new from SWI

LGPL/debug.pl

@@ -1,11 +1,10 @@
-/*  $Id: debug.pl,v 1.1 2008-02-12 17:03:53 vsc Exp $
+/*  Part of SWI-Prolog
-
-    Part of SWI-Prolog
 
     Author:        Jan Wielemaker
-    E-mail:        jan@swi.psy.uva.nl
+    E-mail:        J.Wielemaker@vu.nl
     WWW:           http://www.swi-prolog.org
-    Copyright (C): 1985-2002, University of Amsterdam
+    Copyright (C): 1985-2012, University of Amsterdam
+			      VU University Amsterdam
 
     This program is free software; you can redistribute it and/or
     modify it under the terms of the GNU General Public License
@@ -19,7 +18,7 @@
 
     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
+    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 
     As a special exception, if you link this library with other files,
     compiled with a Free Software compiler, to produce an executable, this
@@ -30,19 +29,29 @@
 */
 
 :- module(prolog_debug,
-	  [ debug/3,			% +Topic, +Format, +Args
+	  [ debug/3,			% +Topic, +Format, :Args
 	    debug/1,			% +Topic
 	    nodebug/1,			% +Topic
 	    debugging/1,		% ?Topic
 	    debugging/2,		% ?Topic, ?Bool
 	    list_debug_topics/0,
+	    debug_message_context/1,	% (+|-)What
 
 	    assertion/1			% :Goal
 	  ]).
-
+:- use_module(library(error)).
-:- meta_predicate(assertion(:)).
+:- use_module(library(lists)).
 :- set_prolog_flag(generate_debug_info, false).
 
+:- meta_predicate
+	assertion(0),
+	debug(+,+,:).
+
+:- multifile prolog:assertion_failed/2.
+:- dynamic   prolog:assertion_failed/2.
+
+/*:- use_module(library(prolog_stack)).*/ % We use the autoloader if needed
+
 :- if(current_prolog_flag(dialect, yap)).
 
 :- use_module(library(hacks), [stack_dump/1]).
@@ -53,10 +62,15 @@ backtrace(N) :-
 
 :- endif.
 
-:- dynamic
+%:- set_prolog_flag(generate_debug_info, false).
-	debugging/2.
 
-/** <module> Print debug messages
+:- dynamic
+	debugging/3,			% Topic, Enabled, To
+	debug_context/1.
+
+debug_context(thread).
+
+/** <module> Print debug messages and test assertions
 
 This library is a replacement for  format/3 for printing debug messages.
 Messages are assigned a _topic_. By   dynamically  enabling or disabling
@@ -64,7 +78,7 @@ 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.
+graphical monitoring tool.
 
 ==
 ?- prolog_ide(debug_monitor).
@@ -80,11 +94,26 @@ program explicit, trapping the debugger if the condition does not hold.
 %%	debugging(-Topic) is nondet.
 %%	debugging(?Topic, ?Bool) is nondet.
 %
-%	Check whether we are debugging Topic or enumerate the topics we
+%	Examine debug topics. The form debugging(+Topic)  may be used to
-%	are debugging.
+%	perform more complex debugging tasks.   A typical usage skeleton
+%	is:
+%
+%	  ==
+%		(   debugging(mytopic)
+%		->  <perform debugging actions>
+%		;   true
+%		),
+%		...
+%	  ==
+%
+%	The other two calls are intended to examine existing and enabled
+%	debugging tokens and are typically not used in user programs.
 
 debugging(Topic) :-
-	debugging(Topic, true).
+	debugging(Topic, true, _To).
+
+debugging(Topic, Bool) :-
+	debugging(Topic, Bool, _To).
 
