This file is indexed.

/usr/share/Yap/debug.pl is in yap 5.1.3-6.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
/*  $Id: debug.pl,v 1.1 2008/02/12 17:03:53 vsc Exp $

    Part of SWI-Prolog

    Author:        Jan Wielemaker
    E-mail:        jan@swi.psy.uva.nl
    WWW:           http://www.swi-prolog.org
    Copyright (C): 1985-2002, University of Amsterdam

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License
    as published by the Free Software Foundation; either version 2
    of the License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    As a special exception, if you link this library with other files,
    compiled with a Free Software compiler, to produce an executable, this
    library does not by itself cause the resulting executable to be covered
    by the GNU General Public License. This exception does not however
    invalidate any other reasons why the executable file might be covered by
    the GNU General Public License.
*/

:- module(prolog_debug,
	  [ debug/3,			% +Topic, +Format, +Args
	    debug/1,			% +Topic
	    nodebug/1,			% +Topic
	    debugging/1,		% ?Topic
	    debugging/2,		% ?Topic, ?Bool
	    list_debug_topics/0,

	    assertion/1			% :Goal
	  ]).

:- meta_predicate(assertion(:)).
:- set_prolog_flag(generate_debug_info, false).

:- if(current_prolog_flag(dialect, yap)).

:- use_module(library(hacks), [stack_dump/1]).

% this is as good as I can do. 
backtrace(N) :-
	stack_dump(N).

:- endif.

:- dynamic
	debugging/2.

/** <module> Print debug messages

This library is a replacement for  format/3 for printing debug messages.
Messages are assigned a _topic_. By   dynamically  enabling or disabling
topics the user can  select  desired   messages.  Debug  statements  are
removed when the code is compiled for optimization.

See manual for details. With XPCE, you can use the call below to start a
graphical monitorring tool.

==
?- prolog_ide(debug_monitor).
==

Using the predicate assertion/1 you  can   make  assumptions  about your
program explicit, trapping the debugger if the condition does not hold.

@author	Jan Wielemaker
*/

%%	debugging(+Topic) is semidet.
%%	debugging(-Topic) is nondet.
%%	debugging(?Topic, ?Bool) is nondet.
%
%	Check whether we are debugging Topic or enumerate the topics we
%	are debugging.

debugging(Topic) :-
	debugging(Topic, true).

%%	debug(+Topic) is det.
%%	nodebug(+Topic) is det.
%
%	Add/remove a topic from being   printed.  nodebug(_) removes all
%	topics. Gives a warning if the topic is not defined unless it is
%	used from a directive. The latter allows placing debug topics at
%	the start a a (load-)file without warnings.

debug(Topic) :-
	debug(Topic, true).
nodebug(Topic) :-
	debug(Topic, false).

debug(Topic, Val) :-
	(   (   retract(debugging(Topic, _))
	    *-> assert(debugging(Topic, Val)),
		fail
	    ;   (   prolog_load_context(file, _)
		->  true
		;   print_message(warning, debug_no_topic(Topic))
		),
	        assert(debugging(Topic, Val))
	    )
	->  true
	;   true
	).


%%	debug_topic(+Topic) is det.
%
%	Declare a topic for debugging.  This can be used to find all
%	topics available for debugging.

debug_topic(Topic) :-
	(   debugging(Registered, _),
	    Registered =@= Topic
	->  true
	;   assert(debugging(Topic, false))
	).

%%	list_debug_topics is det.
%	
%	List currently known debug topics and their setting.

list_debug_topics :-
	format(user_error, '~*t~40|~n', "-"),
	format(user_error, '~w~t~30| ~w~n', ['Debug Topic', 'Activated']),
	format(user_error, '~*t~40|~n', "-"),
	(   debugging(Topic, Value),
	    format(user_error, '~w~t~30| ~w~n', [Topic, Value]),
	    fail
	;   true
	).

%%	debug(+Topic, +Format, +Args) is det.
%
%	As format/3 to user_error, but only does something if Topic
%	is activated through debug/1.

debug(Topic, Format, Args) :-
	debugging(Topic, true), !,
	print_debug(Topic, Format, Args).
debug(_, _, _).


:- multifile
	prolog:debug_print_hook/3.

print_debug(Topic, Format, Args) :-
	prolog:debug_print_hook(Topic, Format, Args), !.
print_debug(_, Format, Args) :-
	print_message(informational, debug(Format, Args)).


		 /*******************************
		 *	     ASSERTION		*
		 *******************************/

%%	assertion(:Goal) is det.
%	
%	Acts similar to C assert() macro.  It has no effect of Goal
%	succeeds.  If Goal fails it prints a message, a stack-trace
%	and finally traps the debugger.

assertion(G) :-
	\+ \+ G, !.			% avoid binding variables
assertion(G) :-
	print_message(error, assumption_failed(G)),
	backtrace(10),
	trace,
	assertion_failed.

assertion_failed.

%%	assume(:Goal) is det.
%	
%	Acts similar to C assert() macro.  It has no effect of Goal
%	succeeds.  If Goal fails it prints a message, a stack-trace
%	and finally traps the debugger.
%	
%	@deprecated	Use assertion/1 in new code.

		 /*******************************
		 *	     EXPANSION		*
		 *******************************/

:- multifile
	user:goal_expansion/2.

user:goal_expansion(debug(Topic,_,_), true) :-
	(   current_prolog_flag(optimise, true)
	->  true
	;   debug_topic(Topic),
	    fail
	).
user:goal_expansion(debugging(Topic), fail) :-
	(   current_prolog_flag(optimise, true)
	->  true
	;   debug_topic(Topic),
	    fail
	).
user:goal_expansion(assertion(G), Goal) :-
	(   current_prolog_flag(optimise, true)
	->  Goal = true
	;   expand_goal(G, G2),
	    Goal = assertion(G2)
	).
user:goal_expansion(assume(G), Goal) :-
	print_message(informational,
		      compatibility(renamed(assume/1, assertion/1))),
	(   current_prolog_flag(optimise, true)
	->  Goal = true
	;   expand_goal(G, G2),
	    Goal = assertion(G2)
	).


		 /*******************************
		 *	      MESSAGES		*
		 *******************************/

:- multifile
	prolog:message/3.

prolog:message(assumption_failed(G)) -->
	[ 'Assertion failed: ~p'-[G] ].
prolog:message(debug(Fmt, Args)) -->
	{ thread_self(Me) },
	(   { Me == main }
	->  [ Fmt-Args ]
	;   [ '[Thread ~w] '-[Me], Fmt-Args ]
	).
prolog:message(debug_no_topic(Topic)) -->
	[ '~q: no matching debug topic (yet)'-[Topic] ].