
   50%
   51%	Renders Term as  a  table.   This  renderer  recognises  several
   52%	representations of table-like data:
   53%
   54%	  $ A list of terms of equal arity :
   55%	  $ A list of lists of equal length :
   56%
   57%	@tbd: recognise more formats
   58
   59term_rendering(Term, _Vars, _Options) -->
   60	{is_list_of_clauses(Term)
   61	}, !,
   62	html(pre(\clauses(Term))).
   63
   64clauses([]) --> [].
   65clauses([H1|T]) -->
   66	{
   67         copy_term(H1,HC),
   68	 numbervars(HC,0,_),
   69         (HC=(H:-B)->
   70	   list2and(BL,B)
   71         ;
   72           BL=[],
   73           H=HC
   74         )
   75	},
   76	single_clause(H,BL),
   77	clauses(T).
   78
   79single_clause(H,B)-->
   80  {format(atom(I),' :-~n',[])},
   81  head(H,B,I).
   82
   83head(H,[],_I)-->
   84  {format(atom(A),"~q.~n~n",[H])},!,
   85  [A].
   86 
   87head(H,B,I)-->
   88  {format(atom(A),"~q",[H])},!,
   89  [A,I],
   90  body(B).
   91
   92
   93body([])-->
   94  {format(atom(A),"  true.~n~n",[])},
   95  [A].
   96
   97body([H])-->
   98  {format(atom(A),"  ~q.~n~n",[H])},!,
   99  [A].
  100
  101body([H|T])-->
  102  {format(atom(A),"  ~q,~n",[H])},
  103  [A],body(T).
  104
  105
  106
  107
  108
  109
  110%%	is_list_of_terms(@Term, -Rows, -Cols) is semidet.
  111%
  112%	Recognises a list of terms with   the  same functor and non-zero
  113%	ariry.
  114
  115is_list_of_clauses(Term) :-
  116	is_list(Term), Term \== []