1/*  Part of XPCE --- The SWI-Prolog GUI toolkit
   2
   3    Author:        Jan Wielemaker and Anjo Anjewierden
   4    E-mail:        jan@swi.psy.uva.nl
   5    WWW:           http://www.swi.psy.uva.nl/projects/xpce/
   6    Copyright (c)  1985-2002, University of Amsterdam
   7    All rights reserved.
   8
   9    Redistribution and use in source and binary forms, with or without
  10    modification, are permitted provided that the following conditions
  11    are met:
  12
  13    1. Redistributions of source code must retain the above copyright
  14       notice, this list of conditions and the following disclaimer.
  15
  16    2. Redistributions in binary form must reproduce the above copyright
  17       notice, this list of conditions and the following disclaimer in
  18       the documentation and/or other materials provided with the
  19       distribution.
  20
  21    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  25    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  29    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  31    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  32    POSSIBILITY OF SUCH DAMAGE.
  33*/
  34
  35:- module(pce_help_file,
  36          [ pce_help_file/2,
  37            pce_help/2
  38          ]).
  39:- use_module(library(pce)).
  40:- require([ atomic_list_concat/2
  41           , is_absolute_file_name/1
  42           ]).
  43
  44:- multifile
  45    user:file_search_path/2.
  46:- dynamic
  47    user:file_search_path/2.
  48
  49user:file_search_path(pce_help, pce('appl-help')).
  50
  51:- pce_autoload(helper, library(pce_helper)).
  52:- pce_global(@helper, new(helper)).
  53
  54:- dynamic
  55    resource/3.
  56
  57/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  58This module is closely  connected  to   library(pce_helper).   It  is  a
  59separate module to allow the execution of the directive pce_help_file/2,
  60to register a new help database without   forcing the entire help system
  61to be loaded.
  62
  63Loading this module (normally through the   autoloader  or the require/1
  64directive)  will  make  the  necessary    pce_global   and  pce_autoload
  65declarations to load the help-system itself as soon as it is referenced.
  66- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
  67
  68%!  pce_help_file(+DataBaseId, +FileName).
  69%
  70%   Declare `FileName' to hold a helper-format file holding the
  71%   help-database `DataBaseId'.  FileName will be converted into
  72%   an absolute filename.  Normally used as a directive.
  73
  74pce_help_file(Id, FileName) :-
  75    (   atom(FileName),
  76        \+ is_absolute_file_name(FileName)
  77    ->  prolog_load_context(directory, Cwd),
  78        atomic_list_concat([Cwd, /, FileName], Path)
  79    ;   Path = FileName
  80    ),
  81    retractall(resource(Id, help, Path)),
  82    asserta(resource(Id, help, Path)).
  83
  84%!  pce_help(+DataBaseId, +Label)
  85%
  86%   Start @helper/helper on the help module `DataBaseId', searching
  87%   for a fragment with label `Label'.  Normally invoked through the
  88%   send directly.
  89
  90pce_help(DataBase, Label) :-
  91    send(@helper, give_help, DataBase, Label).