diff --git a/pl/attributes.yap b/pl/attributes.yap
index 1f5e0f213..b820c6856 100644
--- a/pl/attributes.yap
+++ b/pl/attributes.yap
@@ -324,7 +324,7 @@ do_continuation(Continuation, Module1) :-
 execute_continuation(Continuation, Module1) :-
 	'$undefined'(Continuation, Module1), !,
 	'$current_module'( M ),
-	'$swi_current_prolog_flag'( M:unknown, Default ),
+	current_prolog_flag( M:unknown, Default ),
         '$undefp'([Module1|Continuation] , Default ).
 execute_continuation(Continuation, Mod) :-
          % do not do meta-expansion nor any fancy stuff.
diff --git a/pl/boot.yap b/pl/boot.yap
index acbc7d889..9a684c185 100644
--- a/pl/boot.yap
+++ b/pl/boot.yap
@@ -308,14 +308,14 @@ true :- true.
     '$init_system'.
 
 '$do_live' :-
-    repeat,
-    '$current_module'(Module),
-    ( Module==user ->
-      '$compile_mode'(_,0)
-    ;
-      format(user_error,'[~w]~n', [Module])
-    ),
-    '$system_catch'('$enter_top_level',Module,Error,user:'$Error'(Error)).
+	repeat,
+	'$current_module'(Module),
+	( Module==user ->
+	  '$compile_mode'(_,0)
+	;
+	  format(user_error,'[~w]~n', [Module])
+	),
+	'$system_catch'('$enter_top_level',Module,Error,user:'$Error'(Error)).
 
 
 '$init_system' :-
@@ -324,20 +324,14 @@ true :- true.
     set_value('$yap_inited', true),
     % do catch as early as possible
     (
-     '$access_yap_flags'(15, 0),
-     '$access_yap_flags'(22, 0),
-     \+ '$uncaught_throw'
+     current_prolog_flag(halt_after_consult, false),
+     current_prolog_flag(verbose, normal),
+      \+ '$uncaught_throw'
     ->
      '$version'
     ;
      true
     ),
-    (
-     '$access_yap_flags'(22, 0) ->
-	'$swi_set_prolog_flag'(verbose,  normal)
-    ;
-	'$swi_set_prolog_flag'(verbose,  silent)
-    ),
 %	'$init_preds', % needs to be done before library_directory
 %	(
 %	 retractall(user:library_directory(_)),
@@ -347,17 +341,16 @@ true :- true.
 %	;
 %	 true
 %	),
-    '$swi_current_prolog_flag'(file_name_variables, OldF),
-    '$swi_set_prolog_flag'(file_name_variables, true),
+    current_prolog_flag(file_name_variables, OldF),
+    set_prolog_flag(file_name_variables, true),
     '$init_consult',
-    '$swi_set_prolog_flag'(file_name_variables, OldF),
-    '$init_win_graphics',
+    set_prolog_flag(file_name_variables, OldF),
     '$init_globals',
-    '$swi_set_prolog_flag'(fileerrors, true),
+    set_prolog_flag(fileerrors, true),
     set_value('$gc',on),
     ('$exit_undefp' -> true ; true),
     prompt1(' ?- '),
-    '$swi_set_prolog_flag'(debug, false),
+    set_prolog_flag(debug, false),
 	% simple trick to find out if this is we are booting from Prolog.
 	% boot from a saved state
 	(
@@ -369,7 +362,7 @@ true :- true.
 	 ->
 	  bootstrap(X),
 	  module( user ),
-	  qsave_program( "startup.yss")
+	  qsave_program( 'startup.yss')
 	 ;
 	  true
 	 )
@@ -385,7 +378,7 @@ true :- true.
 	'$run_at_thread_start'.
 
 '$init_globals' :-
-	% '$swi_set_prolog_flag'(break_level, 0),
+	% set_prolog_flag(break_level, 0),
 	% '$set_read_error_handler'(error), let the user do that
 	nb_setval('$chr_toplevel_show_store',false).
 
@@ -433,8 +426,9 @@ true :- true.
 
 /* main execution loop							*/
 '$read_toplevel'(Goal, Bindings) :-
+	fail,
 	'$pred_exists'(read_history(_,_,_,_,_,_), user),
-	'$swi_current_prolog_flag'(readline, true), !,
+	current_prolog_flag(readline, true), !,
 	read_history(h, '!h',
                          [trace, end_of_file],
                          Prompt, Goal, Bindings), !,
@@ -446,34 +440,24 @@ true :- true.
 '$read_toplevel'(Goal, Bindings) :-
 	prompt1('?- '),
 	prompt(_,'|: '),
-			(print_message(error, E),
-	                 '$handle_toplevel_error'(Line, E))),
-	(
-	    '$pred_exists'(rl_add_history(_), user)
-	->
-	    format(atom(CompleteLine), '~W~W',
-		   [ Line, [partial(true)],
-		     '.', [partial(true)]
-		   ]),
-	    user:rl_add_history(CompleteLine)
-	;
-	    true
-	),
-	'$system_catch'(
-			atom_to_term(Line, Goal, Bindings), prolog, E,
-			(   print_message(error, E),
-			    fail
-			)
-		       ), !.
+	'$system_catch'(read_term(user_input,
+				  Goal,
+				  [variable_names(Bindings)]),
+			prolog, E, '$handle_toplevel_error'( E) ).
 
-'$handle_toplevel_error'(_, syntax_error(_)) :-
+'$handle_toplevel_error'( syntax_error(_)) :-
 	!,
 	fail.
-'$handle_toplevel_error'(end_of_file, error(io_error(read,user_input),_)) :-
+'$handle_toplevel_error'( error(io_error(read,user_input),_)) :-
 	!.
 '$handle_toplevel_error'(_, E) :-
 	throw(E).
 
+
+/** @pred  stream_property( _Stream_, _Prop_) 
+
+*/
+
 % reset alarms when entering top-level.
 '$enter_top_level' :-
 	'$alarm'(0, 0, _, _),
@@ -482,8 +466,8 @@ true :- true.
 	'$clean_up_dead_clauses',
 	fail.
 '$enter_top_level' :-
-	'$swi_current_prolog_flag'(break_level, BreakLevel),
-        '$swi_current_prolog_flag'(debug, DBON),
+	current_prolog_flag(break_level, BreakLevel),
+        current_prolog_flag(debug, DBON),
 	(
 	 '$nb_getval'('$trace', on, fail)
 	->
@@ -501,7 +485,7 @@ true :- true.
 	get_value('$top_level_goal',GA), GA \= [], !,
 	set_value('$top_level_goal',[]),
 	'$run_atom_goal'(GA),
-	'$swi_current_prolog_flag'(break_level, BreakLevel),
+	current_prolog_flag(break_level, BreakLevel),
 	(
 	 Breaklevel \= 0
 	->
@@ -523,7 +507,7 @@ true :- true.
 	nb_setval('$debug_run',off),
 	nb_setval('$debug_jump',off),
 	'$command'(Command,Varnames,_Pos,top),
-	'$swi_current_prolog_flag'(break_level, BreakLevel),
+	current_prolog_flag(break_level, BreakLevel),
 	(
 	 BreakLevel \= 0
 	->
@@ -545,17 +529,13 @@ true :- true.
  '$erase_sets'.
 
 '$version' :-
-	get_value('$version_name',VersionName),
-	 print_message(help, version(VersionName)),
-	 get_value('$myddas_version_name',MYDDASVersionName),
-	 MYDDASVersionName \== [],
-	 print_message(help, myddas_version(MYDDASVersionName)),
-	 fail.
- '$version' :-
-	 recorded('$version',VersionName,_),
-	 print_message(help, VersionName),
-	 fail.
- '$version'.
+	current_prolog_flag(version_git,VersionGit),
+	current_prolog_flag(compiled_at,AT),
+	current_prolog_flag(version_data, yap(Mj, Mi,  Patch, _) ),
+	sub_atom( VersionGit, 0, 8, _, VERSIONGIT ),
+	format(user_error, '% YAP ~d.~d.~d-~a (compiled  ~a)~n', [Mj,Mi, Patch, VERSIONGIT,  AT]),
+	fail.
+'$version'.
 
 /** @pred  repeat is iso
 Succeeds repeatedly.
@@ -604,7 +584,7 @@ number of steps.
 	recorda('$result',going,_).
 
