diff --git a/C/absmi.c b/C/absmi.c
index 1a2ff7192..1eafdece3 100644
--- a/C/absmi.c
+++ b/C/absmi.c
@@ -1277,8 +1277,37 @@ absmi(int inp)
 	    case _retry_profiled:
 	      opnum = op_from_opcode(NEXTOP(B->cp_ap,l)->opc);
 	      goto restart_cp;
-	    default:
+	    case _retry_me:
+	    case _trust_me:
+	    case _profiled_retry_me:
+	    case _profiled_trust_me:
+	    case _retry_me0:
+	    case _trust_me0:
+	    case _retry_me1:
+	    case _trust_me1:
+	    case _retry_me2:
+	    case _trust_me2:
+	    case _retry_me3:
+	    case _trust_me3:
+	    case _retry_me4:
+	    case _trust_me4:
+	    case _retry_and_mark:
+	    case _profiled_retry_and_mark:
+	    case _retry:
+	    case _trust_in:
+	    case _trust:
+	    case _retry_first:
+	    case _trust_first_in:
+	    case _trust_first:
+	    case _retry_tail:
+	    case _trust_tail_in:
+	    case _trust_tail:
+	    case _retry_head:
+	    case _trust_head_in:
+	    case _trust_head:
 	      low_level_trace(retry_pred, (PredEntry *)(PREG->u.ld.p), &(B->cp_a1));
+	    default:
+	      break;
 	    }
 	  }
 #endif	/* LOW_LEVEL_TRACER */
diff --git a/C/arith0.c b/C/arith0.c
index d4dda1664..971bb456b 100644
--- a/C/arith0.c
+++ b/C/arith0.c
@@ -149,7 +149,17 @@ p_env(E_ARGS)
 #if SBA
   RINT((Int)YENV);
 #else
-  RINT(YENV - (CELL *)B);
+  RINT(LCL0 - YENV);
+#endif
+}
+
+static E_FUNC
+p_tr(E_ARGS)
+{
+#if SBA
+  RINT(TR);
+#else
+  RINT(((CELL *)TR)-LCL0);
 #endif
 }
 
@@ -189,6 +199,7 @@ static InitConstEntry InitConstTab[] = {
   {"global_sp", p_globalsp},
   {"$last_choice_pt", p_b},
   {"$env", p_env},
+  {"$tr", p_tr},
   {"stackfree", p_stackfree},
 };
 
diff --git a/C/arrays.c b/C/arrays.c
index 8e7f7ef66..6c670cfab 100644
--- a/C/arrays.c
+++ b/C/arrays.c
@@ -1572,60 +1572,6 @@ p_sync_mmapped_arrays(void)
   return(TRUE);
 }
 
-/*
-  This is a hack, to steal the first element of a key.
-
-   It first fetches the first element in the chain, and then erases it
-   through its reference.
-
-  Be careful when using this routine. It is especially evil because if
-  the term is ground it should be copied to the stack, as space for
-  the entry may be deleted. For the moment, the terms I want are just
-  integers, so no problemo, amigo.
-
- */
-static Term
-StealFirstFromDB(DBRef ref)
-{
-  Term TermDB, out;
-
-  if ((TermDB = FetchTermFromDB(ref,3)) == (CELL)0) {
-    /* oops, we are in trouble, not enough stack space */
-    return(TermNil);
-  }
-  if (IsVarTerm(TermDB) || !IsApplTerm(TermDB))
-    /* it's not a wonderful world afterall */
-    return(TermNil);
-  out = ArgOfTerm(1,TermDB);
-  /* now, return what once was there, only nevermore */
-  return(out);
-}
-
-Int
-SetDBForThrow(Term Message)
-{
-  Term cut_pt_term;
-  Atom a = FullLookupAtom("$catch_queue");
-  AtomEntry *ae = RepAtom(a);
-  StaticArrayEntry *ptr;
-  DBRef ref;
-  READ_LOCK(ae->ARWLock);
-  ptr =  RepStaticArrayProp(ae->PropsOfAE);    
-  while (!EndOfPAEntr(ptr) && ptr->KindOfPE != ArrayProperty)
-    ptr = RepStaticArrayProp(ptr->NextOfPE);
-  READ_UNLOCK(ae->ARWLock);
-  ref = ptr->ValueOfVE.terms[0];
-
-  cut_pt_term = StealFirstFromDB(ref);
-  if (IsVarTerm(cut_pt_term) || !IsIntegerTerm(cut_pt_term)) {
-    /* ooops, babe we are in trouble */
-    return(-1);
-  }
-  /* OK, we've got the place to cut to, next store the new throw */
-  ptr->ValueOfVE.terms[1] = StoreTermInDB(Message,3);
-  return(IntegerOfTerm(cut_pt_term));  
-}
-
 void 
 InitArrayPreds(void)
 {
diff --git a/C/errors.c b/C/errors.c
index 6b963c539..b78428fdb 100644
--- a/C/errors.c
+++ b/C/errors.c
@@ -207,74 +207,6 @@ exit_yap (int value, char *msg)
   exit(value);
 }
 
-void
-Abort (char *format,...)
-{
-  va_list ap;
-  va_start (ap, format);
-
-  PrologMode &= ~AbortMode;
-  if (format || !strcmp(format,""))
-    {
-      char ch;
-      while ((ch = *format++)!=0)
-	if (ch != '%')
-	  YP_putc (ch, YP_stderr);
-	else
-	  {
-	    switch (*format++)
-	      {
-	      case 'c':
-		YP_putc (va_arg (ap, int), YP_stderr);
-		break;
-	      case 's':
-		YP_fprintf(YP_stderr, "%s", va_arg (ap, char *));
-		break;
-	      case 'd':
-#if SHORT_INTS
-		YP_fprintf(YP_stderr, "%ld", va_arg (ap, Int));
-#else
-		YP_fprintf(YP_stderr, "%d", va_arg (ap, Int));
-#endif
-		break;
-	      case 'x':
-#if SHORT_INTS
-		YP_fprintf(YP_stderr, "%lx", va_arg (ap, Int));
-#else
-		YP_fprintf(YP_stderr, "%x", va_arg (ap, Int));
-#endif
-		break;
-	      }
-	  }
-      YP_putc ('\n', YP_stderr);
-    }
-  va_end (ap);
-#ifdef DEBUGX
-  DumpActiveGoals();
-#endif /* DEBUG */
-  if (PrologMode & BootMode) {
-    exit_yap (1, NIL);
-  } else {
-    PutValue(AtomThrow, MkAtomTerm(AtomFalse));
-    CreepFlag = CalculateStackGap();
-#if PUSH_REGS
-    restore_absmi_regs(&standard_regs);
-#endif
-#if defined(__GNUC__)
-#if (defined(hppa) || defined(__alpha))
-    /* siglongjmp resets the TR hardware register */
-    save_TR();
-#endif
-#if defined(__alpha)
-    /* siglongjmp resets the H hardware register */
-    save_H();
-#endif
-#endif
-    siglongjmp (RestartEnv, 1);
-  }
-}
-
-
 static void detect_bug_location(char *tp, int psize)
 {
   Atom pred_name;
@@ -1806,34 +1738,24 @@ Error (yap_error_number type, Term where, char *format,...)
   }
   nt[1] = MkAtomTerm(LookupAtom(p));
   if (serious) {
-    Int depth;
-
+    choiceptr newb;
+    PredEntry *p = RepPredProp(PredPropByFunc(FunctorThrow,0));
+      
     CreepFlag = CalculateStackGap();
+    ASP--;
+    newb = ((choiceptr)ASP)-1;
+    newb->cp_h     = H;
+    newb->cp_tr    = TR;
+    newb->cp_cp    = CP;
+    newb->cp_ap    = (yamop *)(p->CodeOfPred);
+    newb->cp_env   = ENV;
+    newb->cp_b     = B;
     if (type == PURE_ABORT)
-      depth = SetDBForThrow(MkAtomTerm(LookupAtom("abort")));
+      ARG1 = newb->cp_a1 = MkAtomTerm(LookupAtom("abort"));
     else
-      depth = SetDBForThrow(MkApplTerm(fun, 2, nt));
-    if (depth == -1) {
-      /* if we did not find an error already */
-      if (P != (yamop *)FAILCODE)
-	/* oops, we lost our trap handler, backtrack until the root or
-           until an instance of do_goal */
-	while (B->cp_b != NULL && B->cp_ap != (yamop *) NOCODE)
-	  B = B->cp_b;
-      P = (yamop *)FAILCODE;
-      PrologMode &= ~InErrorMode;
-      return(P);
-    }
-    /* make the abstract machine jump where we want them to jump to */
-#ifdef YAPOR
-#if SBA
-    CUT_prune_to((choiceptr)depth);
-#else
-    CUT_prune_to((choiceptr)(LCL0-depth));
-#endif
-#else
-    B = (choiceptr)(LCL0-depth);
-#endif	/* YAPOR */
+      ARG1 = newb->cp_a1 = MkApplTerm(fun, 2, nt);
+    B = newb;
+    ASP = YENV = (CELL *)B;
     P = (yamop *)FAILCODE;
   }
   PrologMode &= ~InErrorMode;
diff --git a/C/exec.c b/C/exec.c
index a14369c95..203f3eb33 100644
--- a/C/exec.c
+++ b/C/exec.c
@@ -833,7 +833,6 @@ exec_absmi(int top)
   int lval;
   if (top && (lval = sigsetjmp (RestartEnv, 1)) != 0) {
     if (lval == 1) { /* restart */
-      int depth;
       /* otherwise, SetDBForThrow will fail entering critical mode */
       PrologMode = UserMode;
       /* find out where to cut to */
@@ -846,17 +845,6 @@ exec_absmi(int top)
      /* siglongjmp resets the H hardware register */
       restore_H();
 #endif
-#endif
-      depth = SetDBForThrow(MkAtomTerm(LookupAtom("abort")));
-      if (depth == 0) {
-	Error(SYSTEM_ERROR, TermNil, "database entry for throw corrupted");
-      }
-      /* make the abstract machine jump where we want them to jump to */
-
-#ifdef SBA
-      B = (choiceptr)depth;
-#else
-      B = (choiceptr)(LCL0-depth);
 #endif
       yap_flags[SPY_CREEP_FLAG] = 0;
       CreepFlag = CalculateStackGap();
@@ -1262,20 +1250,38 @@ p_clean_ifcp(void) {
   return(TRUE);
 }
 
