1/*  Part of SWI-Prolog
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (c)  2006-2013, University of Amsterdam
    7                              VU University 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(pldoc_register,
   37          [ process_stored_comments/0
   38          ]).   39:- use_module(doc_process).   40:- use_module(library(pldoc)).   41:- set_prolog_flag(generate_debug_info, false).   42
   43pldoc_module(pldoc_modes).              % avoid recursive behaviour
   44pldoc_module(pldoc_process).
   45pldoc_module(pldoc_wiki).
   46pldoc_module(pldoc).
   47pldoc_module(lists).
   48pldoc_module(apply).
   49pldoc_module(pairs).
   50
   51                 /*******************************
   52                 *            REGISTER          *
   53                 *******************************/
   54
   55:- multifile
   56    prolog:comment_hook/3,
   57    user:message_hook/3.   58
   59:- dynamic
   60    mydoc/3.                        %  +Comments, +TermPos, +File
   61
   62do_comment_hook(_, _, _, _) :-
   63    current_prolog_flag(pldoc_collecting, false),
   64    !.
   65do_comment_hook(Comments, TermPos, File, _) :-
   66    pldoc_loading,
   67    !,
   68    assert(mydoc(Comments, TermPos, File)).
   69do_comment_hook(Comments, TermPos, File, _Term) :-
   70    prolog_load_context(module, Module),
   71    pldoc_module(Module),
   72    !,
   73    assert(mydoc(Comments, TermPos, File)).
   74do_comment_hook(Comments, TermPos, File, _) :-
   75    process_comments(Comments, TermPos, File).
   76
   77user:message_hook(load_file(done(0, _F, _A, _M, _T, _H)), _, _) :-
   78    (   mydoc(_, _, _)
   79    ->  debug(pldoc, 'Processing delayed comments', []),
   80        process_stored_comments
   81    ),
   82    fail.

 prolog:comment_hook(+Comments, +TermPos, +Term) is det

Hook called by the compiler and cross-referencer. In addition to the comment, it passes the term itself to see what term is commented as well as the start-position of the term to distinguish between comments before the term and inside it.

Arguments:

Comments	- List of comments read before the end of Term
TermPos	- Start location of Term
Term	- Actual term read

   95prolog:comment_hook(Comments, TermPos, Term) :-
   96    source_location(File, _TermLine),
   97    setup_call_cleanup(
   98        '$push_input_context'(pldoc),  % Preserve input file and line
   99        do_comment_hook(Comments, TermPos, File, Term),
  100        '$pop_input_context').
  101
  102process_stored_comments :-
  103    forall(retract(mydoc(Comments, TermPos, File)),
  104           delayed_process(Comments, TermPos, File)).
  105
  106delayed_process(Comments, TermPos, File) :-
  107    module_property(Module, file(File)),
  108    setup_call_cleanup(
  109        '$set_source_module'(Old, Module),
  110        process_comments(Comments, TermPos, File),
  111        '$set_source_module'(_, Old))