 '$command'(C,VL,Pos,Con) :-
-	'$access_yap_flags'(9,1), !,
+	current_prolog_flag(strict_iso, true), !,      /* strict_iso on */
 	 '$execute_command'(C,VL,Pos,Con,C).
 '$command'(C,VL,Pos,Con) :-
 	( (Con = top ; var(C) ; C = [_|_])  ->
@@ -675,7 +655,7 @@ number of steps.
  % YAP accepts everything everywhere
  %
  '$process_directive'(G, top, M, VL, Pos) :-
-	 '$access_yap_flags'(8, 0), !, % YAP mode, go in and do it,
+	 current_prolog_flag(language_mode, yap), !,      /* strict_iso on */
 	 '$process_directive'(G, consult, M, VL, Pos).
  '$process_directive'(G, top, _, _, _) :- !,
 	 '$do_error'(context_error((:- G),clause),query).
@@ -694,8 +674,8 @@ number of steps.
  %
  % ISO does not allow goals (use initialization).
  %
- '$process_directive'(D, _, M, VL, Pos) :-
-	 '$access_yap_flags'(8, 1), !, % ISO Prolog mode, go in and do it,
+'$process_directive'(D, _, M, VL, Pos) :-
+	current_prolog_flag(language_mode, iso), !, % ISO Prolog mode, go in and do it,
 	 '$do_error'(context_error((:- M:D),query),directive).
  %
  % but YAP and SICStus does.
@@ -718,7 +698,7 @@ number of steps.
 	 '$go_compile_clause'(G,V,Pos,5,Source),
 	 fail.
 '$continue_with_command'(consult,V,Pos,G,Source) :-
-     '$go_compile_clause'(G,V,Pos,13,Source),
+	'$go_compile_clause'(G,V,Pos,13,Source),
 	 fail.
 '$continue_with_command'(top,V,_,G,_) :-
 	 '$query'(G,V).
@@ -754,18 +734,16 @@ number of steps.
  % process an input clause
  '$$compile'(G, G0, L, Mod) :-
 	 '$head_and_body'(G,H,_),
-	 '$flags'(H, Mod, Fl, Fl),
-	 is(NFl, /\, Fl, 0x00002000),
 	 (
-	  NFl \= 0
+	  '$is_dynamic'(H, Mod)
 	 ->
-	  '$assertz_dynamic'(L,G,G0,Mod)
+	  '$assertz_dynamic'(L, G, G0, Mod)
 	 ;
 	  '$nb_getval'('$assert_all',on,fail)
 	 ->
 	  functor(H,N,A),
 	  '$dynamic'(N/A,Mod),
-	  '$assertz_dynamic'(L,G,G0,Mod)
+	  '$assertz_dynamic'(L, G, G0, Mod)
 	 ;
 	  '$not_imported'(H, Mod),
 	  '$compile'(G, L, G0, Mod)
@@ -897,7 +875,7 @@ number of steps.
         flush_output,
 	fail.
 '$present_answer'((?-), Answ) :-
-	'$swi_current_prolog_flag'(break_level, BL ),
+	current_prolog_flag(break_level, BL ),
 	( BL \= 0 -> 	format(user_error, '[~p] ',[BL]) ;
 			true ),
         ( recorded('$print_options','$toplevel'(Opts),_) ->
@@ -1139,7 +1117,7 @@ incore(G) :- '$execute'(G).
     ).
 
 '$enable_debugging' :-
-	'$swi_current_prolog_flag'(debug, false), !.
+	current_prolog_flag(debug, false), !.
 '$enable_debugging' :-
 	'$nb_getval'('$trace', on, fail), !,
 	'$creep'.
@@ -1334,12 +1312,12 @@ bootstrap(F) :-
 %	'$open'(F, '$csult', Stream, 0, 0, F),
 %	'$file_name'(Stream,File),
 	open(F, read, Stream),
-	stream_property(Stream, file_name(File)),
+	stream_property(Stream, [file_name(File)]),
 	'$start_consult'(consult, File, LC),
 	file_directory_name(File, Dir),
 	working_directory(OldD, Dir),
 	(
-	  '$swi_current_prolog_flag'(verbose_load, silent)
+	  current_prolog_flag(verbose_load, silent)
 	->
 	  true
 	;
@@ -1351,7 +1329,7 @@ bootstrap(F) :-
 	'$current_module'(_, prolog),
 	'$end_consult',
 	(
-	  '$swi_current_prolog_flag'(verbose_load, silent)
+	  current_prolog_flag(verbose_load, silent)
 	->
 	  true
 	;
@@ -1388,7 +1366,7 @@ bootstrap(F) :-
 	!.
 
 '$enter_command'(Stream,Mod,Status) :-
-	read_clause(Stream, Command, [variable_names(Vars), term_position(Pos), syntax_errors(dec10) ]),
+	read_term(Stream, Command, [variable_names(Vars), term_position(Pos), syntax_errors(dec10) ]),
 	'$command'(Command,Vars,Pos,Status).
 
 '$abort_loop'(Stream) :-
@@ -1426,7 +1404,7 @@ bootstrap(F) :-
 	'$module_expansion'(Term, Expanded0, ExpandedI, HeadMod, BodyMod, SourceMod), !,
 %format('      -> ~w~n',[Expanded0]),
 	(
-	 '$access_yap_flags'(9,1)      /* strict_iso on */
+	 current_prolog_flag(strict_iso, true)      /* strict_iso on */
         ->
 	 Expanded = ExpandedI,
 	 '$check_iso_strict_clause'(Expanded0)
@@ -1571,7 +1549,7 @@ catch_ball(Ball, V) :-
 catch_ball(C, C).
 
 '$run_toplevel_hooks' :-
-	'$swi_current_prolog_flag'(break_level, 0 ),
+	current_prolog_flag(break_level, 0 ),
 	recorded('$toplevel_hooks',H,_),
 	H \= fail, !,
 	( call(user:H1) -> true ; true).
diff --git a/pl/consult.yap b/pl/consult.yap
index 7bd7ec4ac..e0d163d02 100644
--- a/pl/consult.yap
+++ b/pl/consult.yap
@@ -214,8 +214,8 @@ load_files(Files,Opts) :-
 '$lf_option'(silent, 8, _).
 '$lf_option'(skip_unix_header, 9, true).
 '$lf_option'(compilation_mode, 10, Flag) :-
-    '$access_yap_flags'(11,YF),
-    ( YF == 0 -> Flag = compact ; Flag = source ).
+	current_prolog_flag(source, YFlag),
+	( YFlag == false -> Flag = compact ; Flag = source ).
 '$lf_option'(consult, 11, reconsult).
 '$lf_option'(stream, 12, _).
 '$lf_option'(register, 13, true).
@@ -227,7 +227,8 @@ load_files(Files,Opts) :-
 '$lf_option'('$location', 19, _).
 '$lf_option'(dialect, 20, yap).
 '$lf_option'(format, 21, source).
-'$lf_option'(redefine_module, 22, false).
+'$lf_option'(redefine_module, 22, Warn) :-
+	( var(Warn) ->	current_prolog_flag( redefine_warnings, Redefine ), Redefine = Warn ; true )).
 '$lf_option'(reexport, 23, false).
 '$lf_option'(sandboxed, 24, false).
 '$lf_option'(scope_settings, 25, false).
@@ -436,13 +437,15 @@ load_files(Files,Opts) :-
         ;
 	stream_property(Stream, file_name(Y))
     ), !,
-    ( '$size_stream'(Stream, Pos) -> true ; Pos = 0),
+ %   start_low_level_trace,
+    ( file_size(Stream, Pos) -> true ; Pos = 0),
     '$set_lf_opt'('$source_pos', TOpts, Pos),
     '$lf_opt'(reexport, TOpts, Reexport),
     '$lf_opt'(if, TOpts, If),
     ( var(If) -> If = true ; true ),
     '$lf_opt'(imports, TOpts, Imports),
     '$start_lf'(If, Mod, Stream, TOpts, File, Y, Reexport, Imports),
+%	stop_low_level_trace,
     close(Stream).
 '$lf'(X, _, Call, _) :-
     '$do_error'(permission_error(input,stream,X),Call).
@@ -461,6 +464,7 @@ load_files(Files,Opts) :-
     '$reexport'( TOpts, ParentF, Reexport, Imports, File ).
 '$start_lf'(_, Mod, PlStream, TOpts, _UserFile, File, Reexport, ImportList) :-
     % check if there is a qly file
+%	start_low_level_trace,
 	'$absolute_file_name'(File,[access(read),file_type(qly),file_errors(fail),solutions(first),expand(true)],F,qload_file(File)),
     open( F, read, Stream , [type(binary)] ),
      H0 is heapused, '$cputime'(T0,_),
@@ -483,6 +487,7 @@ load_files(Files,Opts) :-
        '$lf_opt'('$location', TOpts, ParentF:_Line),
        '$reexport'( TOpts, ParentF, Reexport, ImportList, File ),
        print_message(Verbosity, loaded( loaded, F, M, T, H)),
+%	stop_low_level_trace,
        '$exec_initialisation_goals'
     ;
        close( Stream),
@@ -503,7 +508,7 @@ loaded, otherwise advertises the user about the existing name clashes
 are not public remain invisible.
 
 When the files are not module files, ensure_loaded/1 loads them
-if they have not been loaded before, and naes nothing otherwise.
+if they have not been loaded before, and does nothing otherwise.
 
  _F_ must be a list containing the names of the files to load.
 */
@@ -543,7 +548,7 @@ consult(Fs) :-
 	'$consult'(Fs, M0).
 
 '$consult'(Fs,Module) :-
-	'$access_yap_flags'(8, 2), % SICStus Prolog compatibility
+	current_prolog_flag(language_mode, iso), % SICStus Prolog compatibility
 	!,
 	'$load_files'(Module:Fs,[],consult(Fs)).
 '$consult'(Fs, Module) :-
@@ -646,6 +651,9 @@ db_files(Fs) :-
 