+/* This does very nasty stuff!!!!! */
 static Int
 p_jump_env(void) {
   CELL *env = LCL0-IntegerOfTerm(Deref(ARG1)), *prev = NULL, *cur = ENV;
+  choiceptr old, cptr, ocptr;
 
   while (cur != env) {
     prev = cur;
     cur = (CELL *)cur[E_E];
   }
-  ENV[E_CP] = prev[E_CP];
-  ENV[E_E] = prev[E_E];
-  return(TRUE);
+  if (prev != NULL) {
+    CP = (yamop *)(prev[E_CP]);
+  }
+  ENV = env;
+  /* force trail reset */
+  old = (choiceptr)(env[E_CB]);
+  cptr = ocptr = B;
+  while (ocptr->cp_b < old) {
+    ocptr = ocptr->cp_b;
+  }
+  while (cptr != ocptr) {
+    cptr->cp_tr = ocptr->cp_tr;
+    cptr = cptr->cp_b;
+  }
+  /* I could do this, but it is easier to leave the undwindig to the emulator */
+  B->cp_env = env;
+  B->cp_cp = CP;
+  B->cp_h = H;
+  env[CP->u.yx.y] = ARG2;
+  return(FALSE);
 }
 
-
 void 
 InitExecFs(void)
 {
@@ -1305,6 +1311,6 @@ InitExecFs(void)
   InitCPred("$restore_regs", 1, p_restore_regs, SafePredFlag);
   InitCPred("$restore_regs", 2, p_restore_regs2, SafePredFlag);
   InitCPred("$clean_ifcp", 1, p_clean_ifcp, SafePredFlag);
-  InitCPred("$jump_env", 1, p_jump_env, SafePredFlag);
+  InitCPred("$jump_env_and_store_ball", 2, p_jump_env, SafePredFlag);
 }
 
diff --git a/C/init.c b/C/init.c
index fac1ad66f..a2e0b96e4 100644
--- a/C/init.c
+++ b/C/init.c
@@ -929,7 +929,6 @@ InitCodes(void)
   heap_regs->atom_stack_free = LookupAtom("stackfree");
   AtomStream = LookupAtom ("$stream");
   AtomStreamPos = LookupAtom ("$stream_position");
-  heap_regs->atom_throw = LookupAtom("$throw");
   heap_regs->atom_true = LookupAtom("true");
   AtomSpy = LookupAtom("$spy");
   heap_regs->atom_user = LookupAtom ("user");
@@ -987,6 +986,7 @@ InitCodes(void)
   heap_regs->functor_stream_eOS = MkFunctor (LookupAtom("end_of_stream"), 1);
   heap_regs->functor_change_module = MkFunctor (LookupAtom("$change_module"), 1);
   heap_regs->functor_current_module = MkFunctor (LookupAtom("$current_module"), 1);
+  heap_regs->functor_throw = MkFunctor( LookupAtom("throw"), 1);
   heap_regs->functor_u_minus = MkFunctor (heap_regs->atom_minus, 1);
   heap_regs->functor_u_plus = MkFunctor (heap_regs->atom_plus, 1);
   heap_regs->functor_v_bar = MkFunctor(LookupAtom("|"), 2);
diff --git a/C/iopreds.c b/C/iopreds.c
index 3f4019112..fd13be29f 100644
--- a/C/iopreds.c
+++ b/C/iopreds.c
@@ -4781,7 +4781,7 @@ p_stream(void)
 void
 InitBackIO (void)
 {
-  InitCPredBack ("current_stream", 3, 1, init_cur_s, cont_cur_s, SafePredFlag|SyncPredFlag);
+  InitCPredBack ("$current_stream", 3, 1, init_cur_s, cont_cur_s, SafePredFlag|SyncPredFlag);
 }
 
 void
diff --git a/C/save.c b/C/save.c
index 1affa95d1..a84845c05 100644
--- a/C/save.c
+++ b/C/save.c
@@ -1051,7 +1051,6 @@ restore_codes(void)
   heap_regs->atom_repeat = AtomAdjust(heap_regs->atom_repeat);
   heap_regs->atom_restore_regs = AtomAdjust(heap_regs->atom_restore_regs);
   heap_regs->atom_stack_free = AtomAdjust(heap_regs->atom_stack_free);
-  heap_regs->atom_throw = AtomAdjust(heap_regs->atom_throw);
   heap_regs->atom_true = AtomAdjust(heap_regs->atom_true);
   heap_regs->atom_user = AtomAdjust(heap_regs->atom_user);
   heap_regs->atom_usr_err = AtomAdjust(heap_regs->atom_usr_err);
@@ -1102,6 +1101,7 @@ restore_codes(void)
   heap_regs->functor_stream_eOS = FuncAdjust(heap_regs->functor_stream_eOS);
   heap_regs->functor_change_module = FuncAdjust(heap_regs->functor_change_module);
   heap_regs->functor_current_module = FuncAdjust(heap_regs->functor_current_module);
+  heap_regs->functor_throw = FuncAdjust(heap_regs->functor_throw);
   heap_regs->functor_u_minus = FuncAdjust(heap_regs->functor_u_minus);
   heap_regs->functor_u_plus = FuncAdjust(heap_regs->functor_u_plus);
   heap_regs->functor_v_bar = FuncAdjust(heap_regs->functor_v_bar);
diff --git a/C/stdpreds.c b/C/stdpreds.c
index ad12627bc..715c8eb30 100644
--- a/C/stdpreds.c
+++ b/C/stdpreds.c
@@ -1230,9 +1230,7 @@ static Int
 p_abort(void)
 {				/* abort			 */
   /* make sure we won't go creeping around */
-  CreepFlag = CalculateStackGap();
-  yap_flags[SPY_CREEP_FLAG] = 0;
-  Abort("");
+  Error(PURE_ABORT, TermNil, "");
   return(FALSE);
 }
 
diff --git a/H/Heap.h b/H/Heap.h
index bed864456..365032160 100644
--- a/H/Heap.h
+++ b/H/Heap.h
@@ -10,7 +10,7 @@
 * File:		Heap.h         						 *
 * mods:									 *
 * comments:	Heap Init Structure					 *
-* version:      $Id: Heap.h,v 1.16 2002-01-01 05:26:25 vsc Exp $	 *
+* version:      $Id: Heap.h,v 1.17 2002-01-07 06:28:03 vsc Exp $	 *
 *************************************************************************/
 
 /* information that can be stored in Code Space */
@@ -197,7 +197,6 @@ typedef struct various_codes {
     atom_repeat,
     atom_restore_regs,
     atom_stack_free,
-    atom_throw,
     atom_true,
     atom_unwritable,
     atom_user,
@@ -254,6 +253,7 @@ typedef struct various_codes {
     functor_stream_eOS,
     functor_change_module,
     functor_current_module,
+    functor_throw,
     functor_u_minus,
     functor_u_plus,
     functor_v_bar,
@@ -388,7 +388,6 @@ typedef struct various_codes {
 #define  AtomRepeat               heap_regs->atom_repeat
 #define  AtomRestoreRegs          heap_regs->atom_restore_regs
 #define  AtomStackFree            heap_regs->atom_stack_free
-#define  AtomThrow                heap_regs->atom_throw
 #define  AtomTrue                 heap_regs->atom_true
 #define  AtomUser                 heap_regs->atom_user
 #define  AtomUsrErr               heap_regs->atom_usr_err
@@ -444,6 +443,7 @@ typedef struct various_codes {
 #define  FunctorChangeModule      heap_regs->functor_change_module
 #define  FunctorCurrentModule     heap_regs->functor_current_module
 #define  FunctorModSwitch         heap_regs->functor_mod_switch
+#define  FunctorThrow             heap_regs->functor_throw
 #define  FunctorUMinus            heap_regs->functor_u_minus
 #define  FunctorUPlus             heap_regs->functor_u_plus
 #define  FunctorVBar              heap_regs->functor_v_bar
diff --git a/H/Yapproto.h b/H/Yapproto.h
index b06696aac..5be335a7c 100644
--- a/H/Yapproto.h
+++ b/H/Yapproto.h
@@ -10,7 +10,7 @@
 * File:		Yap.proto						 *
 * mods:									 *
 * comments:	Function declarations for YAP				 *
-* version:      $Id: Yapproto.h,v 1.6 2002-01-02 20:56:22 vsc Exp $	 *
+* version:      $Id: Yapproto.h,v 1.7 2002-01-07 06:28:03 vsc Exp $	 *
 *************************************************************************/
 
 /* prototype file for Yap */
@@ -133,7 +133,6 @@ void	STD_PROTO(WakeUp,(CELL *));
 /* dbase.c */
 int     STD_PROTO(DBTrailOverflow,(void));
 CELL	STD_PROTO(EvalMasks,(Term,CELL *));
-Int	STD_PROTO(SetDBForThrow,(Term));
 void	STD_PROTO(InitBackDB,(void));
 void	STD_PROTO(InitDBPreds,(void));
 
@@ -276,7 +275,6 @@ void	STD_PROTO(InitUtilCPreds,(void));
 
 /* yap.c */
 
-void	STD_PROTO(Abort,(char *msg, ...));
 void	STD_PROTO(addclause,(Term,CODEADDR,int,int));
 
 /* ypsocks.c */
diff --git a/pl/boot.yap b/pl/boot.yap
index c263550d5..00aec237c 100644
--- a/pl/boot.yap
+++ b/pl/boot.yap
@@ -30,7 +30,7 @@ true :- true. % otherwise, $$compile will ignore this clause.
 		;
 		    '$format'(user_error,"[~w]~n", [Module])
 		),
-		'$system_catch'('$enter_top_level',Error,user:'$Error'(Error)).
+		'$system_catch'('$enter_top_level',Module,Error,user:'$Error'(Error)).
 
 
 '$init_system' :-
@@ -43,7 +43,6 @@ true :- true. % otherwise, $$compile will ignore this clause.
 	'$set_yap_flags'(10,0),
 	'$set_value'('$gc',on),
 	'$init_catch',
-%	'$init_newcatch',  commented out for now
 	prompt('  ?- '),
 	(
 	    '$get_value'('$break',0)
@@ -61,7 +60,6 @@ true :- true. % otherwise, $$compile will ignore this clause.
 		( exists('~/.prologrc') -> [-'~/.prologrc'] ; true ),
 		( exists('~/prolog.ini') -> [-'~/prolog.ini'] ; true )
 	    ),
-	    '$clean_catch_and_throw',
 	    '$db_clean_queues'(0),
 	    '$startup_reconsult',
 	    '$startup_goals'
@@ -103,7 +101,7 @@ true :- true. % otherwise, $$compile will ignore this clause.
 	'$recorded'('$restore_goal',G,R),
 	erase(R),
 	prompt(_,'   | '),
-	'$system_catch'('$do_yes_no'((G->true),user),Error,user:'$Error'(Error)),
+	'$system_catch'('$do_yes_no'((G->true),user),user,Error,user:'$Error'(Error)),
 	fail.
 '$enter_top_level' :-
 	( '$get_value'('$trace', 1) ->
@@ -138,7 +136,8 @@ true :- true. % otherwise, $$compile will ignore this clause.
 