 %%	debug(+Topic) is det.
 %%	nodebug(+Topic) is det.
@@ -92,27 +121,51 @@ debugging(Topic) :-
 %	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.
+%	the start of a (load-)file without warnings.
+%
+%	For debug/1, Topic can be  a  term   Topic  >  Out, where Out is
+%	either a stream or  stream-alias  or   a  filename  (atom). This
+%	redirects debug information on this topic to the given output.
 
 debug(Topic) :-
 	debug(Topic, true).
 nodebug(Topic) :-
 	debug(Topic, false).
 
-debug(Topic, Val) :-
+debug(Spec, Val) :-
-	(   (   retract(debugging(Topic, _))
+	debug_target(Spec, Topic, Out),
-	    *-> assert(debugging(Topic, Val)),
+	(   (   retract(debugging(Topic, Enabled0, To0))
+	    *-> update_debug(Enabled0, To0, Val, Out, Enabled, To),
+		assert(debugging(Topic, Enabled, To)),
 		fail
 	    ;   (   prolog_load_context(file, _)
 		->  true
 		;   print_message(warning, debug_no_topic(Topic))
 		),
-	        assert(debugging(Topic, Val))
+		update_debug(false, [], Val, Out, Enabled, To),
+	        assert(debugging(Topic, Enabled, To))
 	    )
 	->  true
 	;   true
 	).
 
+debug_target(Spec, Topic, To) :-
+	nonvar(Spec),
+	Spec = (Topic > To), !.
+debug_target(Topic, Topic, -).
+
+update_debug(_, To0, true, -, true, To) :- !,
+	ensure_output(To0, To).
+update_debug(true, To0, true, Out, true, Output) :- !,
+	append(To0, [Out], Output).
+update_debug(false, _, true, Out, true, [Out]) :- !.
+update_debug(_, _, false, -, false, []) :- !.
+update_debug(true, [Out], false, Out, false, []) :- !.
+update_debug(true, To0, false, Out, true, Output) :- !,
+	delete(To0, Out, Output).
+
+ensure_output([], [user_error]) :- !.
+ensure_output(List, List).
 
 %%	debug_topic(+Topic) is det.
 %
@@ -120,10 +173,10 @@ debug(Topic, Val) :-
 %	topics available for debugging.
 
 debug_topic(Topic) :-
-	(   debugging(Registered, _),
+	(   debugging(Registered, _, _),
 	    Registered =@= Topic
 	->  true
-	;   assert(debugging(Topic, false))
+	;   assert(debugging(Topic, false, []))
 	).
 
 %%	list_debug_topics is det.
@@ -131,33 +184,97 @@ debug_topic(Topic) :-
 %	List currently known debug topics and their setting.
 
 list_debug_topics :-
-	format(user_error, '~*t~40|~n', "-"),
+	format(user_error, '~*t~45|~n', "-"),
-	format(user_error, '~w~t~30| ~w~n', ['Debug Topic', 'Activated']),
+	format(user_error, '~w~t ~w~35| ~w~n',
-	format(user_error, '~*t~40|~n', "-"),
+	       ['Debug Topic', 'Activated', 'To']),
-	(   debugging(Topic, Value),
+	format(user_error, '~*t~45|~n', "-"),
-	    format(user_error, '~w~t~30| ~w~n', [Topic, Value]),
+	(   debugging(Topic, Value, To),
+	    format(user_error, '~w~t ~w~35| ~w~n', [Topic, Value, To]),
 	    fail
 	;   true
 	).
 