 
 '$do_lf'(ContextModule, Stream, UserFile, File,  TOpts) :-
+	stream_property(OldStream, alias(loop_stream) ),
+	'$lf_opt'(encoding, TOpts, Encoding),
+	set_stream( Stream, [alias(loop_stream), encoding(Encoding)] ),
 	'$lf_opt'('$context_module', TOpts, ContextModule),
 	'$lf_opt'(reexport, TOpts, Reexport),
 	'$msg_level'( TOpts, Verbosity),
@@ -653,8 +661,6 @@ db_files(Fs) :-
 	'$nb_getval'('$qcompile', ContextQCompiling, ContextQCompiling = never),
 	nb_setval('$qcompile', QCompiling),
 %	format( 'I=~w~n', [Verbosity=UserFile] ),
-	'$lf_opt'(encoding, TOpts, Encoding),
-	'$set_encoding'(Stream, Encoding),
 	% export to process
 	b_setval('$lf_status', TOpts),
 	'$reset_if'(OldIfLevel),
@@ -666,8 +672,7 @@ db_files(Fs) :-
 	'$loaded'(File, UserFile, SourceModule, ParentF, Line, Reconsult0, Reconsult, Dir, Opts),
         working_directory(OldD, Dir),
 	H0 is heapused, '$cputime'(T0,_),
-	'$set_current_loop_stream'(OldStream, Stream),
-	'$swi_current_prolog_flag'(generate_debug_info, GenerateDebug),
+	current_prolog_flag(generate_debug_info, GenerateDebug),
 	'$lf_opt'(compilation_mode, TOpts, CompMode),
 	'$comp_mode'(OldCompMode, CompMode),
 	recorda('$initialisation','$',_),
@@ -705,8 +710,8 @@ db_files(Fs) :-
 	    ;
 	    true
 	),
-	'$set_current_loop_stream'(Stream, OldStream),
-	'$swi_set_prolog_flag'(generate_debug_info, GenerateDebug),
+	set_stream( OldStream, alias(loop_stream) ),
+	set_prolog_flag(generate_debug_info, GenerateDebug),
 	'$comp_mode'(_CompMode, OldCompMode),
 	working_directory(_,OldD),
 	% surely, we were in run mode or we would not have included the file!
@@ -735,13 +740,13 @@ db_files(Fs) :-
 '$msg_level'( TOpts, Verbosity) :-
 	'$lf_opt'(autoload, TOpts, AutoLoad),
 	AutoLoad == true,
-	'$swi_current_prolog_flag'(verbose_autoload, false), !,
+	current_prolog_flag(verbose_autoload, false), !,
 	Verbosity = silent.
 '$msg_level'( _TOpts, Verbosity) :-
-	'$swi_current_prolog_flag'(verbose_load, false), !,
+	current_prolog_flag(verbose_load, false), !,
 	Verbosity = silent.
 '$msg_level'( _TOpts, Verbosity) :-
-	'$swi_current_prolog_flag'(verbose, silent), !,
+	current_prolog_flag(verbose, silent), !,
 	Verbosity = silent.
 '$msg_level'( TOpts, Verbosity) :-
 	'$lf_opt'(silent, TOpts, Silent),
@@ -845,17 +850,16 @@ db_files(Fs) :-
 	  true ;
 	  '$do_error'(permission_error(input,stream,Y),include(X))
 	),
-	'$set_current_loop_stream'(OldStream, Stream),
 	H0 is heapused, '$cputime'(T0,_),
 	working_directory(Dir, Dir),
+	'$lf_opt'(encoding, TOpts, Encoding),
+	set_stream(Stream, [encoding(Encoding),alias(loop_stream)] ),
 	'$loaded'(Y, X,  Mod, OldY, L, include, _, Dir, []),
         ( '$nb_getval'('$included_file', OY, fail ) -> true ; OY = [] ),
-	'$lf_opt'(encoding, TOpts, Encoding),
-	'$set_encoding'(Stream, Encoding),
 	nb_setval('$included_file', Y),
 	print_message(Verbosity, loading(including, Y)),
 	'$loop'(Stream,Status),
-	'$set_current_loop_stream'(Stream, OldStream),
+	set_stream(OldStream, alias(loop_stream) ),
 	close(Stream),
 	H is heapused-H0, '$cputime'(TF,_), T is TF-T0,
 	print_message(Verbosity, loaded(included, Y, Mod, T, H)),
@@ -870,16 +874,16 @@ db_files(Fs) :-
 	'$init_win_graphics',
     fail.
 '$do_startup_reconsult'(X) :-
-	( '$access_yap_flags'(15, 0) ->
+	( current_prolog_flag(language_mode, yap) ->
 	  '$system_catch'(load_files(X, [silent(true)]), Module, Error, '$Error'(Error))
 	;
-	  '$swi_set_prolog_flag'(verbose, silent),
+	  set_prolog_flag(verbose, silent),
 	  '$system_catch'(load_files(X, [silent(true),skip_unix_header(true)]),Module,_,fail)
 	;
 	  true
 	),
 	!,
-	( '$access_yap_flags'(15, 0) -> true ; halt).
+	( current_prolog_flag(language_mode, yap) -> true ; halt).
 '$do_startup_reconsult'(_).
 
 '$skip_unix_header'(Stream) :-
@@ -993,8 +997,7 @@ prolog_load_context(stream, Stream) :-
         '$nb_getval'('$consulting_file', _, fail),
         '$current_loop_stream'(Stream).
 prolog_load_context(term_position, Position) :-
-        '$current_loop_stream'(Stream),
-        stream_property(Stream, position(Position) ).
+	stream_property( Stream, [alias(loop_stream),position(Position)] ).
 
 
 % if the file exports a module, then we can
@@ -1075,13 +1078,6 @@ prolog_load_context(term_position, Position) :-
 		  true ),
 	recorda('$lf_loaded','$lf_loaded'( F, M, Reconsult, UserFile, OldF, Line, Opts), _).
 
-'$set_encoding'(Encoding) :-
-	'$current_loop_stream'(Stream),
-	'$set_encoding'(Stream, Encoding).
-
-'$set_encoding'(Stream, Encoding) :-
-	( Encoding == default -> true ; set_stream(Stream, encoding(Encoding)) ).
-
 /** @pred make is det
 
 SWI-Prolog originally included this built-in as a Prolog version of the Unix `make`
@@ -1099,14 +1095,6 @@ make.
 
 make_library_index(_Directory).
 
-'$file_name'(Stream,F) :-
-	stream_property(Stream, file_name(F)), !.
-'$file_name'(user_input,user_input) :- !.
-'$file_name'(user_output,user_ouput) :- !.
-'$file_name'(user_error,user_error) :- !.
-'$file_name'(_,[]).
-
-
 '$fetch_stream_alias'(OldStream,Alias) :-
 	stream_property(OldStream, alias(Alias)), !.
 
@@ -1116,22 +1104,6 @@ make_library_index(_Directory).
 	assert_static(Clause).
 
 
-'$set_current_loop_stream'(OldStream, Stream) :-
-	'$current_loop_stream'(OldStream), !,
-	'$new_loop_stream'(Stream).
-'$set_current_loop_stream'(_OldStream, Stream) :-
-	'$new_loop_stream'(Stream).
-
-'$new_loop_stream'(Stream) :-
-	(var(Stream) ->
-	    nb_delete('$loop_stream')
-	;
-	    nb_setval('$loop_stream',Stream)
-	).
-
-'$current_loop_stream'(Stream) :-
-	'$nb_getval'('$loop_stream',Stream, fail).
-
 exists_source(File) :-
 	'$full_filename'(File, _AbsFile, exists_source(File)).
 
@@ -1664,15 +1636,15 @@ End of conditional compilation.
 	nb_setval('$assert_all',on).
 '$comp_mode'(OldCompMode, source) :-
 	'$fetch_comp_status'(OldCompMode),
-	'$set_yap_flags'(11,1).
+	set_prolog_flag(source, true).
 '$comp_mode'(OldCompMode, compact) :-
 	'$fetch_comp_status'(OldCompMode),
-	'$set_yap_flags'(11,0).
+	set_prolog_flag(source, false).
 
 '$fetch_comp_status'(assert_all) :-
 	'$nb_getval'('$assert_all',on, fail), !.
 '$fetch_comp_status'(source) :-
-	 '$access_yap_flags'(11,1), !.
+	 current_prolog_flag(source, true), !.
 '$fetch_comp_status'(compact).
 
 consult_depth(LV) :- '$show_consult_level'(LV).
diff --git a/pl/debug.yap b/pl/debug.yap
index 43c0feca3..7d1711da0 100644
--- a/pl/debug.yap
+++ b/pl/debug.yap
@@ -148,8 +148,8 @@ mode and the existing spy-points, when the debugger is on.
 	  ).
  '$do_suspy'(S, F, N, T, M) :-
 	  '$system_predicate'(T,M),
-	 '$flags'(T,M,F,F),
-	 F /\ 0x118dd080 =\= 0,
+	  '$predicate_flags'(T,M,F,F),
+	  F /\ 0x118dd080 =\= 0,
 	  ( S = spy ->
 	      '$do_error'(permission_error(access,private_procedure,T),spy(M:F/N))
 	  ;
@@ -243,16 +243,16 @@ debug :-
 
  '$start_debugging'(Mode) :-
 	 (Mode == on ->
-	  '$swi_set_prolog_flag'(debug, true)
+	  set_prolog_flag(debug, true)
 	 ;
-	  '$swi_set_prolog_flag'(debug, false)
+	  set_prolog_flag(debug, false)
 	 ),
 	 nb_setval('$debug_run',off),
 	 nb_setval('$debug_jump',false).
 
  nodebug :-
 	 '$init_debugger',
-	 '$swi_set_prolog_flag'(debug, false),
+	 set_prolog_flag(debug, false),
 	 nb_setval('$trace',off),
 	 print_message(informational,debug(off)).
 
@@ -402,7 +402,7 @@ debugging :-
 	'$init_debugger',
 	prolog:debug_action_hook(nospyall), !.
 debugging :-
-	( '$swi_current_prolog_flag'(debug, true) ->
+	( current_prolog_flag(debug, true) ->
 	    print_message(help,debug(debug))
 	    ;
 	    print_message(help,debug(off))
@@ -572,7 +572,7 @@ top-level. YAP disactivates debug mode, but spypoints are not removed.
 + `n` - nodebug
 
     stop debugging and continue execution. The command will not clear active
-spy-points.
+§spy-points.
 