 '$startup_goals' :-
 	'$recorded'('$startup_goal',G,_),
-	'$system_catch'('$query'((G->true), []),Error,user:'$Error'(Error)),
+	'$current_module'(Module),
+	'$system_catch'('$query'((G->true), []),Module,Error,user:'$Error'(Error)),
 	fail.
 '$startup_goals'.
 
@@ -885,20 +884,20 @@ break :- '$get_value'('$break',BL), NBL is BL+1,
 	'$get_value'('$consulting_file',OldF),
 	'$set_consulting_file'(Stream),
 	H0 is heapused, T0 is cputime,
-	current_stream(File,_,Stream),
+	'$current_stream'(File,_,Stream),
 	'$start_consult'(consult,File,LC),
 	'$get_value'('$consulting',Old),
 	'$set_value'('$consulting',true),
 	'$recorda'('$initialisation','$',_),
 	( '$get_value'('$verbose',on) ->
-		tab(user_error,LC),
+		'$tab'(user_error,LC),
 		'$format'(user_error, "[ consulting ~w... ]~n", [F])
 	    ; true ),
 	'$loop'(Stream,consult),
 	'$end_consult',
 	( LC == 0 -> prompt(_,'   |: ') ; true),
 	( '$get_value'('$verbose',on) ->
-		tab(user_error,LC) ;
+		'$tab'(user_error,LC) ;
 	true ),
 	H is heapused-H0, T is cputime-T0,
 	( '$get_value'('$verbose',off) ->
@@ -954,11 +953,11 @@ break :- '$get_value'('$break',BL), NBL is BL+1,
 	'$current_module'(OldModule),
 	'$change_alias_to_stream'('$loop_stream',Stream),
 	repeat,
-		( current_stream(_,_,Stream) -> true
+		( '$current_stream'(_,_,Stream) -> true
 		 ; '$current_module'(_,OldModule), '$abort_loop'(Stream)
 		),
 		prompt('|     '), prompt(_,'| '),
-		'$system_catch'('$enter_command'(Stream,Status), Error,
+		'$system_catch'('$enter_command'(Stream,Status), OldModule, Error,
 			 user:'$LoopError'(Error)),
 	!,
 	'$exec_initialisation_goals',
@@ -1119,96 +1118,29 @@ expand_term(Term,Expanded) :-
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %   catch/throw implementation
 
-/* new design, not working for now:
+/* new design, not working for now: */
 
 % at each catch point I need to know:
 % what is ball;
 % where was the previous catch	
-newcatch(G, C, A) :-
+catch(G, C, A) :-
+	'$mark_tr'(Ball),
 	array_element('$catch', 0, OldEnv),
 	Env is '$env',
 	update_array('$catch', 0, Env),
 	'$execute'(G),
-	update_array('$catch', 0, Env),
-	array_element('$catch', 1, V),
-	(var(V) ->
-	    true
+	'$force_to_1st'(Ball),
+	( var(Ball) ->
+	    % no throw, just get rid of this.
+	    update_array('$catch', 0, OldEnv)
 	;
-	    !, '$handle_throw'(C, A)
+	    % jmp_env will reset both fields  for me!
+	    !, '$handle_throw'(C, A, Ball)
 	).
 
-'$handle_throw'(C, A) :-
-        % reset info 
-	array_element('$catch', 1, _),
-	array_element('$catch', 2, Ball),
-	(C = Ball ->
-	    '$execute'(A)
-	    ;
-	    throw(Ball)
-	).
-
-newthrow(Ball) :-
-	% say we are throwing something.
-	array_element('$catch', 1, []),
-	update_array('$catch', 2, Ball),
-	array_element('$catch', 0, Env),
-	'$jump_env'(Env).
-
-'$init_newcatch' :-
-	'$create_array'('$catch', 3).
-
-
-*/
-	
-catch(G,C,A) :- var(G), !,
-	throw(error(instantiation_error,catch(G,C,A))).
-catch(G,C,A) :- number(G), !,
-	throw(error(type_error(callable,G),catch(G,C,A))).
-catch(R,C,A) :- db_reference(R), !,
-	throw(error(type_error(callable,R),catch(R,C,A))).
-catch(G,C,A) :-
-	'$catch'(G,C,A).
-
-'$catch'(G,C,A) :-
-	'$get_value'('$catch', I),
-	I1 is I+1,
-	'$set_value'('$catch', I1),
-	'$current_module'(M),
-	'$catch'(G,C,A,I,M).
-
-'$catch'(G,_,_,I,_) :-
-        % on entry we push the catch choice point
-        X is '$last_choice_pt',
-	'$catch_call'(X,G,I, NX),
-	(X = NX -> !, '$erase_catch_elements'(I) ; true).
-% someone sent us a throw.
-'$catch'(_,C,A,_,M) :-
-	array_element('$catch_queue', 1, X), X \= '$',
-	update_array('$catch_queue', 1, '$'),
-	array_element('$catch_queue', 0, catch(_,Lev,Q)), !,
-	update_array('$catch_queue', 0, Q),
-	'$db_clean_queues'(Lev),
-        '$erase_catch_elements'(Lev),
-        ( C=X -> '$current_module'(_,M), '$execute'(A) ; throw(X)).
-% normal exit: make sure we only erase what we should erase!
-'$catch'(_,_,_,I,_) :-
-        '$erase_catch_elements'(I),
-	fail.
-
-'$catch_call'(X,G,I,NX) :-
-	array_element('$catch_queue', 0, OldCatch),
-	update_array('$catch_queue', 0, catch(X,I,OldCatch)),
-        '$execute'(G),
-	NX is '$last_choice_pt',
-        (
-	  array_element('$catch_queue', 0, catch(X,I,Catch)),
-	  update_array('$catch_queue', 0, Catch)
-	;
-          % on backtracking reinstate the catch before backtracking to G
-	  array_element('$catch_queue', 0, Catch),
-	  update_array('$catch_queue', 0, catch(X,I,Catch)),
-          fail
-        ).
+% just create a choice-point
+'$mark_tr'(_).
+'$mark_tr'(_) :- fail.
 
 %
 % system_catch is like catch, but it avoids the overhead of a full
@@ -1216,104 +1148,47 @@ catch(G,C,A) :-
 % This way it
 % also avoids module preprocessing and goal_expansion
 %
-'$system_catch'(G,C,A) :-
-	'$get_value'('$catch', I),
-	I1 is I+1,
-	'$set_value'('$catch', I1),
-	'$current_module'(M),
-	'$system_catch'(G,C,A,I,M).
-
-'$system_catch'(G,_,_,I,_) :-
-        % on entry we push the catch choice point
-        X is '$last_choice_pt',
-	'$system_catch_call'(X,G,I,NX),
-	( X = NX -> !, '$erase_catch_elements'(I) ; true).
-% someone sent us a throw.
-'$system_catch'(_,C,A,_,M) :-
-	array_element('$catch_queue', 1, X), X \= '$',
-	update_array('$catch_queue', 1, '$'),
-	array_element('$catch_queue', 0, catch(_,Lev,Q)), !,
-	update_array('$catch_queue', 0, Q),
-	'$db_clean_queues'(Lev),
-        '$erase_catch_elements'(Lev),
-        ( C=X ->
-	    '$execute'(M:A)
+'$system_catch'(G, M, C, A) :-
+	% check current trail
+	'$mark_tr'(Ball),
+	% update current catch handler
+	array_element('$catch', 0, OldEnv),
+	Env is '$env',
+	update_array('$catch', 0, Env),
+	'$execute0'(G, M),
+	% this says where Ball is, for the benefit of jump_env
+	'$force_to_1st'(Ball),
+	(
+	  var(Ball) ->
+	    % no throw, just get rid of this.
+	    update_array('$catch', 0, OldEnv)
 	;
-	  throw(X)
-        ).
-% normal exit: make sure we only erase what we should erase!
-'$system_catch'(_,_,_,I,_) :-
-        '$erase_catch_elements'(I),
-	fail.
+	    % process the throw, if we can.
+	    !, '$handle_throw'(C, A, Ball)
+	).
 
-'$erase_catch_elements'(I) :-
-	array_element('$catch_queue', 0, OldCatch),
-	'$erase_catch_elements'(OldCatch, I, Catch),
-	update_array('$catch_queue', 0, Catch).
+'$force_to_1st'(_).
 
-'$erase_catch_elements'(catch(_, J, P), I, Catch) :-
-          J >= I, !,
-	  '$erase_catch_elements'(P, I, Catch).
-'$erase_catch_elements'(Catch, _, Catch).
-	  
-'$system_catch_call'(X,G,I, NX) :-
-	array_element('$catch_queue', 0, OldCatch),
-	update_array('$catch_queue', 0, catch(X,I,OldCatch)),
-	'$current_module'(M),
-        '$execute0'(G,M),
-	NX is '$last_choice_pt',
-        ( % on exit remove the catch
-	  array_element('$catch_queue', 0, catch(X,I,Catch)),
-	  update_array('$catch_queue', 0, Catch)
-        ;
-          % on backtracking reinstate the catch before backtracking to G
-	  array_element('$catch_queue', 0, Catch),
-	  update_array('$catch_queue', 0, catch(X,I,Catch)),
-          fail
-        ).
-
-throw(A) :-
-	% fetch the point to jump to
-	array_element('$catch_queue', 0, catch(X,_,_)), !,
-	% now explain why we are jumping.
-	update_array('$catch_queue', 1, A),
-        '$$cut_by'(X),
-        fail.
-throw(G) :-
-        '$format'(user_error,"system_error_at(~w)",[G]),
-        abort.
+'$handle_throw'(C, A, '$ball'(Ball)) :-
+        % reset info 
+	(C = Ball ->
+	    '$execute'(A)
+	    ;
+	    throw(Ball)
+	).
 