-%%	debug(+Topic, +Format, +Args) is det.
+%%	debug_message_context(+What) is det.
 %
-%	As format/3 to user_error, but only does something if Topic
+%	Specify additional context for debug messages.   What  is one of
-%	is activated through debug/1.
+%	+Context or -Context, and Context is  one of =thread=, =time= or
+%	time(Format),  where  Format  is    a  format specification  for
+%	format_time/3 (default is =|%T.%3f|=).  Initially, debug/3 shows
+%	only thread information.
+
+debug_message_context(+Topic) :- !,
+	valid_topic(Topic, Del, Add),
+	retractall(debug_context(Del)),
+	assert(debug_context(Add)).
+debug_message_context(-Topic) :- !,
+	valid_topic(Topic, Del, _),
+	retractall(debug_context(Del)).
+debug_message_context(Term) :-
+	type_error(debug_message_context, Term).
+
+valid_topic(thread, thread, thread) :- !.
+valid_topic(time, time(_), time('%T.%3f')) :- !.
+valid_topic(time(Format), time(_), time(Format)) :- !.
+valid_topic(X, _, _) :-
+	domain_error(debug_message_context, X).
+
+
+%%	debug(+Topic, +Format, :Args) is det.
+%
+%	Format a message if debug topic  is enabled. Similar to format/3
+%	to =user_error=, but only prints if   Topic is activated through
+%	debug/1. Args is a  meta-argument  to   deal  with  goal for the
+%	@-command.   Output   is   first    handed     to    the    hook
+%	prolog:debug_print_hook/3.  If  this  fails,    Format+Args   is
+%	translated  to  text   using    the   message-translation   (see
+%	print_message/2) for the  term  debug(Format,   Args)  and  then
+%	printed to every matching destination   (controlled  by debug/1)
+%	using print_message_lines/3.
+%
+%	The message is preceded by '% ' and terminated with a newline.
+%
+%	@see	format/3.
 
 debug(Topic, Format, Args) :-
-	debugging(Topic, true), !,
+	debugging(Topic, true, To), !,
-	print_debug(Topic, Format, Args).
+	print_debug(Topic, To, Format, Args).
 debug(_, _, _).
 
 
+%%	prolog:debug_print_hook(+Topic, +Format, +Args) is semidet.
+%
+%	Hook called by debug/3.  This  hook   is  used  by the graphical
+%	frontend that can be activated using prolog_ide/1:
+%
+%	  ==
+%	  ?- prolog_ide(debug_monitor).
+%	  ==
+
 :- multifile
 	prolog:debug_print_hook/3.
 
-print_debug(Topic, Format, Args) :-
+print_debug(Topic, _To, Format, Args) :-
 	prolog:debug_print_hook(Topic, Format, Args), !.
-print_debug(_, Format, Args) :-
+print_debug(_, [], _, _) :- !.
-	print_message(informational, debug(Format, Args)).
+print_debug(Topic, To, Format, Args) :-
+	phrase('$messages':translate_message(debug(Format, Args)), Lines),
+	(   member(T, To),
+	    debug_output(T, Stream),
+	    print_message_lines(Stream, kind(debug(Topic)), Lines),
+	    fail
+	;   true
+	).
+
+
+debug_output(user, user_error) :- !.
+debug_output(Stream, Stream) :-
+	is_stream(Stream), !.
+debug_output(File, Stream) :-
+	open(File, append, Stream,
+	     [ close_on_abort(false),
+	       alias(File),
+	       buffer(line)
+	     ]).
 
 
 		 /*******************************
@@ -166,17 +283,36 @@ print_debug(_, Format, Args) :-
 
 %%	assertion(:Goal) is det.
 %
-%	Acts similar to C assert() macro.  It has no effect of Goal
+%	Acts similar to C assert()  macro.  It   has  no  effect if Goal
-%	succeeds.  If Goal fails it prints a message, a stack-trace
+%	succeeds. If Goal fails or throws    an exception, the following
-%	and finally traps the debugger.
+%	steps are taken:
+%
+%	  * call prolog:assertion_failed/2.  If prolog:assertion_failed/2
+%	    fails, then:
+%
+%	    - If this is an interactive toplevel thread, print a
+%	      message, the stack-trace, and finally trap the debugger.
+%	    - Otherwise, throw error(assertion_error(Reason, G),_) where
+%	      Reason is one of =fail= or the exception raised.
 