 + `e` - exit
 
@@ -667,7 +667,7 @@ be lost.
 %
 % $spy may be called from user code, so be careful.
 '$spy'([Mod|G]) :-
-	'$swi_current_prolog_flag'(debug, false), !,
+	current_prolog_flag(debug, false), !,
 	'$execute_nonstop'(G,Mod).
 '$spy'([Mod|G]) :-
 	CP is '$last_choice_pt',
@@ -917,7 +917,7 @@ be lost.
 	'$spycall_expanded'(G, M, CalledFromDebugger, InRedo).
 
 '$spycall_expanded'(G, M, _CalledFromDebugger, InRedo) :-
-	'$flags'(G,M,F,F),
+	'$predicate_flags'(G,M,F,F),
 	F /\ 0x08402000 =\= 0, !, % dynamic procedure, logical semantics, or source
 	% use the interpreter
 	CP is '$last_choice_pt',
@@ -955,7 +955,7 @@ be lost.
 	).
 
 '$tabled_predicate'(G,M) :-
-	'$flags'(G,M,F,F),
+	'$predicate_flags'(G,M,F,F),
 	F /\ 0x00000040 =\= 0.
 
 %'$trace'(P,G,Module,L,Deterministic) :-
@@ -964,7 +964,7 @@ be lost.
 	% at this point we are done with leap or skip
 	nb_setval('$debug_run',off),
 	% make sure we run this code outside debugging mode.
-	'$swi_set_prolog_flag'(debug, false),
+	set_prolog_flag(debug, false),
 	repeat,
 	'$trace_msg'(P,G,Module,L,Deterministic),
 	(
@@ -977,13 +977,13 @@ be lost.
 	),
 	(Debug = on
 	->
-	 '$swi_set_prolog_flag'(debug, true)
+	 set_prolog_flag(debug, true)
 	;
 	 Debug = zip
 	->
-	 '$swi_set_prolog_flag'(debug, true)
+	 set_prolog_flag(debug, true)
 	;
-	 '$swi_set_prolog_flag'(debug, false)
+	 set_prolog_flag(debug, false)
 	),
 	!.
 
@@ -1027,10 +1027,10 @@ be lost.
 '$action'(0'!,_,_,_,_,_) :- !,			% ! 'g		execute
 	read(debugger_input, G),
 	% don't allow yourself to be caught by creep.
-	'$swi_current_prolog_flag'(debug, OldDeb),
-	 '$swi_set_prolog_flag'(debug, false),
+	current_prolog_flag(debug, OldDeb),
+	 set_prolog_flag(debug, false),
 	( '$execute'(G) -> true ; true),
-	'$swi_set_prolog_flag'(debug, OldDeb),
+	set_prolog_flag(debug, OldDeb),
 %	'$skipeol'(0'!),                        % '
 	fail.
 '$action'(0'<,_,_,_,_,_) :- !,			% <'Depth
@@ -1109,7 +1109,7 @@ be lost.
 	nodebug.
 '$action'(0'r,_,CallId,_,_,_) :- !,		        % 'r		retry
         '$scan_number'(0'r,CallId,ScanNumber),		% '
-	'$swi_set_prolog_flag'(debug, true),
+	set_prolog_flag(debug, true),
 	throw(error('$retry_spy'(ScanNumber),[])).
 '$action'(0's,P,CallNumber,_,_,on) :- !,		% 's		skip
 	'$skipeol'(0's),				% '
diff --git a/pl/directives.yap b/pl/directives.yap
index 761596f2a..59f3cb1f9 100644
--- a/pl/directives.yap
+++ b/pl/directives.yap
@@ -115,8 +115,8 @@
     '$exec_directive'(G, Mode, M, VL, Pos).
 
 '$save_directive'(G, Mode, M, VL, Pos) :-
-    prolog_load_context(file, FileName), !,
-    recordz('$directive', directive(FileName,M:G, Mode, VL, Pos),_).
+	prolog_load_context(file, FileName), !,
+	recordz('$directive', directive(FileName,M:G, Mode, VL, Pos),_).
 
 '$exec_directive'(multifile(D), _, M, _, _) :-
 	'$system_catch'('$multifile'(D, M), M,
diff --git a/pl/flags.yap b/pl/flags.yap
index abfccfddb..118c1b228 100644
--- a/pl/flags.yap
+++ b/pl/flags.yap
@@ -26,623 +26,6 @@
         yap_flag/2,
         yap_flag/3], []).
 