+throw(Ball) :-
+	% get this off the unwound computation.
+	copy_term(Ball,NewBall),
+	% get current jump point
+	array_element('$catch', 0, Env),
+	% jump
+	'$jump_env_and_store_ball'(Env, '$ball'(NewBall)).
+% restore bindings.
+throw(_).
 
 '$init_catch' :-
-	% initialise access to the catch queue
-	( '$has_static_array'('$catch_queue') ->
-	    true
-	;
-	    static_array('$catch_queue',2, term)
-	),
-	update_array('$catch_queue', 0, '$'),
-	update_array('$catch_queue', 1, '$').
-
-
-'$check_list'(V, _) :- var(V), !.
-'$check_list'([], _) :- !.
-'$check_list'([_|B], T) :- !,
-	'$check_list'(B,T).
-'$check_list'(S, T) :-
-	throw(error(type_error(list,S),T)).
-
-'$clean_catch_and_throw' :-
-	'$set_value'('$catch', 0),
-	fail.
-'$clean_catch_and_throw' :-
-	'$recorded'('$catch',_,R),
-	erase(R),
-	fail.
-'$clean_catch_and_throw' :-
-	'$recorded'('$throw',_,R),
-	erase(R),
-	fail.
-'$clean_catch_and_throw'.
+	'$create_array'('$catch', 1).
 
 '$exec_initialisation_goals' :-
 	'$recorded'('$blocking_code',_,R),
@@ -1330,7 +1205,8 @@ throw(G) :-
 	'$recorded'('$initialisation',G,R),
 	erase(R),
 	G \= '$',
-	'$system_catch'(once(G), Error, user:'$LoopError'(Error)),
+	'$current_module'(M),
+	'$system_catch'(once(M:G), M, Error, user:'$LoopError'(Error)),
 	fail.
 '$exec_initialisation_goals'.
 
@@ -1342,4 +1218,3 @@ throw(G) :-
 '$run_toplevel_hooks'.
 
 
-
diff --git a/pl/consult.yap b/pl/consult.yap
index 97df9c751..6eb95acc8 100644
--- a/pl/consult.yap
+++ b/pl/consult.yap
@@ -31,7 +31,7 @@ ensure_loaded(V) :-
         '$change_module'(M0).
 '$ensure_loaded'(X) :- atom(X), !,
 	'$find_in_path'(X,Y),
-	( open(Y,'$csult',Stream), !,
+	( '$open'(Y, '$csult', Stream, 0), !,
 	     ( '$loaded'(Stream) ->
 		(  '$consulting_file_name'(Stream,TFN),
 		    '$recorded'('$module','$module'(TFN,M,P),_) ->
@@ -43,14 +43,14 @@ ensure_loaded(V) :-
 	       '$record_loaded'(Stream),
 	       '$reconsult'(X,Stream)
 	     ),
-	      close(Stream)
+	     '$close'(Stream)
 	;
 		
 	throw(error(permission_error(input,stream,X),ensure_loaded(X)))
 	).
 '$ensure_loaded'(library(X)) :- !,
 	'$find_in_path'(library(X),Y),
-	( open(Y,'$csult',Stream), !,
+	( '$open'(Y,'$csult',Stream, 0), !,
 	     ( '$loaded'(Stream) ->
 		(  '$consulting_file_name'(Stream,TFN),
 		    '$recorded'('$module','$module'(TFN,M,P),_) ->
@@ -62,7 +62,7 @@ ensure_loaded(V) :-
 	       '$record_loaded'(Stream),
 	       '$reconsult'(Y,Stream)
 	     ),
-	      close(Stream)
+	     '$close'(Stream)
 	;
 	throw(error(permission_error(input,stream,library(X)),ensure_loaded(library(X))))
 	).
@@ -107,17 +107,17 @@ reconsult(Fs) :-
 	'$reconsult'(Fs).
 '$reconsult'(X) :- atom(X), !,
 	'$find_in_path'(X,Y),
-	( open(Y,'$csult',Stream), !,
+	( '$open'(Y,'$csult',Stream,0), !,
 		'$record_loaded'(Stream),
-		'$reconsult'(X,Stream), close(Stream)
+		'$reconsult'(X,Stream), '$close'(Stream)
 	;
 		throw(error(permission_error(input,stream,X),reconsult(X)))
 	).
 '$reconsult'(library(X)) :- !,
 	'$find_in_path'(library(X),Y),
-	( open(Y,'$csult',Stream), !,
+	( '$open'(Y,'$csult',Stream,0), !,
 		'$record_loaded'(Stream),
-		'$reconsult'(library(X),Stream), close(Stream)
+		'$reconsult'(library(X),Stream), '$close'(Stream)
 	;
 		throw(error(permission_error(input,stream,library(X)),reconsult(library(X))))
 	).
@@ -136,7 +136,7 @@ reconsult(Fs) :-
 	'$start_consult'(reconsult,File,LC),
 	'$recorda'('$initialisation','$',_),
 	( '$get_value'('$verbose',on) ->
-		tab(user_error,LC),
+		'$tab'(user_error,LC),
 		'$format'(user_error, "[ reconsulting ~w... ]~n", [F])
 	    ; true ),
 	'$loop'(Stream,reconsult),
@@ -144,7 +144,7 @@ reconsult(Fs) :-
 	'$clear_reconsulting',
 	( LC == 0 -> prompt(_,'   |: ') ; true),
 	( '$get_value'('$verbose',on) ->
-		tab(user_error,LC) ;
+		'$tab'(user_error,LC) ;
 	true ),	
 	H is heapused-H0, T is cputime-T0,
 	( '$get_value'('$verbose',off) ->
@@ -162,11 +162,11 @@ reconsult(Fs) :-
 	'$recorda'('$reconsulting',F,_).
 
 'EMACS_FILE'(F,File0) :-
-	format('''EMACS_RECONSULT''(~w).~n',[File0]),
+	'$format'('''EMACS_RECONSULT''(~w).~n',[File0]),
 	'$getcwd'(OldD),
-	open(F,'$csult',Stream),
+	'$open'(F,'$csult',Stream,0),
 	'$find_in_path'(File0,File),
-	open(File,'$csult',Stream0),
+	'$open'(File,'$csult',Stream0,0),
 	'$get_value'('$consulting_file',OldF),
 	'$set_consulting_file'(Stream0),
 	H0 is heapused, T0 is cputime,
@@ -176,7 +176,7 @@ reconsult(Fs) :-
 	'$start_consult'(reconsult,File,LC),
 	'$recorda'('$initialisation','$',_),
 	( '$get_value'('$verbose',on) ->
-		tab(user_error,LC),
+		'$tab'(user_error,LC),
 		'$format'(user_error, "[ reconsulting ~w... ]~n", [F])
 	    ; true ),
 	'$loop'(Stream,reconsult),
@@ -184,7 +184,7 @@ reconsult(Fs) :-
 	'$clear_reconsulting',
 	( LC == 0 -> prompt(_,'   |: ') ; true),
 	( '$get_value'('$verbose',on) ->
-		tab(user_error,LC) ;
+		'$tab'(user_error,LC) ;
 	true ),	
 	H is heapused-H0, T is cputime-T0,
 	( '$get_value'('$verbose',off) ->
@@ -220,8 +220,8 @@ reconsult(Fs) :-
 '$include'(X, Status) :- atom(X), !,
 	'$find_in_path'(X,Y),
 	'$values'('$included_file',OY,Y),
-	( open(Y,'$csult',Stream), !,
-		'$loop'(Stream,Status), close(Stream)
+	( '$open'(Y,'$csult',Stream,0), !,
+		'$loop'(Stream,Status), '$close'(Stream)
 	;
 		throw(error(permission_error(input,stream,Y),include(X)))
 	),
@@ -236,10 +236,10 @@ reconsult(Fs) :-
 	  '$set_value'('$verbose',off)
 	),
 	'$find_in_path'(X,Y),
-	( open(Y,'$csult',Stream), !,
+	( '$open'(Y,'$csult',Stream,0), !,
 		'$record_loaded'(Stream),
 		( '$access_yap_flags'(15, 0) -> true ; '$skip_unix_comments'(Stream) ),
-		'$reconsult'(X,Stream), close(Stream)
+		'$reconsult'(X,Stream), '$close'(Stream)
 	;
 		'$output_error_message'(permission_error(input,stream,X),reconsult(X))
 	),
diff --git a/pl/debug.yap b/pl/debug.yap
index 7ca28ca1f..afe872afa 100644
--- a/pl/debug.yap
+++ b/pl/debug.yap
@@ -463,7 +463,7 @@ debugging :-
 	'$creepcall_dynamic_clause'(G,M,Cl).
 
 '$catch_spycall_stdpred'(G,M) :-
-	'$system_catch'('$spycall_stdpred'(G,M), Error, user:'$DebugError'(Error)).
+	'$system_catch'('$spycall_stdpred'(G,M), M, Error, user:'$DebugError'(Error)).
 
 '$spycall_stdpred'(G,M) :-
 	functor(G,F,N),
@@ -480,7 +480,7 @@ debugging :-
 
 
 '$call_clause'(G,M,Cl) :-
-	'$system_catch'('$do_execute_clause'(G,M,Cl),Error,user:'$DebugError'(Error)).
+	'$system_catch'('$do_execute_clause'(G,M,Cl),M,Error,user:'$DebugError'(Error)).
 
 '$do_execute_clause'(G,M,Cl) :-
 	'$some_recordedp'(M:G), !,
@@ -497,7 +497,7 @@ debugging :-
 	'$execute'(G,M,Cl) ; Next is Cl+1, '$set_value'(spy_cl,Next), fail.
 
 '$call_log_updclause'(G,M,Cl,Index) :-
-	'$system_catch'('$do_execute_log_upd_clause'(G,M,Cl,Index),Error,user:'$DebugError'(Error)).
+	'$system_catch'('$do_execute_log_upd_clause'(G,M,Cl,Index),M,Error,user:'$DebugError'(Error)).
 
 '$do_execute_log_upd_clause'(G,M,Cl,Index) :-
 	'$check_depth_for_interpreter'(D),
@@ -526,10 +526,10 @@ debugging :-
 	D1 is D0-1.
 
 '$debug_catch_call'(Clause,M,CP) :-
-	'$system_catch'('$call'(Clause,CP,Clause,M),Error,user:'$DebugError'(Error)).
+	'$system_catch'('$call'(Clause,CP,Clause,M),M,Error,user:'$DebugError'(Error)).
 
 '$call_dynamic_clause'(G,M,Cl) :-
-	'$system_catch'('$do_execute_dynamic_clause'(G,M,Cl),Error,user:'$DebugError'(Error)).
+	'$system_catch'('$do_execute_dynamic_clause'(G,M,Cl),M,Error,user:'$DebugError'(Error)).
 