 assertion(G) :-
-	\+ \+ G, !.			% avoid binding variables
+	\+ \+ catch(G,
+		    Error,
+		    assertion_failed(Error, G)),
+	!.
 assertion(G) :-
-	print_message(error, assumption_failed(G)),
+	assertion_failed(fail, G),
+	assertion_failed.		% prevent last call optimization.
+
+assertion_failed(Reason, G) :-
+	prolog:assertion_failed(Reason, G), !.
+assertion_failed(Reason, G) :-
+	print_message(error, assertion_failed(Reason, G)),
 	backtrace(10),
-	trace,
+	(   current_prolog_flag(break_level, _)	% interactive thread
-	assertion_failed.
+	->  trace
+	;   throw(error(assertion_error(Reason, G), _))
+	).
 
 assertion_failed.
 
@@ -193,34 +329,28 @@ assertion_failed.
 		 *******************************/
 
 :- multifile
-	user:goal_expansion/2.
+	system:goal_expansion/2.
 
-user:goal_expansion(debug(Topic,_,_), true) :-
+system:goal_expansion(debug(Topic,_,_), true) :-
 	(   current_prolog_flag(optimise, true)
 	->  true
 	;   debug_topic(Topic),
 	    fail
 	).
-user:goal_expansion(debugging(Topic), fail) :-
+system:goal_expansion(debugging(Topic), fail) :-
 	(   current_prolog_flag(optimise, true)
 	->  true
 	;   debug_topic(Topic),
 	    fail
 	).
-user:goal_expansion(assertion(G), Goal) :-
+system:goal_expansion(assertion(_), Goal) :-
-	(   current_prolog_flag(optimise, true)
+	current_prolog_flag(optimise, true),
-	->  Goal = true
+	Goal = true.
-	;   expand_goal(G, G2),
+system:goal_expansion(assume(_), Goal) :-
-	    Goal = assertion(G2)
-	).
-user:goal_expansion(assume(G), Goal) :-
 	print_message(informational,
 		      compatibility(renamed(assume/1, assertion/1))),
-	(   current_prolog_flag(optimise, true)
+	current_prolog_flag(optimise, true),
-	->  Goal = true
+	Goal = true.
-	;   expand_goal(G, G2),
-	    Goal = assertion(G2)
-	).
 
 
 		 /*******************************
@@ -230,13 +360,41 @@ user:goal_expansion(assume(G), Goal) :-
 :- multifile
 	prolog:message/3.
 
-prolog:message(assumption_failed(G)) -->
+prolog:message(assertion_failed(_, G)) -->
-	[ 'Assertion failed: ~p'-[G] ].
+	[ 'Assertion failed: ~q'-[G] ].
 prolog:message(debug(Fmt, Args)) -->
-	{ thread_self(Me) },
+	show_thread_context,
-	(   { Me == main }
+	show_time_context,
-	->  [ Fmt-Args ]
+	[ Fmt-Args ].
-	;   [ '[Thread ~w] '-[Me], Fmt-Args ]
-	).
 prolog:message(debug_no_topic(Topic)) -->
 	[ '~q: no matching debug topic (yet)'-[Topic] ].
+
+show_thread_context -->
+	{ debug_context(thread),
+	  thread_self(Me) ,
+	  Me \== main
+	},
+	[ '[Thread ~w] '-[Me] ].
+show_thread_context -->
+	[].
+
+show_time_context -->
+	{ debug_context(time(Format)),
+	  get_time(Now),
+	  format_time(string(S), Format, Now)
+	},
+	[ '[~w] '-[S] ].
+show_time_context -->
+	[].
+
+		 /*******************************
+		 *	       HOOKS		*
+		 *******************************/
+
+%%	prolog:assertion_failed(+Reason, +Goal) is semidet.
+%
+%	This hook is called if the Goal  of assertion/1 fails. Reason is
+%	unified with either =fail= if Goal simply failed or an exception
+%	call otherwise. If this hook  fails,   the  default behaviour is
+%	activated.  If  the  hooks  throws  an   exception  it  will  be
+%	propagated into the caller of assertion/1.