-/** @defgroup Flags  YAP Execution Flags
-    @ingroup builtins
-    @{
-*/
-
-:- use_system_module( '$_boot', ['$prompt_alternatives_on'/1]).
-
-:- use_system_module( '$_checker', ['$syntax_check_discontiguous'/2,
-        '$syntax_check_multiple'/2,
-        '$syntax_check_single_var'/2]).
-
-:- use_system_module( '$_control', ['$set_toplevel_hook'/1]).
-
-:- use_system_module( '$_errors', ['$do_error'/2]).
-
-:- use_system_module( '$_yio', ['$default_expand'/1,
-        '$set_default_expand'/1]).
-
-yap_flag(V,Out) :-
-	'$user_defined_flag'(V,_,_,_),
-	(nonvar(V) ->
-	 !
-	;
-	 true
-	),
-	'$user_flag_value'(V, Out).
-
-yap_flag(V,Out) :-
-	( var(V) ->
-	  '$swi_current_prolog_flag'(V, Out)
-        ;
-	  '$swi_current_prolog_flag'(V, Current)
-        ->
-	  (var(Out) ->
-	      Current = Out
-	  ;
-	      '$swi_set_prolog_flag'(V, Out)
-	  )
-        ).
-yap_flag(V,Out) :-
-	var(V), !,
-	'$show_yap_flag_opts'(V,Out).
-
-% do or do not machine code
-yap_flag(fast,on) :- set_value('$fast',true).
-yap_flag(fast,off) :- !, set_value('$fast',[]).
-
-% hide/unhide atoms
-yap_flag(hide,Atom) :- !, hide(Atom).
-yap_flag(unhide,Atom) :- !, unhide(Atom).
-
-% control garbage collection
-yap_flag(gc,V) :-
-	var(V), !,
-	( get_value('$gc',[]) -> V = off ; V = on).
-yap_flag(gc,on) :- !, set_value('$gc',true).
-yap_flag(gc,off) :- !, set_value('$gc',[]).
-
-yap_flag(gc_margin,N) :- 
-	( var(N) -> 
-	    get_value('$gc_margin',N)
-	;
-	integer(N), N >=0  ->
-	    set_value('$gc_margin',N)
-	;
-	    '$do_error'(domain_error(flag_value,gc_margin+X),yap_flag(gc_margin,X))
-	).
-yap_flag(gc_trace,V) :-
-	var(V), !,
-	get_value('$gc_trace',N1),
-	get_value('$gc_verbose',N2),
-	get_value('$gc_very_verbose',N3),
-	'$yap_flag_show_gc_tracing'(N1, N2, N3, V).
-yap_flag(gc_trace,on) :- !,
-	set_value('$gc_trace',true),
-	set_value('$gc_verbose',[]),
-	set_value('$gc_very_verbose',[]).
-yap_flag(gc_trace,verbose) :- !,
-	set_value('$gc_trace',[]),
-	set_value('$gc_verbose',true),
-	set_value('$gc_very_verbose',[]).
-yap_flag(gc_trace,very_verbose) :- !,
-	set_value('$gc_trace',[]),
-	set_value('$gc_verbose',true),
-	set_value('$gc_very_verbose',true).
-yap_flag(gc_trace,off) :-
-	set_value('$gc_trace',[]),
-	set_value('$gc_verbose',[]),
-	set_value('$gc_very_verbose',[]).
-yap_flag(syntax_errors, V) :- var(V), !,
-	'$get_read_error_handler'(V).
-yap_flag(syntax_errors, Option) :-
-	'$set_read_error_handler'(Option).
-% compatibility flag
-yap_flag(enhanced,on) :- !, set_value('$enhanced',true).
-yap_flag(enhanced,off) :- set_value('$enhanced',[]).
-
-% compatibility flag
-yap_flag(agc_margin,Margin) :-
-	'$agc_threshold'(Margin).
-
-
-%
-% show state of $
-%
-yap_flag(dollar_as_lower_case,V) :-
-	var(V), !,
-	'$type_of_char'(36,T),
-	(T = 3 -> V = on ; V = off).
-%
-% make $a a legit atom
-%
-yap_flag(dollar_as_lower_case,on) :- !,
-	'$change_type_of_char'(36,3).
-%
-% force quoting of '$a'
-%
-yap_flag(dollar_as_lower_case,off) :- 
-	'$change_type_of_char'(36,7).
-
-yap_flag(call_counting,X) :- (var(X); X = on; X = off), !,
-	'$is_call_counted'(X).
-
-:- set_value('$associate',yap).
-
-yap_flag(associate,X) :-
-	var(X), !,
-	get_value('$associate',X).
-yap_flag(associate,X) :-
-	atom(X), !,
-	set_value('$associate',X).
-yap_flag(associate,X) :-
-	'$do_error'(type_error(atom,X),associate(X)).
-
-% do or do not indexation
-yap_flag(index,X) :- var(X),
-	'$access_yap_flags'(19, X1),
-	'$transl_to_index_mode'(X1,X), !.
-yap_flag(index,X)  :-
-	'$transl_to_index_mode'(X1,X), !,
-	'$set_yap_flags'(19,X1).
-yap_flag(index,X) :-
-	'$do_error'(domain_error(flag_value,index+X),yap_flag(index,X)).
-
-% do or do not indexation
-yap_flag(index_sub_term_search_depth,X) :- 
-    var(X),
-    '$access_yap_flags'(23, X), !.
-yap_flag(index_sub_term_search_depth,X)  :-
-    integer(X),
-    X > 0,
-    '$set_yap_flags'(23,X).
-yap_flag(index_sub_term_search_depth,X)  :-
-    \+ integer(X),
-    '$do_error'(type_error(integer,X),yap_flag(index_sub_term_search_depth,X)).
-yap_flag(index_sub_term_search_depth,X) :-
-    '$do_error'(domain_error(out_of_range,index_sub_term_search_depth+X),yap_flag(index_sub_term_search_depth,X)).
-
-% tabling mode
-yap_flag(tabling_mode,Options) :- 
-   var(Options), !,
-   '$access_yap_flags'(20,Options).
-yap_flag(tabling_mode,[]) :- !,
-   yap_flag(tabling_mode,default).
-yap_flag(tabling_mode,[HOption|TOption]) :- !,
-   yap_flag(tabling_mode,TOption),
-   yap_flag(tabling_mode,HOption).
-yap_flag(tabling_mode,Option) :-
-   '$transl_to_yap_flag_tabling_mode'(Flag,Option), !,
-   '$set_yap_flags'(20,Flag).
-yap_flag(tabling_mode,Options) :-
-   '$do_error'(domain_error(flag_value,tabling_mode+Options),yap_flag(tabling_mode,Options)).
-
-yap_flag(informational_messages,X) :- var(X), !,
-	 yap_flag(verbose, X).
-
-yap_flag(version,X) :-
-	var(X), !,
-	get_value('$version_name',X).
-yap_flag(version,X) :-
-	'$do_error'(permission_error(modify,flag,version),yap_flag(version,X)).
-
-/* ISO Core Revision DTR: new float flags
-
-yap_flag(float_mantissa_digits,X) :-
-	var(X), !,
-	?????
-yap_flag(float_mantissa_digits,X) :-
-	integer(X), X > 0, !,
-	'$do_error'(permission_error(modify,flag,float_mantissa_digits),yap_flag(float_mantissa_digits,X)).
-yap_flag(float_mantissa_digits,X) :-
-	'$do_error'(domain_error(flag_value,float_mantissa_digits+X),yap_flag(float_mantissa_digits,X)).
-
-yap_flag(float_epsilon,X) :-
-	var(X), !,
-	?????
-yap_flag(float_epsilon,X) :-
-	float(X), X > 0, !,
-	'$do_error'(permission_error(modify,flag,float_epsilon),yap_flag(float_epsilon,X)).
-yap_flag(float_epsilon,X) :-
-	'$do_error'(domain_error(flag_value,float_epsilon+X),yap_flag(float_epsilon,X)).
-
-yap_flag(float_min_exponent,X) :-
-	var(X), !,
-	?????
-yap_flag(float_min_exponent,X) :-
-	integer(X), X > 0, !,
-	'$do_error'(permission_error(modify,flag,float_min_exponent),yap_flag(float_min_exponent,X)).
-yap_flag(float_epsilon,X) :-
-	'$do_error'(domain_error(flag_value,float_min_exponent+X),yap_flag(float_min_exponent,X)).
-
-yap_flag(float_max_exponent,X) :-
-	var(X), !,
-	?????
-yap_flag(float_max_exponent,X) :-
-	integer(X), X > 0, !,
-	'$do_error'(permission_error(modify,flag,float_max_exponent),yap_flag(flo
-									     at_max_exponent,X)).
-yap_flag(float_max_exponent,X) :-
-	'$do_error'(domain_error(flag_value,float_max_exponent+X),yap_flag(float_max_exponent,X)).
-*/
-
-yap_flag(n_of_integer_keys_in_db,X) :-
-	var(X), !,
-	'$resize_int_keys'(X).
-yap_flag(n_of_integer_keys_in_db,X) :- integer(X), X > 0, !,
-	'$resize_int_keys'(X).
-yap_flag(n_of_integer_keys_in_db,X) :-
-	'$do_error'(domain_error(flag_value,n_of_integer_keys_in_db+X),yap_flag(n_of_integer_keys_in_db,X)).
-
-yap_flag(n_of_integer_keys_in_bb,X) :-
-	var(X), !,
-	'$resize_bb_int_keys'(X).
-yap_flag(n_of_integer_keys_in_bb,X) :- integer(X), X > 0, !,
-	'$resize_bb_int_keys'(X).
-yap_flag(n_of_integer_keys_in_bb,X) :-
-	'$do_error'(domain_error(flag_value,n_of_integer_keys_in_bb+X),yap_flag(n_of_integer_keys_in_bb,X)).
-
-yap_flag(profiling,X) :- (var(X); X = on; X = off), !,
-	'$is_profiled'(X).
-
-yap_flag(strict_iso,OUT) :-
-	var(OUT), !,
-	'$access_yap_flags'(9,X),
-	'$transl_to_on_off'(X,OUT).
-yap_flag(strict_iso,on) :- !,
-	yap_flag(language,iso),
-	'$transl_to_on_off'(X,on),
-	'$set_yap_flags'(9,X).
-yap_flag(strict_iso,off) :- !,
-	'$transl_to_on_off'(X,off),
-	'$set_yap_flags'(9,X).
-yap_flag(strict_iso,X) :-
-	'$do_error'(domain_error(flag_value,strict_iso+X),yap_flag(strict_iso,X)).
-
-yap_flag(variable_names_may_end_with_quotes,OUT) :-
-	var(OUT), !,
-	'$access_yap_flags'(21,X),
-	'$transl_to_on_off'(X,OUT).
-yap_flag(variable_names_may_end_with_quotes,on) :- !,
-	'$transl_to_on_off'(X,on),
-	'$set_yap_flags'(21,X).
-yap_flag(variable_names_may_end_with_quotes,off) :- !,
-	'$transl_to_on_off'(X,off),
-	'$set_yap_flags'(21,X).
-yap_flag(variable_names_may_end_with_quotes,X) :-
-	'$do_error'(domain_error(flag_value,strict_iso+X),yap_flag(strict_iso,X)).
-
-yap_flag(language,X) :-
-	var(X), !,
-	'$access_yap_flags'(8, X1),
-	'$trans_to_lang_flag'(X1,X).
-yap_flag(language,X) :-
-	'$trans_to_lang_flag'(N,X), !,
-	'$set_yap_flags'(8,N),
-	'$adjust_language'(X).
-yap_flag(language,X) :-
-	'$do_error'(domain_error(flag_value,language+X),yap_flag(language,X)).
-
-yap_flag(discontiguous_warnings,X) :-
-	var(X), !,
-	style_check(?(Disc)),
-	( Disc = +discontiguous,
-	  X = on
-	;
-	  Disc = -discontiguous,
-	  X = off
-	), !.
-yap_flag(discontiguous_warnings,X) :-
-	'$transl_to_on_off'(_,X), !,
-	(X == on -> 
-	    style_check(discontiguous)
-	;
-	    style_check(-discontiguous)
-	).
-yap_flag(discontiguous_warnings,X) :-
-	'$do_error'(domain_error(flag_value,discontiguous_warnings+X),yap_flag(discontiguous_warnings,X)).
-
-yap_flag(redefine_warnings,X) :-
-	var(X), !,
-	style_check(?(Disc)),
-	( Disc = +multiple,
-	  X = on
-	;
-	  Disc = -multiple,
-	  X = off
-	), !.
-yap_flag(redefine_warnings,X) :-
-	'$transl_to_on_off'(_,X), !,
-	(X == on -> 
-	    style_check(multiple)
-	;
-	    style_check(-multiple)
-	).
-yap_flag(redefine_warnings,X) :-
-	'$do_error'(domain_error(flag_value,redefine_warnings+X),yap_flag(redefine_warnings,X)).
-
-yap_flag(chr_toplevel_show_store,X) :-
-	var(X), !,
-	'$nb_getval'('$chr_toplevel_show_store', X, fail).
-yap_flag(chr_toplevel_show_store,X) :-
-	(X = true ; X = false), !,
-	nb_setval('$chr_toplevel_show_store',X).
-yap_flag(chr_toplevel_show_store,X) :-