 '$do_execute_dynamic_clause'(G,M,Cl) :-
 	'$check_depth_for_interpreter'(D),
@@ -544,7 +544,7 @@ debugging :-
         ).
 
 '$creepcallclause'(G,M,Cl) :-
-	'$system_catch'('$do_creep_execute'(G,M,Cl),Error,user:'$DebugError'(Error)).
+	'$system_catch'('$do_creep_execute'(G,M,Cl),M,Error,user:'$DebugError'(Error)).
 
 '$do_creep_execute'(G,M,Cl) :-
 	 % fast skip should ignore source mode
@@ -567,7 +567,7 @@ debugging :-
 	Next is Cl+1, '$set_value'(spy_cl,Next), fail.
 
 '$creepcall_log_upd_clause'(G,M,Cl,Index) :-
-	'$system_catch'('$do_creep_log_upd_execute'(G,M,Cl,Index),Error,user:'$DebugError'(Error)).
+	'$system_catch'('$do_creep_log_upd_execute'(G,M,Cl,Index),M,Error,user:'$DebugError'(Error)).
 
 '$do_creep_log_upd_execute'(G,M,Cl,Index) :-
 	'$check_depth_for_interpreter'(D),
@@ -592,10 +592,10 @@ debugging :-
         ).
 
 '$catch_creep_call'(Clause,M,CP) :-
-	'$system_catch'('$creep_call'(Clause,M,CP),Error,user:'$DebugError'(Error)).
+	'$system_catch'('$creep_call'(Clause,M,CP),M,Error,user:'$DebugError'(Error)).
 
 '$creepcall_dynamic_clause'(G,M,Cl) :-
-	'$system_catch'('$do_creep_execute_dynamic'(G,M,Cl),Error,user:'$DebugError'(Error)).
+	'$system_catch'('$do_creep_execute_dynamic'(G,M,Cl),M,Error,user:'$DebugError'(Error)).
 
 '$do_creep_execute_dynamic'(G,M,Cl) :-
 	'$check_depth_for_interpreter'(D),
@@ -988,6 +988,7 @@ debugging :-
 % do not try to handle other throws or aborts.
 %
 '$DebugError'(T) :- !,
+	'$trace'(exception,T),
 	throw(T).
 
 '$init_spy_cl'(G,M) :-
diff --git a/pl/directives.yap b/pl/directives.yap
index 1ac2d218e..135ee8190 100644
--- a/pl/directives.yap
+++ b/pl/directives.yap
@@ -38,7 +38,7 @@
 '$directive'(wait(_)).
 
 '$exec_directive'(multifile(D), _, M) :-
-	'$system_catch'('$multifile'(D, M),
+	'$system_catch'('$multifile'(D, M), M,
 	      Error,
 	      user:'$LoopError'(Error)).
 '$exec_directive'(discontiguous(D), _, M) :-
diff --git a/pl/errors.yap b/pl/errors.yap
index ca17cdf7d..0aca6ff18 100644
--- a/pl/errors.yap
+++ b/pl/errors.yap
@@ -46,312 +46,312 @@ print_message(Severity, Msg) :-
 print_message(error,error(Msg,Where)) :-
 	'$output_error_message'(Msg, Where), !.
 print_message(error,Throw) :-
-	format(user_error,"[ No handler for ball ~w ]~n", [Throw]).
+	'$format'(user_error,"[ No handler for ball ~w ]~n", [Throw]).
 print_message(informational,debug(trace)) :-
-	format(user_error,"[ The debugger will first creep -- showing everything (trace) ]~n",[]).
+	'$format'(user_error,"[ The debugger will first creep -- showing everything (trace) ]~n",[]).
 print_message(informational,M) :-
-	format(user_error,"[ ", []),
+	'$format'(user_error,"[ ", []),
 	'$do_print_message'(M),
-	format(user_error," ]", []).
+	'$format'(user_error," ]", []).
 print_message(warning,M) :-
-	format(user_error,"[ Warning: ", []),
+	'$format'(user_error,"[ Warning: ", []),
 	'$do_print_message'(M),
-	format(user_error," ]~n", []).
+	'$format'(user_error," ]~n", []).
 print_message(help,M) :-
-	format(user_error,"help on ~p",[M]).
+	'$format'(user_error,"help on ~p",[M]).
 
 
 '$do_print_message'(debug(trace)) :- !,
-	format(user_error,"[ The debugger will first creep -- showing everything (trace) ]~n",[]).
-'$do_print_message'(format(Msg, Args)) :- !,
-	format(user_error,Msg,Args).
+	'$format'(user_error,"[ The debugger will first creep -- showing everything (trace) ]~n",[]).
+'$do_print_message'('$format'(Msg, Args)) :- !,
+	'$format'(user_error,Msg,Args).
 '$do_print_message'(import(Pred,To,From,private)) :-
-	format(user_error,"importing private predicate ~w:~w to ~w",
+	'$format'(user_error,"importing private predicate ~w:~w to ~w",
 	[From,Pred,To]).
 '$do_print_message'(Messg) :-
-	format(user_error,"~q",Messg).
+	'$format'(user_error,"~q",Messg).
 