-	'$do_error'(domain_error(flag_value,chr_toplevel_show_store+X),yap_flag(chr_toplevel_show_store,X)).
-
-yap_flag(qcompile,X) :-
-	var(X), !,
-	'$nb_getval'('$qcompile', X, X=never).
-yap_flag(qcompile,X) :-
-	(X == never ; X == auto ; X == large ; X == part), !,
-	nb_setval('$qcompile',X).
-yap_flag(qcompile,X) :-
-	'$do_error'(domain_error(flag_value,qcompile+X),yap_flag(qcompile,X)).
-
-yap_flag(source,X) :-
-	var(X), !,
-	source_mode( X, X ).
-yap_flag(source,X) :-
-	(X == off -> true ; X == on), !,
-	source_mode( _, X ).
-yap_flag(source,X) :-
-	'$do_error'(domain_error(flag_value,source+X),yap_flag(source,X)).
-
-yap_flag(open_expands_filename,Expand) :-
-	var(Expand), !,
-	'$default_expand'(Expand).
-yap_flag(open_expands_filename,Expand) :-
-	'$set_default_expand'(Expand).
-
-yap_flag(single_var_warnings,X) :-
-	var(X), !,
-	style_check(?(Disc)),
-	( Disc = +singletons,
-	  X = on
-	;
-	  Disc = -singletons,
-	  X = off
-	), !.
-yap_flag(single_var_warnings,X) :-
-	'$transl_to_on_off'(_,X), !,
-	(X == on ->
-	     style_check(single_var)
-	;
-	     style_check(-single_var)
-	).
-yap_flag(single_var_warnings,X) :-
-	'$do_error'(domain_error(flag_value,single_var_warnings+X),yap_flag(single_var_warnings,X)).
-
-yap_flag(system_options,X) :-
-	'$system_options'(X).
-	
-yap_flag(update_semantics,X) :-
-	var(X), !,
-	( '$log_upd'(I) -> '$convert_upd_sem'(I,X) ).
-yap_flag(update_semantics,logical) :- !,
-	'$switch_log_upd'(1).
-yap_flag(update_semantics,logical_assert) :- !,
-	'$switch_log_upd'(2).
-yap_flag(update_semantics,immediate) :- !,
-	'$switch_log_upd'(0).
-yap_flag(update_semantics,X) :-
-	'$do_error'(domain_error(flag_value,update_semantics+X),yap_flag(update_semantics,X)).
-
-yap_flag(toplevel_hook,G) :-
-	var(G), !,
-	( recorded('$toplevel_hooks',G,_) -> G ; G = fail ).
-yap_flag(toplevel_hook,G) :- !,
-	'$set_toplevel_hook'(G).
-
-yap_flag(typein_module,X) :-
-	var(X), !,
-	'$current_module'(X).
-yap_flag(typein_module,X) :-
-	module(X).
-
-yap_flag(write_strings,OUT) :-
-	var(OUT), !,
-	'$access_yap_flags'(13,X),
-	'$transl_to_on_off'(X,OUT).
-yap_flag(write_strings,on) :- !,
-	'$transl_to_on_off'(X,on),
-	'$set_yap_flags'(13,X).
-yap_flag(write_strings,off) :- !,
-	'$transl_to_on_off'(X,off),
-	'$set_yap_flags'(13,X).
-yap_flag(write_strings,X) :-
-	'$do_error'(domain_error(flag_value,write_strings+X),yap_flag(write_strings,X)).
-
-yap_flag(arithmetic_exceptions,OUT) :-
-	var(OUT), !,
-	'$access_yap_flags'(12,X),
-	'$transl_to_true_false'(X,OUT).
-yap_flag(arithmetic_exceptions,true) :- !,
-	'$transl_to_true_false'(X,true),
-	'$set_yap_flags'(12,X).
-yap_flag(arithmetic_exceptions,false) :- !,
-	'$transl_to_true_false'(X,false),
-	'$set_yap_flags'(12,X).
-yap_flag(arithmetic_exceptions,X) :-
-	'$do_error'(domain_error(flag_value,arithmetic_exceptions+X),yap_flag(arithmetic_exceptions,[true,false])).
-
-yap_flag(prompt_alternatives_on,OUT) :-
-	var(OUT), !,
-	'$prompt_alternatives_on'(OUT).
-yap_flag(prompt_alternatives_on,determinism) :- !,
-	'$purge_clauses'('$prompt_alternatives_on'(_),prolog),
-	'$compile'('$prompt_alternatives_on'(determinism),0,'$prompt_alternatives_on'(determinism),prolog).
-yap_flag(prompt_alternatives_on,groundness) :- !,
-	'$purge_clauses'('$prompt_alternatives_on'(_),prolog),
-	'$compile'('$prompt_alternatives_on'(groundness),0,'$prompt_alternatives_on'(groundness),prolog).
-yap_flag(prompt_alternatives_on,X) :-
-	'$do_error'(domain_error(flag_value,prompt_alternatives_on+X),yap_flag(prompt_alternatives_on,X)).
-
-yap_flag(stack_dump_on_error,OUT) :-
-	var(OUT), !,
-	'$access_yap_flags'(17,X),
-	'$transl_to_on_off'(X,OUT).
-yap_flag(stack_dump_on_error,on) :- !,
-'$transl_to_on_off'(X,on),
-	'$set_yap_flags'(17,X).
-yap_flag(stack_dump_on_error,off) :- !,
-	'$transl_to_on_off'(X,off),
-	'$set_yap_flags'(17,X).
-yap_flag(stack_dump_on_error,X) :-
-	'$do_error'(domain_error(flag_value,stack_dump_on_error+X),yap_flag(stack_dump_on_error,X)).
-
-yap_flag(user_input,OUT) :-
-	var(OUT), !,
-	stream_property(OUT,alias(user_input)).
-yap_flag(user_input,Stream) :-
-	set_stream(Stream, alias(user_input)).
-
-yap_flag(user_output,OUT) :-
-	var(OUT), !,
-	stream_property(OUT,alias(user_output)).
-yap_flag(user_output,Stream) :-
-	set_stream(Stream, alias(user_output)).
-
-yap_flag(user_error,OUT) :-
-	var(OUT), !,
-	stream_property(OUT,alias(user_error)).
-yap_flag(user_error,Stream) :-
-	set_stream(Stream, alias(user_error)).
-
-yap_flag(debugger_print_options,OUT) :-
-	var(OUT),
-	recorded('$print_options','$debugger'(OUT),_), !.
-yap_flag(debugger_print_options,Opts) :-
-	recorda('$print_options','$debugger'(Opts),_).
-
-:- recorda('$print_options','$debugger'([quoted(true),numbervars(true),portrayed(true),max_depth(10)]),_).
-
-yap_flag(toplevel_print_options,OUT) :-
-	var(OUT),
-	recorded('$print_options','$toplevel'(OUT),_), !.
-yap_flag(toplevel_print_options,Opts) :-
-	recorda('$print_options','$toplevel'(Opts),_).
-
-:- recorda('$print_options','$toplevel'([quoted(true),numbervars(true),portrayed(true)]),_).
-
-yap_flag(host_type,X) :-
-	'$host_type'(X).
-
-yap_flag(host_type,X) :-
-	'$host_type'(X).
-
-yap_flag(argv,X) :-
-	'$argv'(X).
-
-yap_flag(os_argv,X) :-
-    '$os_argv'(X).
-
-yap_flag(float_format,X) :-
-	var(X), !,
-	'$float_format'(X).
-yap_flag(float_format,X) :-
-	atom(X), !,
-	'$float_format'(X).
-yap_flag(float_format,X) :-
-	'$do_error'(type_error(atom,X),yap_flag(float_format,X)).
-
-yap_flag(max_workers,X) :-
-	var(X), !,
-	'$max_workers'(X).
-yap_flag(max_workers,X) :-
-	integer(X), X > 0, !,
-	'$do_error'(permission_error(modify,flag,max_workers),yap_flag(max_workers,X)).
-yap_flag(max_workers,X) :-
-	'$do_error'(domain_error(flag_value,max_workers+X),yap_flag(max_workers,X)).
-
-yap_flag(max_threads,X) :-
-	var(X), !,
-	'$max_threads'(X).
-yap_flag(max_threads,X) :-
-	integer(X), X > 0, !,
-	'$do_error'(permission_error(modify,flag,max_threads),yap_flag(max_threads,X)).
-yap_flag(max_threads,X) :-
-	'$do_error'(domain_error(flag_value,max_threads+X),yap_flag(max_threads,X)).
-
-% should match definitions in Yap.h
-'$transl_to_index_mode'(0, off).
-'$transl_to_index_mode'(1, single).
-'$transl_to_index_mode'(2, compact).
-'$transl_to_index_mode'(3, multi).
-'$transl_to_index_mode'(3, on). % default is multi argument indexing
-'$transl_to_index_mode'(4, max).
-
-
-% should match with code in stdpreds.c
-'$transl_to_yap_flag_tabling_mode'(0,default).
-'$transl_to_yap_flag_tabling_mode'(1,batched).
-'$transl_to_yap_flag_tabling_mode'(2,local).
-'$transl_to_yap_flag_tabling_mode'(3,exec_answers).
-'$transl_to_yap_flag_tabling_mode'(4,load_answers).
-'$transl_to_yap_flag_tabling_mode'(5,local_trie).
-'$transl_to_yap_flag_tabling_mode'(6,global_trie).
-'$transl_to_yap_flag_tabling_mode'(7,coinductive).
-
-'$system_options'(big_numbers) :-
-	'$has_bignums'.
-'$system_options'(coroutining) :-
-	'$yap_has_coroutining'.
-'$system_options'(depth_limit) :-
-	\+ '$undefined'(get_depth_limit(_), prolog).
-'$system_options'(low_level_tracer) :-
-	\+ '$undefined'(start_low_level_trace, prolog).
-'$system_options'(or_parallelism) :-
-	\+ '$undefined'('$c_yapor_start', prolog).
-'$system_options'(rational_trees) :-
-	'$yap_has_rational_trees'.
-'$system_options'(readline) :-
-	'$swi_current_prolog_flag'(readline, true).
-'$system_options'(tabling) :-
-	\+ '$undefined'('$c_table'(_,_,_), prolog).
-'$system_options'(threads) :-
-	\+ '$undefined'('$thread_join'(_), prolog).
-'$system_options'(wam_profiler) :-
-	\+ '$undefined'(reset_op_counters, prolog).
-
-'$yap_system_flag'(agc_margin).
-'$yap_system_flag'(arithmetic_exceptions).
-'$yap_system_flag'(argv).
-'$yap_system_flag'(chr_toplevel_show_store).
-'$yap_system_flag'(debugger_print_options).
-'$yap_system_flag'(discontiguous_warnings).
-'$yap_system_flag'(dollar_as_lower_case).
-%		V = fast  ;
-% '$yap_system_flag'(file_name_variables).
-% '$yap_system_flag'(fileerrors ).
-'$yap_system_flag'(float_format).
-%		V = float_mantissa_digits ;
-%		V = float_epsilon ;
-%		V = float_min_exponent ;
-%		V = float_max_exponent ;
-'$yap_system_flag'(gc   ).
-'$yap_system_flag'(gc_margin   ).
-'$yap_system_flag'(gc_trace    ).
-%	    V = hide  ;
-'$yap_system_flag'(host_type ).
-'$yap_system_flag'(index).
-'$yap_system_flag'(index_sub_term_search_depth).
-'$yap_system_flag'(tabling_mode).
-'$yap_system_flag'(informational_messages).
-'$yap_system_flag'(language).
-'$yap_system_flag'(max_workers).
-'$yap_system_flag'(max_threads).
-'$yap_system_flag'(n_of_integer_keys_in_db).
-'$yap_system_flag'(open_expands_filename).
-'$yap_system_flag'(os_argv).
-'$yap_system_flag'(profiling).
-'$yap_system_flag'(prompt_alternatives_on).
-'$yap_system_flag'(redefine_warnings).
-'$yap_system_flag'(single_var_warnings).
-'$yap_system_flag'(source).
-'$yap_system_flag'(stack_dump_on_error).
-'$yap_system_flag'(strict_iso).
-'$yap_system_flag'(syntax_errors).
-'$yap_system_flag'(system_options).
-'$yap_system_flag'(toplevel_hook).
-'$yap_system_flag'(toplevel_print_options).
-'$yap_system_flag'(typein_module).
-'$yap_system_flag'(update_semantics).
-'$yap_system_flag'(user_error).
-'$yap_system_flag'(user_input).
-'$yap_system_flag'(user_output).
-'$yap_system_flag'(variable_names_may_end_with_quotes).
-'$yap_system_flag'(version).
-'$yap_system_flag'(write_strings).
-
-'$show_yap_flag_opts'(V,Out) :-
-	'$yap_system_flag'(V),
-	yap_flag(V, Out).
-
-'$trans_to_lang_flag'(0,cprolog).
-'$trans_to_lang_flag'(1,iso).
-'$trans_to_lang_flag'(2,sicstus).
 
 '$adjust_language'(cprolog) :-
 %	'$switch_log_upd'(0),
@@ -686,218 +69,20 @@ yap_flag(max_threads,X) :-
 	unknown(_,error).
 
 
-'$convert_upd_sem'(0,immediate).
-'$convert_upd_sem'(1,logical).
-'$convert_upd_sem'(2,logical_assert).
-
-'$transl_to_true_false'(0,false).
-'$transl_to_true_false'(1,true).
-
-'$transl_to_on_off'(0,off).
-'$transl_to_on_off'(1,on).
-
-'$transl_to_rounding_function'(0,toward_zero).
-'$transl_to_rounding_function'(1,down).
-
-'$yap_flag_show_gc_tracing'(true, _, _, on) :- !.
-'$yap_flag_show_gc_tracing'(_, true, _, verbose) :- !.
-'$yap_flag_show_gc_tracing'(_, _, on, very_verbose) :- !.
-'$yap_flag_show_gc_tracing'(_, _, _, off).
-
-'$flag_check_alias'(OUT, Alias) :-
-	stream_property(OUT,alias(Alias)), !.
-	
-/** @pred current_prolog_flag(? _Flag_,- _Value_) is iso 
-
-Obtain the value for a YAP Prolog flag. Equivalent to calling
-yap_flag/2 with the second argument unbound, and unifying the
-returned second argument with  _Value_.
-
- 
-*/
-current_prolog_flag(V,Out) :-
-	var(V), !,
-	yap_flag(V,NOut),
-	NOut = Out.
-current_prolog_flag(V,Out) :-
-	atom(V), !,
-	yap_flag(V,NOut),
-	NOut = Out.
-current_prolog_flag(M:V,Out) :-
-	current_module(M), atom(V), !,
-	yap_flag(M:V,NOut),
-	NOut = Out.
-current_prolog_flag(V,Out) :-
-	'$do_error'(type_error(atom,V),current_prolog_flag(V,Out)).
-
-/** @pred set_prolog_flag(+ _Flag_,+ _Value_) is iso 
-
-
-
-Set the value for YAP Prolog flag `Flag`. Equivalent to
-calling yap_flag/2 with both arguments bound.
-
- 
-*/
-set_prolog_flag(F,V) :-
-	var(F), !,
-	'$do_error'(instantiation_error,set_prolog_flag(F,V)).
-set_prolog_flag(F,V) :-
-	var(V), !,
-	'$do_error'(instantiation_error,set_prolog_flag(F,V)).
-set_prolog_flag(M:V,Out) :-
-	current_module(M), atom(V), !,
-	'$swi_set_prolog_flag'(M:V,Out).
-set_prolog_flag(F,V) :-
-	\+ atom(F), !,
-	'$do_error'(type_error(atom,F),set_prolog_flag(F,V)).
-set_prolog_flag(F, Val) :-
-	'$swi_current_prolog_flag'(F, _), !,
-	'$swi_set_prolog_flag'(F, Val).
-set_prolog_flag(F,V) :-
-	'$yap_system_flag'(F), !,
-	yap_flag(F,V).
-set_prolog_flag(F,V) :-
-	'$swi_current_prolog_flag'(user_flags, UFlag),
-	(
-	 UFlag = silent ->
-	 create_prolog_flag(F, V, [])
-	;
-	 UFlag = warning ->
-	 print_message(warning,existence_error(prolog_flag, F)),
-	 create_prolog_flag(F, V, [])
-	;
-	 UFlag = error ->
-	 '$do_error'(existence_error(prolog_flag, F),set_prolog_flag(F,V))
-	).
-
-/** @pred prolog_flag(? _Flag_,- _OldValue_,+ _NewValue_) 
-
-
-
-Obtain the value for a YAP Prolog flag and then set it to a new
-value. Equivalent to first calling current_prolog_flag/2 with the
-second argument  _OldValue_ unbound and then calling
-set_prolog_flag/2 with the third argument  _NewValue_.
-
- 
-*/
-prolog_flag(F, Old, New) :-
-	var(F), !,
-	'$do_error'(instantiation_error,prolog_flag(F,Old,New)).
-prolog_flag(F, Old, New) :-
-	current_prolog_flag(F, Old),
-	set_prolog_flag(F, New).
-
-prolog_flag(F, Old) :-
-	current_prolog_flag(F, Old).
-
 /** @pred create_prolog_flag(+ _Flag_,+ _Value_,+ _Options_) 
 
+Create a new YAP Prolog flag.  _Options_ include
 
+   * `type(+_Type_)` with _Type_ one of `boolean`, `integer`, `float`, `atom`
+and `term` (that is, any ground term)
 
-Create a new YAP Prolog flag.  _Options_ include `type(+Type)` and `access(+Access)` with  _Access_
-one of `read_only` or `read_write` and  _Type_ one of `boolean`, `integer`, `float`, `atom`
-and `term` (that is, no type).
+   * `access(+_Access_)` with  _Access_ one of `read_only` or `read_write`
 
- 
+   * `keeep(+_Keep_) protect existing flag.
 */
 create_prolog_flag(Name, Value, Options) :-
-	'$check_flag_name'(Name, create_prolog_flag(Name, Value, Options)),
-	'$check_flag_options'(Options, Domain, RW, create_prolog_flag(Name, Value, Options)),
-	'$check_flag_value'(Value, Domain, create_prolog_flag(Name, Value, Options)),
-	retractall(prolog:'$user_defined_flag'(Name,_,_,_)),
-	assert(prolog:'$user_defined_flag'(Name,Domain,RW,Value)).
-
-'$check_flag_name'(V, G) :-
-	var(V),
-	'$do_error'(instantiation_error,G).
-'$check_flag_name'(Name, _) :-
-	atom(Name), !.
-'$check_flag_name'(Name, G) :-
-	'$do_error'(type_error(atom,Name),G).
-	
-'$check_flag_options'(O, _, _, G) :-
-	var(O),
-	'$do_error'(instantiation_error,G).
-'$check_flag_options'([], _, read_write, _) :- !.
-'$check_flag_options'([O1|Os], Domain, RW, G) :- !,
-	'$check_flag_optionsl'([O1|Os], Domain, RW, G).
-'$check_flag_options'(O, _, _, G) :-
-	'$do_error'(type_error(list,O),G).
-
-
-'$check_flag_optionsl'([], _, read_write, _G).
-'$check_flag_optionsl'([V|_Os], _Domain, _RW, G) :-
-	var(V),
-	'$do_error'(instantiation_error,G).
-'$check_flag_optionsl'([type(Type)|Os], Domain, RW, G) :- !,
-	'$check_flag_type'(Type, Domain, G),
-	'$check_flag_optionsl'(Os, _, RW, G).
-'$check_flag_optionsl'([access(Access)|Os], Domain, RW, G) :- !,
-	'$check_flag_access'(Access, RW, G),
-	'$check_flag_optionsl'(Os, Domain, _, G).
-'$check_flag_optionsl'(Os, _Domain, _RW, G) :-
-	'$do_error'(domain_error(create_prolog_flag,Os),G).
-
-'$check_flag_type'(V, _, G) :-
-	var(V),
-	'$do_error'(instantiation_error,G).
-'$check_flag_type'(boolean, boolean, _) :- !.
-'$check_flag_type'(integer, integer, _) :- !.
-'$check_flag_type'(float, float, _) :- !.
-'$check_flag_type'(atom, atom, _) :- !.
-'$check_flag_type'(term, term, _) :- !.
-'$check_flag_type'(Atom, _, G) :-
-	'$do_error'(domain_error(create_prolog_flag_option(type),Atom),G).
-
-'$check_flag_access'(V, _, G) :-
-	var(V),
-	'$do_error'(instantiation_error,G).
-'$check_flag_access'(read_write, read_write, _) :- !.
-'$check_flag_access'(read_only, read_only, _) :- !.
-'$check_flag_access'(Atom, _, G) :-
-	'$do_error'(domain_error(create_prolog_flag_option(access),Atom),G).
-
-'$user_flag_value'(F, Val) :-
-	var(Val), !,
-	'$user_defined_flag'(F,_,_,Val).
-'$user_flag_value'(F, Val) :-
-	atomic(Val), !,
-	prolog:'$user_defined_flag'(F,Domain,RW,V0),
-	(
-	 Val == V0
-	->
-	 true
-	;
-	 RW = read_only
-	->
-	 '$do_error'(permission_error(modify,flag,F),yap_flag(F,Val))
-	;
-	  '$check_flag_value'(Val, Domain, yap_flag(F,Val)),
-	  retractall(prolog:'$user_defined_flag'(F,_,_,_)),
-	  assert(prolog:'$user_defined_flag'(F,Domain,RW,Val))
-	).
-'$user_flag_value'(F, Val) :-
-	'$do_error'(type_error(atomic,Val),yap_flag(F,Val)).
-
-'$check_flag_value'(Value, _, G) :-
-	\+ ground(Value), !,
-	'$do_error'(instantiation_error,G).
-'$check_flag_value'(Value, Domain, _G) :-
-	var(Domain), !,
-	'$flag_domain_from_value'(Value, Domain).
-'$check_flag_value'(_, term, _) :- !.
-'$check_flag_value'(Value, atom, _) :-
-	atom(Value), !.
-'$check_flag_value'(Value, integer, _) :-
-	integer(Value), !.
-'$check_flag_value'(Value, float, _) :-
-	float(Value), !.
-'$check_flag_value'(true, boolean, _) :- !.
-'$check_flag_value'(false, boolean, _) :- !.
-'$check_flag_value'(Value, Domain, G) :-
-	'$do_error'(domain_error(Domain,Value),G).
+	'$flag_domain_from_value'( Value, Type ),
+	'$create_prolog_flag'(Name, Value, [type(Type)|Options]).
 