 '$output_error_message'(context_error(Goal,Who),Where) :-
-	format(user_error,"[ CONTEXT ERROR- ~w: ~w appeared in ~w ]~n",
+	'$format'(user_error,"[ CONTEXT ERROR- ~w: ~w appeared in ~w ]~n",
 	[Goal,Who,Where]).
 '$output_error_message'(domain_error(array_overflow,Opt), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: invalid index for array ~w ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: invalid index for array ~w ]~n",
 	[Where,Opt]).
 '$output_error_message'(domain_error(array_type,Opt), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: invalid static array type ~w ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: invalid static array type ~w ]~n",
 	[Where,Opt]).
 '$output_error_message'(domain_error(builtin_procedure,P), P) :-
-	format(user_error,"[ DOMAIN ERROR- non-iso built-in procedure  ~w ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- non-iso built-in procedure  ~w ]~n",
 	[P]).
 '$output_error_message'(domain_error(character_code_list,Opt), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: invalid list of codes ~w ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: invalid list of codes ~w ]~n",
 	[Where,Opt]).
 '$output_error_message'(domain_error(delete_file_option,Opt), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: invalid list of options ~w ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: invalid list of options ~w ]~n",
 	[Where,Opt]).
 '$output_error_message'(domain_error(operator_specifier,Op), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: invalid operator specifier ~w ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: invalid operator specifier ~w ]~n",
 	[Where,Op]).
 '$output_error_message'(domain_error(close_option,Opt), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: invalid close option ~w ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: invalid close option ~w ]~n",
 	[Where,Opt]).
 '$output_error_message'(domain_error(radix,Opt), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: invalid radix ~w ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: invalid radix ~w ]~n",
 	[Where,Opt]).
 '$output_error_message'(domain_error(shift_count_overflow,Opt), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: shift count overflow in ~w ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: shift count overflow in ~w ]~n",
 	[Where,Opt]).
 '$output_error_message'(domain_error(flag_value,F+V), W) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: invalid value ~w for flag ~w ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: invalid value ~w for flag ~w ]~n",
 	[W,V,F]).
 '$output_error_message'(domain_error(io_mode,N), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: invalid io mode ~w ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: invalid io mode ~w ]~n",
 	[Where,N]).
 '$output_error_message'(domain_error(mutable,N), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: invalid mutable ~w ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: invalid mutable ~w ]~n",
 	[Where,N]).
 '$output_error_message'(domain_error(module_decl_options,N), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: expect module declaration options, found ~w ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: expect module declaration options, found ~w ]~n",
 	[Where,N]).
 '$output_error_message'(domain_error(not_empty_list,_), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: found empty list ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: found empty list ]~n",
 	[Where]).
 '$output_error_message'(domain_error(not_less_than_zero,N), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: number ~w less than zero ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: number ~w less than zero ]~n",
 	[Where,N]).
 '$output_error_message'(domain_error(not_newline,N), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: number ~w not newline ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: number ~w not newline ]~n",
 	[Where,N]).
 '$output_error_message'(domain_error(not_zero,N), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: number ~w not zero ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: number ~w not zero ]~n",
 	[Where,N]).
 '$output_error_message'(domain_error(operator_priority,N), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: ~w invalid operator priority ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w invalid operator priority ]~n",
 	[Where,N]).
 '$output_error_message'(domain_error(operator_specifier,N), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: ~w invalid operator specifier ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w invalid operator specifier ]~n",
 	[Where,N]).
 '$output_error_message'(domain_error(read_option,N), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: ~w invalid option to read ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w invalid option to read ]~n",
 	[Where,N]).
 '$output_error_message'(domain_error(semantics_indicator,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected predicate indicator, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected predicate indicator, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(domain_error(source_sink,N), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: ~w is not a source sink term ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w is not a source sink term ]~n",
 	[Where,N]).
 '$output_error_message'(domain_error(stream,What), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: ~w not a stream ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w not a stream ]~n",
 	[Where,What]).
 '$output_error_message'(domain_error(stream_or_alias,What), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: ~w not a stream ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w not a stream ]~n",
 	[Where,What]).
 '$output_error_message'(domain_error(stream_option,What), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: ~w not a stream option ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w not a stream option ]~n",
 	[Where,What]).
 '$output_error_message'(domain_error(stream_position,What), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: ~w not a stream position ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w not a stream position ]~n",
 	[Where,What]).
 '$output_error_message'(domain_error(stream_property,What), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: ~w not a stream property ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w not a stream property ]~n",
 	[Where,What]).
 '$output_error_message'(domain_error(syntax_error_handler,What), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: ~w not a syntax error handler ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w not a syntax error handler ]~n",
 	[Where,What]).
 '$output_error_message'(domain_error(time_out_spec,What), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: ~w not a valid specification for a time out ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w not a valid specification for a time out ]~n",
 	[Where,What]).
 '$output_error_message'(domain_error(write_option,N), Where) :-
-	format(user_error,"[ DOMAIN ERROR- ~w: ~w invalid option to write ]~n",
+	'$format'(user_error,"[ DOMAIN ERROR- ~w: ~w invalid option to write ]~n",
 	[Where,N]).
 '$output_error_message'(existence_error(array,F), W) :-
-	format(user_error,"[ EXISTENCE ERROR- ~w could not open array ~w ]~n",
+	'$format'(user_error,"[ EXISTENCE ERROR- ~w could not open array ~w ]~n",
 	[W,F]).
 '$output_error_message'(existence_error(procedure,P), _) :-
-	format(user_error,"[ EXISTENCE ERROR- procedure ~w undefined ]~n",
+	'$format'(user_error,"[ EXISTENCE ERROR- procedure ~w undefined ]~n",
 	[P]).
 '$output_error_message'(existence_error(source_sink,F), W) :-
-	format(user_error,"[ EXISTENCE ERROR- ~w could not find file ~w ]~n",
+	'$format'(user_error,"[ EXISTENCE ERROR- ~w could not find file ~w ]~n",
 	[W,F]).
 '$output_error_message'(existence_error(stream,Stream), Where) :-
-	format(user_error,"[ EXISTENCE ERROR- ~w: ~w not an open stream ]~n",
+	'$format'(user_error,"[ EXISTENCE ERROR- ~w: ~w not an open stream ]~n",
 	[Where,Stream]).
 '$output_error_message'(evaluation_error(int_overflow), Where) :-
-	format(user_error,"[ INTEGER OVERFLOW ERROR- ~w ]~n",
+	'$format'(user_error,"[ INTEGER OVERFLOW ERROR- ~w ]~n",
 	[Where]).
 '$output_error_message'(evaluation_error(float_overflow), Where) :-
-	format(user_error,"[ FLOATING POINT OVERFLOW ERROR- ~w ]~n",
+	'$format'(user_error,"[ FLOATING POINT OVERFLOW ERROR- ~w ]~n",
 	[Where]).
 '$output_error_message'(evaluation_error(undefined), Where) :-
-	format(user_error,"[ UNDEFINED ARITHMETIC RESULT ERROR- ~w ]~n",
+	'$format'(user_error,"[ UNDEFINED ARITHMETIC RESULT ERROR- ~w ]~n",
 	[Where]).
 '$output_error_message'(evaluation_error(underflow), Where) :-
-	format(user_error,"[ UNDERFLOW ERROR- ~w ]~n",
+	'$format'(user_error,"[ UNDERFLOW ERROR- ~w ]~n",
 	[Where]).
 '$output_error_message'(evaluation_error(float_underflow), Where) :-
-	format(user_error,"[ FLOATING POINT UNDERFLOW ERROR- ~w ]~n",
+	'$format'(user_error,"[ FLOATING POINT UNDERFLOW ERROR- ~w ]~n",
 	[Where]).
 '$output_error_message'(evaluation_error(zero_divisor), Where) :-
-	format(user_error,"[ ZERO DIVISOR ERROR- ~w ]~n",
+	'$format'(user_error,"[ ZERO DIVISOR ERROR- ~w ]~n",
 	[Where]).
 '$output_error_message'(instantiation_error, Where) :-
-	format(user_error,"[ INSTANTIATION ERROR- ~w: expected bound value ]~n",
+	'$format'(user_error,"[ INSTANTIATION ERROR- ~w: expected bound value ]~n",
 	[Where]).
 '$output_error_message'(permission_error(access,private_procedure,P), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: cannot see clauses for ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: cannot see clauses for ~w ]~n",
 	[Where,P]).
 '$output_error_message'(permission_error(access,static_procedure,P), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: cannot access static procedure ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: cannot access static procedure ~w ]~n",
 	[Where,P]).
 '$output_error_message'(permission_error(alias,new,P), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: cannot create alias ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: cannot create alias ~w ]~n",
 	[Where,P]).
 '$output_error_message'(permission_error(create,array,P), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: cannot create array ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: cannot create array ~w ]~n",
 	[Where,P]).
 '$output_error_message'(permission_error(create,operator,P), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: cannot create operator ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: cannot create operator ~w ]~n",
 	[Where,P]).
 '$output_error_message'(permission_error(input,binary_stream,Stream), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: cannot read from binary stream ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: cannot read from binary stream ~w ]~n",
 	[Where,Stream]).
 '$output_error_message'(permission_error(input,closed_stream,Stream), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: trying to read from closed stream ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: trying to read from closed stream ~w ]~n",
 	[Where,Stream]).
 '$output_error_message'(permission_error(input,past_end_of_stream,Stream), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: past end of stream ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: past end of stream ~w ]~n",
 	[Where,Stream]).
 '$output_error_message'(permission_error(input,stream,Stream), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: cannot read from ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: cannot read from ~w ]~n",
 	[Where,Stream]).
 '$output_error_message'(permission_error(input,text_stream,Stream), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: cannot read from text stream ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: cannot read from text stream ~w ]~n",
 	[Where,Stream]).
 '$output_error_message'(permission_error(modify,dynamic_procedure,_), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: modifying a dynamic procedure ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: modifying a dynamic procedure ]~n",
 	[Where]).
 '$output_error_message'(permission_error(modify,flag,W), _) :-
-	format(user_error,"[ PERMISSION ERROR- cannot modify flag ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- cannot modify flag ~w ]~n",
 	[W]).
 '$output_error_message'(permission_error(modify,operator,W), _) :-
-	format(user_error,"[ PERMISSION ERROR- T cannot declare ~w an operator ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- T cannot declare ~w an operator ]~n",
 	[W]).
 '$output_error_message'(permission_error(modify,static_procedure,_), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: modifying a static procedure ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: modifying a static procedure ]~n",
 	[Where]).
 '$output_error_message'(permission_error(modify,static_procedure_in_use,_), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: modifying a static procedure in use ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: modifying a static procedure in use ]~n",
 	[Where]).
 '$output_error_message'(permission_error(open,source_sink,Stream), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: cannot open file ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: cannot open file ~w ]~n",
 	[Where,Stream]).
 '$output_error_message'(permission_error(output,binary_stream,Stream), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: cannot write to binary stream ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: cannot write to binary stream ~w ]~n",
 	[Where,Stream]).
 '$output_error_message'(permission_error(output,stream,Stream), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: cannot write to ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: cannot write to ~w ]~n",
 	[Where,Stream]).
 '$output_error_message'(permission_error(output,text_stream,Stream), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: cannot write to text stream ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: cannot write to text stream ~w ]~n",
 	[Where,Stream]).
 '$output_error_message'(permission_error(resize,array,P), Where) :-
-	format(user_error,"[ PERMISSION ERROR- ~w: cannot resize array ~w ]~n",
+	'$format'(user_error,"[ PERMISSION ERROR- ~w: cannot resize array ~w ]~n",
 	[Where,P]).
 '$output_error_message'(representation_error(character), Where) :-
-	format(user_error,"[ REPRESENTATION ERROR- ~w: expected character ]~n",
+	'$format'(user_error,"[ REPRESENTATION ERROR- ~w: expected character ]~n",
 	[Where]).
 '$output_error_message'(representation_error(character_code), Where) :-
-	format(user_error,"[ REPRESENTATION ERROR- ~w: expected character code ]~n",
+	'$format'(user_error,"[ REPRESENTATION ERROR- ~w: expected character code ]~n",
 	[Where]).
 '$output_error_message'(representation_error(max_arity), Where) :-
-	format(user_error,"[ REPRESENTATION ERROR- ~w: number too big ]~n",
+	'$format'(user_error,"[ REPRESENTATION ERROR- ~w: number too big ]~n",
 	[Where]).
 '$output_error_message'(syntax_error(Error), Where) :-
-	format(user_error,"[ SYNTAX ERROR- ~w: ~w ]~n",
+	'$format'(user_error,"[ SYNTAX ERROR- ~w: ~w ]~n",
 	[Where, Error]).
 '$output_error_message'(system_error, Where) :-
-	format(user_error,"[ SYSTEM ERROR- ~w ]~n",
+	'$format'(user_error,"[ SYSTEM ERROR- ~w ]~n",
 	[Where]).
 '$output_error_message'(system_error(Message), Where) :-
-	format(user_error,"[ SYSTEM ERROR- ~w at ~w]~n",
+	'$format'(user_error,"[ SYSTEM ERROR- ~w at ~w]~n",
 	[Message,Where]).
 '$output_error_message'(type_error(T,_,Err,M), _Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected ~w, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected ~w, got ~w ]~n",
 	[T,Err,M]).
 '$output_error_message'(type_error(array,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected array, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected array, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(atom,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected atom, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected atom, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(atomic,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected atomic, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected atomic, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(byte,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected byte, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected byte, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(callable,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected callable goal, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected callable goal, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(character,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected character, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected character, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(character_code,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected character code, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected character code, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(compound,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected compound, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected compound, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(db_reference,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected data base reference, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected data base reference, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(db_term,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected data base term, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected data base term, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(evaluable,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected evaluable term, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected evaluable term, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(float,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected float, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected float, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(in_byte,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected byte, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected byte, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(in_character,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected atom character, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected atom character, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(in_character_code,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected character code, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected character code, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(integer,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected integer, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected integer, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(key,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected database key, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected database key, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(leash_mode,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected modes for leash, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected modes for leash, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(list,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected list, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected list, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(number,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected number, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected number, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(pointer,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected pointer, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected pointer, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(predicate_indicator,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected predicate indicator, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected predicate indicator, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(unsigned_byte,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected unsigned byte, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected unsigned byte, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(type_error(variable,W), Where) :-
-	format(user_error,"[ TYPE ERROR- ~w: expected unbound variable, got ~w ]~n",
+	'$format'(user_error,"[ TYPE ERROR- ~w: expected unbound variable, got ~w ]~n",
 	[Where,W]).
 '$output_error_message'(unknown, Where) :-
-	format(user_error,"[ EXISTENCE ERROR- procedure ~w undefined ]~n",
+	'$format'(user_error,"[ EXISTENCE ERROR- procedure ~w undefined ]~n",
 	[Where]).
 