 '$flag_domain_from_value'(true, boolean) :- !.
 '$flag_domain_from_value'(false, boolean) :- !.
@@ -906,47 +91,6 @@ create_prolog_flag(Name, Value, Options) :-
 '$flag_domain_from_value'(Value, atom) :- atom(Value), !.
 '$flag_domain_from_value'(_, term).
 
-
-/** 
-   @pred source_mode(- _O_,+ _N_) 
-
-The state of source mode can either be on or off. When the source mode
-is on, all clauses are kept both as compiled code and in a "hidden"
-database.  _O_ is unified with the previous state and the mode is set
-according to  _N_.
-
-*/
-
-
-% if source_mode is on, then the source for the predicates
-% is stored with the code
-source_mode(Old,New) :-
-	'$access_yap_flags'(11,X),
-	'$transl_to_on_off'(X,Old),
-	'$transl_to_on_off'(XN,New),
-	'$set_yap_flags'(11,XN).
-
-/**   @pred source
-
-After executing this goal, YAP keeps information on the source
-of the predicates that will be consulted. This enables the use of
-[listing/0](@ref listing), `listing/1` and [clause/2](@ref clause) for those
-clauses.
-
-The same as `source_mode(_,on)` or as declaring all newly defined
-static procedures as `public`.
-*/
-source :- '$set_yap_flags'(11,1).
-
-
-/** @pred no_source
- The opposite to `source`.
-
-The same as `source_mode(_,off)`.
-
-*/
-no_source :- '$set_yap_flags'(11,0).
-
 /**
 @}
 */
diff --git a/pl/init.yap b/pl/init.yap
index 0a6cee7f9..36f9707a7 100644
--- a/pl/init.yap
+++ b/pl/init.yap
@@ -22,7 +22,6 @@
 
     @{
 */
-
 :- system_module( '$_init', [!/0,
         (:-)/1,
         (?-)/1,
@@ -109,17 +108,20 @@ otherwise.
 
 :- '$handle_throw'(_,_,_), !.
 
+:- $all_current_modules(M), yap_flag(M:unknown, error) ; true.
+
 :- bootstrap('errors.yap').
 :- bootstrap('lists.yap').
 :- bootstrap('consult.yap').
 :- bootstrap('preddecls.yap').
+:- bootstrap('preddyns.yap').
 
 
 :- bootstrap('atoms.yap').
 :- bootstrap('os.yap').
 :- bootstrap('absf.yap').
 
-:-'$swi_set_prolog_flag'(verbose,  normal).
+:-set_prolog_flag(verbose,  normal).
 
 :- [	 'directives.yap',
 	 'utils.yap',
@@ -127,7 +129,7 @@ otherwise.
 	 'arith.yap',
 	 'flags.yap'
    ].
-    
+
 :- [	 'preds.yap',
 	 'modules.yap'
    ].
@@ -185,6 +187,41 @@ version(yap,[6,3]).
 
 :- 	['undefined.yap'].
 
+:- multifile user:portray_message/2.
+
+:- dynamic user:portray_message/2.
+
+/** @pred  _CurrentModule_:goal_expansion(+ _G_,+ _M_,- _NG_), user:goal_expansion(+ _G_,+ _M_,- _NG_)
+
+
+YAP now supports goal_expansion/3. This is an user-defined
+procedure that is called after term expansion when compiling or
+asserting goals for each sub-goal in a clause. The first argument is
+bound to the goal and the second to the module under which the goal
+ _G_ will execute. If goal_expansion/3 succeeds the new
+sub-goal  _NG_ will replace  _G_ and will be processed in the same
+way. If goal_expansion/3 fails the system will use the default
+rules.
+
+
+*/
+:- multifile user:goal_expansion/3.
+
+:- dynamic user:goal_expansion/3.
+
+:- multifile user:goal_expansion/2.
+
+:- dynamic user:goal_expansion/2.
+
+:- multifile system:goal_expansion/2.
+
+:- dynamic system:goal_expansion/2.
+
+:- multifile goal_expansion/2.
+
+:- dynamic goal_expansion/2.
+
+
 :- use_module('messages.yap').
 :- use_module('hacks.yap').
 :- use_module('attributes.yap').
@@ -197,13 +234,11 @@ version(yap,[6,3]).
 :- use_module('../swi/library/menu.pl').
 :- use_module('../library/ypp.yap').
 
-
-
 yap_hacks:cut_by(CP) :- '$$cut_by'(CP).
 
 :- '$change_type_of_char'(36,7). % Make $ a symbol character
 
-:-	'$swi_set_prolog_flag'(generate_debug_info,true).
+:-	set_prolog_flag(generate_debug_info,true).
 
 
 :- recorda('$dialect',yap,_).
@@ -233,36 +268,6 @@ yap_hacks:cut_by(CP) :- '$$cut_by'(CP).
 
 :- module(user).
 
-/** @pred  _CurrentModule_:goal_expansion(+ _G_,+ _M_,- _NG_), user:goal_expansion(+ _G_,+ _M_,- _NG_)
-
-
-YAP now supports goal_expansion/3. This is an user-defined
-procedure that is called after term expansion when compiling or
-asserting goals for each sub-goal in a clause. The first argument is
-bound to the goal and the second to the module under which the goal
- _G_ will execute. If goal_expansion/3 succeeds the new
-sub-goal  _NG_ will replace  _G_ and will be processed in the same
-way. If goal_expansion/3 fails the system will use the default
-rules.
-
-
-*/
-:- multifile goal_expansion/3.
-
-:- dynamic goal_expansion/3.
-
-:- multifile goal_expansion/2.
-
-:- dynamic goal_expansion/2.
-
-:- multifile system:goal_expansion/2.
-
-:- dynamic system:goal_expansion/2.
-
-:- multifile goal_expansion/2.
-
-:- dynamic goal_expansion/2.
-
 
 /** @pred  _CurrentModule_:term_expansion( _T_,- _X_),  user:term_expansion( _T_,- _X_)
 
@@ -312,10 +317,6 @@ modules defining clauses for it too.
 
 :- dynamic user:message_hook/3.
 
-:- multifile user:portray_message/2.
-
-:- dynamic user:portray_message/2.
-
 /** @pred  exception(+ _Exception_, + _Context_, - _Action_)
 
 
@@ -338,12 +339,10 @@ If this hook predicate succeeds it must instantiate the  _Action_ argument to th
 
 :- dynamic user:exception/3.
 
-:- yap_flag(unknown,error).
+:- yap_flag(user:unknown,error).
 
 :- stream_property(user_input, tty(true)) -> set_prolog_flag(readline, true) ; true.
 
-
-
 /**
 @}
 */
diff --git a/pl/listing.yap b/pl/listing.yap
index 7591d5550..ec8b7a4f7 100644
--- a/pl/listing.yap
+++ b/pl/listing.yap
@@ -117,7 +117,7 @@ listing(Stream, [MV|MVs]) :- !,
    ).
 
 %
-% at this point we are ground and wew know who we want to list.
+% at this point we are ground and we know who we want to list.
 %
 '$listing'(Name, Arity, M, Stream) :-
 	% skip by default predicates starting with $
@@ -131,7 +131,7 @@ listing(Stream, [MV|MVs]) :- !,
 	'$do_error'(domain_error(predicate_spec,Name),listing(Name)).
 
 '$list_clauses'(Stream, M, Pred) :-
-	'$flags'(Pred,M,Flags,Flags),
+	'$predicate_flags'(Pred,M,Flags,Flags),
 	(Flags /\ 0x48602000 =\= 0
 	->
 	  nl(Stream),
@@ -192,7 +192,7 @@ listing(Stream, [MV|MVs]) :- !,
         nl( Stream ),
         fail.
 '$list_clauses'(Stream, M, Pred) :-
-    '$flags'(Pred,M,Flags,Flags),
+    '$predicate_flags'(Pred,M,Flags,Flags),
 	% has to be dynamic, source, or log update.
 	Flags /\ 0x08402000 =\= 0,
 	'$clause'(Pred, M, Body, _),