 
diff --git a/pl/listing.yap b/pl/listing.yap
index 471c2cd2c..fbacaebe6 100644
--- a/pl/listing.yap
+++ b/pl/listing.yap
@@ -75,7 +75,7 @@ portray_clause(Pred) :-
 '$write_clause'(Head,Body) :-
         writeq(Head),
         ( Body = true  ;
-                tab(1), write((:-)),
+                '$tab'(1), write((:-)),
                 '$write_body'(Body,3,',')
         ),
         put("."), nl,
@@ -90,50 +90,50 @@ portray_clause(Pred) :-
         '$write_body'(Q,I,',').
 '$write_body'((P->Q;S),I,_) :-
 	!,
-	nl, tab(I-2), put("("),
+	nl, '$tab'(I-2), put("("),
 	'$write_body'(P,I,'('),
 	put("-"), put(">"),
 	'$write_body'(Q,I,'->'),
 	put(";"),
 	'$write_body'(S,I,';'),
-	tab(1), put(")").
+	'$tab'(1), put(")").
 '$write_body'((P->Q|S),I,_) :-
 	!,
-	nl, tab(I-2), put("("),
+	nl, '$tab'(I-2), put("("),
 	'$write_body'(P,I,'('),
 	put("-"), put(">"),
 	'$write_body'(Q,I,'->'),
 	put("|"),
 	'$write_body'(S,I,'|'),
-	tab(1), put(")").
+	'$tab'(1), put(")").
 '$write_body'((P->Q),I,_) :-
 	!,
-	nl, tab(I-2), put("("),
+	nl, '$tab'(I-2), put("("),
         '$write_body'(P,I,'('),
         put("-"), put(">"),
         '$write_body'(Q,I,'->'),
-        tab(1), put(")").
+        '$tab'(1), put(")").
 '$write_body'((P;Q),I,_) :-
         !,
-        nl, tab(I-2), put("("),
+        nl, '$tab'(I-2), put("("),
         '$write_body'(P,I,'('),
         put(";"),
         '$write_body'(Q,I,';'),
-        tab(1), put(")").
+        '$tab'(1), put(")").
 '$write_body'((P|Q),I,_) :-
         !,
-        nl, tab(I-2), put("("),
+        nl, '$tab'(I-2), put("("),
         '$write_body'(P,I,'('),
         put("|"),
         '$write_body'(Q,I,'|'),
-        tab(1), put(")").
+        '$tab'(1), put(")").
 '$write_body'((P|Q),I,_) :-
         !,
-        nl, tab(I-2), put("("),
+        nl, '$tab'(I-2), put("("),
         '$write_body'(P,I,'('),
         put("|"),
         '$write_body'(Q,I,'|'),
-        tab(1), put(")").
+        '$tab'(1), put(")").
 '$write_body'(X,I,T) :-
         '$beforelit'(T,I),
         writeq(X).
@@ -141,8 +141,8 @@ portray_clause(Pred) :-
 '$aftercomma'(',',I,I) :- !.
 '$aftercomma'(_,I0,I) :- I is I0+3.
 
-'$beforelit'('(',_) :- !, tab(1).
-'$beforelit'(_,I) :- nl, tab(I).
+'$beforelit'('(',_) :- !, '$tab'(1).
+'$beforelit'(_,I) :- nl, '$tab'(I).
 
 '$beautify_vars'(T) :-
 	'$list_get_vars'(T,[],L),
diff --git a/pl/modules.yap b/pl/modules.yap
index 68563b22e..fcc4ea987 100644
--- a/pl/modules.yap
+++ b/pl/modules.yap
@@ -51,7 +51,7 @@ use_module(File,Imports) :-
 	atom(File), !,
 	'$current_module'(M),
 	'$find_in_path'(File,X),
-	( open(X,'$csult',Stream), !,
+	( '$open'(X,'$csult',Stream,0), !,
 	'$consulting_file_name'(Stream,TrueFileName),
 	( '$loaded'(Stream) -> true
 	     ;
@@ -60,12 +60,12 @@ use_module(File,Imports) :-
 	     '$recorda'('$importing','$importing'(TrueFileName),R),
 	     '$reconsult'(File,Stream)
 	 ),
-	 close(Stream),
+	 '$close'(Stream),
 	 ( var(R) -> true; erased(R) -> true; erase(R)),
 	 ( '$recorded'('$module','$module'(TrueFileName,Mod,Publics),_) ->
 	     '$use_preds'(Imports,Publics,Mod,M)
 	 ;
-	 format(user_error,'[ use_module/2 can not find a module in file ~w]~n',File),
+	 '$format'(user_error,'[ use_module/2 can not find a module in file ~w]~n',File),
 	 fail
      )
     ;  
@@ -74,7 +74,7 @@ use_module(File,Imports) :-
 use_module(library(File),Imports) :- !,
 	'$current_module'(M),
 	'$find_in_path'(library(File),X),
-	( open(X,'$csult',Stream), !,
+	( '$open'(X,'$csult',Stream,0), !,
 	'$consulting_file_name'(Stream,TrueFileName),
 	( '$loaded'(Stream) -> true
 	     ;
@@ -83,12 +83,12 @@ use_module(library(File),Imports) :- !,
 	     '$recorda'('$importing','$importing'(TrueFileName),R),
 	     '$reconsult'(library(File),Stream)
 	 ),
-	 close(Stream),
+	 '$close'(Stream),
 	 ( var(R) -> true; erased(R) -> true; erase(R)),
 	 ( '$recorded'('$module','$module'(TrueFileName,Mod,Publics),_) ->
 	     '$use_preds'(Imports,Publics,Mod,M)
 	 ;
-	 format(user_error,'[ use_module/2 can not find a module in file ~w]~n',[File]),
+	 '$format'(user_error,'[ use_module/2 can not find a module in file ~w]~n',[File]),
 	 fail
      )
     ;  
@@ -100,7 +100,7 @@ use_module(V,Decls) :-
 use_module(Module,File,Imports) :-
 	'$current_module'(M),
 	'$find_in_path'(File,X),
-	( open(X,'$csult',Stream), !,
+	( '$open'(X,'$csult',Stream,0), !,
 	'$consulting_file_name'(Stream,TrueFileName),
 	( '$loaded'(Stream) -> true
 	     ;
@@ -109,12 +109,12 @@ use_module(Module,File,Imports) :-
 	     '$recorda'('$importing','$importing'(TrueFileName),R),
 	     '$reconsult'(File,Stream)
 	 ),
-	 close(Stream),
+	 '$close'(Stream),
 	 ( var(R) -> true; erased(R) -> true; erase(R)),
 	 ( '$recorded'('$module','$module'(TrueFileName,Module,Publics),_) ->
 	     '$use_preds'(Imports,Publics,Module,M)
 	 ;
-	     format(user_error,'[ use_module/2 can not find module ~w in file ~w]~n',[Module,File]),
+	     '$format'(user_error,'[ use_module/2 can not find module ~w in file ~w]~n',[Module,File]),
 	 fail
      )
     ;  
@@ -132,7 +132,7 @@ use_module(Module,V,Decls) :-
 	'$module_dec'(N,P).
 '$module'(consult,N,P) :-
 	( '$recorded'('$module','$module'(F,N,_),_),
-	     format(user_error,'[ Module ~w was already defined in file ~w]~n',[N,F]),
+	     '$format'(user_error,'[ Module ~w was already defined in file ~w]~n',[N,F]),
 		'$abolish_module_data'(N),
 		fail
 	;
@@ -212,7 +212,7 @@ module(N) :-
 '$import'([N/K|L],M,T) :-
 	integer(K), atom(N), !,
 	( '$check_import'(M,T,N,K) ->
-%	    format(user_error,'[vsc1: Importing ~w to ~w]~n',[M:N/K,T]),
+%	    '$format'(user_error,'[vsc1: Importing ~w to ~w]~n',[M:N/K,T]),
 	     ( T = user ->
 	       recordz('$import','$import'(M,user,N,K),_)
              ;
@@ -223,13 +223,13 @@ module(N) :-
 	),
 	'$import'(L,M,T).
 '$import'([PS|L],M,T) :-
-	format(user_error,'[Illegal pred specification(~w) in module declaration for module ~w]~n',[PS,M]),
+	'$format'(user_error,'[Illegal pred specification(~w) in module declaration for module ~w]~n',[PS,M]),
 	'$import'(L,M,T).
 
 '$check_import'(M,T,N,K) :-
     '$recorded'('$import','$import'(M1,T0,N,K),R), T0 == T, M1 \= M, /* ZP */ !,
-    format(user_error,'NAME CLASH: ~w was already imported to module ~w;~n',[M1:N/K,T]),
-    format(user_error,'            Do you want to import it from ~w ? [y or n] ',M),
+    '$format'(user_error,'NAME CLASH: ~w was already imported to module ~w;~n',[M1:N/K,T]),
+    '$format'(user_error,'            Do you want to import it from ~w ? [y or n] ',M),
     repeat,
 	get0(C), '$skipeol'(C),
 	( C is "y" -> erase(R), !;
@@ -248,9 +248,9 @@ module(N) :-
 	print_message(warning,import(N/K,Mod,M,private))
     ),
     ( '$check_import'(M,Mod,N,K) -> 
-	%	     format(user_error,'[ Importing ~w to ~w]~n',[M:N/K,Mod]),
+	%	     '$format'(user_error,'[ Importing ~w to ~w]~n',[M:N/K,Mod]),
         %            '$trace_module'(importing(M:N/K,Mod)),
-%         format(user_error,'[vsc2: Importing ~w to ~w]~n',[M:N/K,T]),
+%         '$format'(user_error,'[vsc2: Importing ~w to ~w]~n',[M:N/K,T]),
 	  (Mod = user ->
              recordz('$import','$import'(M,user,N,K),_)
 	     ;
@@ -464,9 +464,9 @@ module(N) :-
 	functor(G,F,N),
 	user:'$meta_predicate'(F,Mod,N,D), !,
 	functor(G1,F,N),
-%	format(user_error,'[expanding ~w:~w in ~w',[Mod,G,MP]),
+%	'$format'(user_error,'[expanding ~w:~w in ~w',[Mod,G,MP]),
 	'$meta_expansion_loop'(N,D,G,G1,HVars,MP).
-%	format(user_error,' gives ~w~n]',[G1]).
+%	'$format'(user_error,' gives ~w~n]',[G1]).
 
 % expand argument
 '$meta_expansion_loop'(0,_,_,_,_,_) :- !.
diff --git a/pl/preds.yap b/pl/preds.yap
index 53afc9425..dbb09876f 100644
--- a/pl/preds.yap
+++ b/pl/preds.yap
@@ -473,7 +473,7 @@ abolish(X) :-
 	'$access_yap_flags'(8, 2), % only do this in sicstus mode
 	'$undefined'(G, Module),
 	functor(G,Name,Arity),
-	format(user_error,'[ Warning: abolishing undefined predicate (~w:~w/~w) ]~n',[Module,Name,Arity]),
+	'$format'(user_error,"[ Warning: abolishing undefined predicate (~w:~w/~w) ]~n",[Module,Name,Arity]),
 	fail.
 % I cannot allow modifying static procedures in YAPOR
 % this code has to be here because of abolish/2
diff --git a/pl/protect.yap b/pl/protect.yap
index a0d92c9b8..505ae0d6d 100644
--- a/pl/protect.yap
+++ b/pl/protect.yap
@@ -35,9 +35,9 @@
 '$make_system_preds'(woken_att_do) :- !.
 '$make_system_preds'(convert_att_var) :- !.
 '$make_system_preds'(Name) :- 
-%	format("~NProtecting ~a",Name),
+%	'$format'("~NProtecting ~a",Name),
 	'$pred_defined_for'(Name,Pred),
-%	format("~NProtecting ~q",Pred),	
+%	'$format'("~NProtecting ~q",Pred),	
 	'$protect_system_pred'(Pred),
 	fail.
 '$make_system_preds'(_).
diff --git a/pl/setof.yap b/pl/setof.yap
index 73618dd3d..5b8437b02 100644
--- a/pl/setof.yap
+++ b/pl/setof.yap
@@ -32,7 +32,7 @@ _^Goal :-
 
 
 findall(Template, Generator, Answers) :-
-	'$check_list'(Answers, findall(Template, Generator, Answers)),
+	'$check_list_for_bags'(Answers, findall(Template, Generator, Answers)),
 	'$init_db_queue'(Ref),
 	'$findall'(Template, Generator, Ref, [], Answers).
 
@@ -84,7 +84,7 @@ findall(Template, Generator, Answers, SoFar) :-
 % This is the setof predicate
 
 setof(Template, Generator, Set) :-
-	'$check_list'(Set, setof(Template, Generator, Set)),
+	'$check_list_for_bags'(Set, setof(Template, Generator, Set)),
 	'$bagof'(Template, Generator, Bag),
 	'$sort'(Bag, Set).
 
@@ -98,7 +98,7 @@ bagof(Template, Generator, Bag) :-
 	'$bagof'(Template, Generator, Bag).
 	
 '$bagof'(Template, Generator, Bag) :-
-	'$check_list'(Bag, bagof(Template, Generator, Bag)),
+	'$check_list_for_bags'(Bag, bagof(Template, Generator, Bag)),
 	'$variables_in_term'(Template, [], TemplateV),
 	'$excess_vars'(Generator, TemplateV, [], FreeVars),
 	FreeVars \== [],
@@ -215,3 +215,10 @@ all(T,G,S) :- '$recorda'('$$one','$',R), (
 '$$split'([T1|Tn],T,X,S1,[T1|S2]) :- '$$split'(Tn,T,X,S1,S2).
 
 
+'$check_list_for_bags'(V, _) :- var(V), !.
+'$check_list_for_bags'([], _) :- !.
+'$check_list_for_bags'([_|B], T) :- !,
+	'$check_list_for_bags'(B,T).
+'$check_list_for_bags'(S, T) :-
+	throw(error(type_error(list,S),T)).
+
diff --git a/pl/sockets.yap b/pl/sockets.yap
index fceaf1410..8f36a893f 100644
--- a/pl/sockets.yap
+++ b/pl/sockets.yap
@@ -22,8 +22,8 @@ socket_accept(S,F) :-
 	socket_accept(S, _, F).
 
 socket_select(Socks, OutSocks, TimeOut, Streams, OutStreams) :-
-	'$check_list'(Socks, socket_select(Socks, OutSocks, TimeOut, Streams, OutStreams)),
-	'$check_list'(Streams, socket_select(Socks, OutSocks, TimeOut, Streams, OutStreams)),
+	'$check_list_for_sockets'(Socks, socket_select(Socks, OutSocks, TimeOut, Streams, OutStreams)),
+	'$check_list_for_sockets'(Streams, socket_select(Socks, OutSocks, TimeOut, Streams, OutStreams)),
 	'$select_cp_fds'(Socks, Streams, Fds),
 	'$check_select_time'(TimeOut, Sec, USec, socket_select(Socks, OutSocks, TimeOut, Streams, OutStreams)),
 	'$socket_select'(Fds, Sec, USec, NFds),
@@ -32,12 +32,12 @@ socket_select(Socks, OutSocks, TimeOut, Streams, OutStreams) :-
 	
 
 /* check whether a list of options is valid */
-'$check_list'(V,G) :- var(V), !,
+'$check_list_for_sockets'(V,G) :- var(V), !,
 	throw(error(instantiation_error,G)).
-'$check_list'([],_) :- !.
-'$check_list'([_|T],G) :- !,
- 	'$check_list'(T,G).
-'$check_io_opts'(T,G) :-
+'$check_list_for_sockets'([],_) :- !.
+'$check_list_for_sockets'([_|T],G) :- !,
+ 	'$check_list_for_sockets'(T,G).
+'$check_list_for_sockets'(T,G) :-
 	throw(error(type_error(list,T),G)).
 
 '$select_cp_fds'([], Fds, Fds).
diff --git a/pl/utils.yap b/pl/utils.yap
index 23d06b43c..54b07ac0e 100644
--- a/pl/utils.yap
+++ b/pl/utils.yap
@@ -361,37 +361,37 @@ statistics :-
 
 '$statistics'(Runtime,CPUtime,Walltime,HpSpa,HpInUse,_HpMax,TrlSpa, TrlInUse,_TrlMax,StkSpa, GlobInU, LocInU,GlobMax,LocMax,NOfHO,TotHOTime,NOfSO,TotSOTime,NOfTO,TotTOTime,NOfGC,TotGCTime,TotGCSize) :-
 	TotalMemory is HpSpa+StkSpa+TrlSpa,
-	format(user_error,"memory (total)~t~d bytes~35+~n", [TotalMemory]),
-	format(user_error,"   program space~t~d bytes~35+", [HpSpa]),
-	format(user_error,":~t  ~d in use~19+", [HpInUse]),
+	'$format'(user_error,"memory (total)~t~d bytes~35+~n", [TotalMemory]),
+	'$format'(user_error,"   program space~t~d bytes~35+", [HpSpa]),
+	'$format'(user_error,":~t  ~d in use~19+", [HpInUse]),
 	HpFree is HpSpa-HpInUse,
-	format(user_error,",~t  ~d free~19+~n", [HpFree]),
-	format(user_error,"   stack space~t~d bytes~35+", [StkSpa]),
+	'$format'(user_error,",~t  ~d free~19+~n", [HpFree]),
+	'$format'(user_error,"   stack space~t~d bytes~35+", [StkSpa]),
 	StackInUse is GlobInU+LocInU,
-	format(user_error,":~t  ~d in use~19+", [StackInUse]),
+	'$format'(user_error,":~t  ~d in use~19+", [StackInUse]),
 	StackFree is StkSpa-StackInUse,
-	format(user_error,",~t  ~d free~19+~n", [StackFree]),
-	format(user_error,"     global stack:~t~35+", []),
-	format(user_error," ~t  ~d in use~19+", [GlobInU]),
-	format(user_error,",~t  ~d max~19+~n", [GlobMax]),
-	format(user_error,"      local stack:~t~35+", []),
-	format(user_error," ~t  ~d in use~19+", [LocInU]),
-	format(user_error,",~t  ~d max~19+~n", [LocMax]),
-	format(user_error,"   trail stack~t~d bytes~35+", [TrlSpa]),
-	format(user_error,":~t  ~d in use~19+", [TrlInUse]),
+	'$format'(user_error,",~t  ~d free~19+~n", [StackFree]),
+	'$format'(user_error,"     global stack:~t~35+", []),
+	'$format'(user_error," ~t  ~d in use~19+", [GlobInU]),
+	'$format'(user_error,",~t  ~d max~19+~n", [GlobMax]),
+	'$format'(user_error,"      local stack:~t~35+", []),
+	'$format'(user_error," ~t  ~d in use~19+", [LocInU]),
+	'$format'(user_error,",~t  ~d max~19+~n", [LocMax]),
+	'$format'(user_error,"   trail stack~t~d bytes~35+", [TrlSpa]),
+	'$format'(user_error,":~t  ~d in use~19+", [TrlInUse]),
 	TrlFree is TrlSpa-TrlInUse,
-	format(user_error,",~t  ~d free~19+~n", [TrlFree]),
+	'$format'(user_error,",~t  ~d free~19+~n", [TrlFree]),
 	OvfTime is TotHOTime+TotSOTime+TotTOTime,
-	format(user_error,"~n~t~3f~12+ sec. for ~w code, ~w stack, and ~w trail space overflows~n",
+	'$format'(user_error,"~n~t~3f~12+ sec. for ~w code, ~w stack, and ~w trail space overflows~n",
 	       [OvfTime,NOfHO,NOfSO,NOfTO]),
-	format(user_error,"~t~3f~12+ sec. for ~w garbage collections which collected ~d bytes~n",
+	'$format'(user_error,"~t~3f~12+ sec. for ~w garbage collections which collected ~d bytes~n",
 	       [TotGCTime,NOfGC,TotGCSize]),
 	RTime is float(Runtime)/1000,
-	format(user_error,"~t~3f~12+ sec. runtime~n", [RTime]),
+	'$format'(user_error,"~t~3f~12+ sec. runtime~n", [RTime]),
 	CPUTime is float(CPUtime)/1000,
-	format(user_error,"~t~3f~12+ sec. cputime~n", [CPUTime]),
+	'$format'(user_error,"~t~3f~12+ sec. cputime~n", [CPUTime]),
 	WallTime is float(Walltime)/1000,
-	format(user_error,"~t~3f~12+ sec. elapsed time~n~n", [WallTime]),
+	'$format'(user_error,"~t~3f~12+ sec. elapsed time~n~n", [WallTime]),
 	fail.
 '$statistics'(_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_).
 
@@ -492,7 +492,7 @@ unknown(V0,V) :-
 '$unknown_warning'(P) :-
 	P=M:F,
 	functor(F,Na,Ar),
-	format(user_error,"[ EXISTENCE ERROR: ~w, procedure ~w:~w/~w undefined ]~n",
+	'$format'(user_error,"[ EXISTENCE ERROR: ~w, procedure ~w:~w/~w undefined ]~n",
 	[P,M,Na,Ar]),
 	fail.
 
diff --git a/pl/yio.yap b/pl/yio.yap
index 421bc27c5..6dcc9792b 100644
--- a/pl/yio.yap
+++ b/pl/yio.yap
@@ -292,7 +292,7 @@ seeing(File) :- current_input(Stream),
 	'$user_file_name'(Stream,NFile),
 	( '$user_file_name'(user_input,NFile) -> File = user ; NFile = File).
 
-seen :- current_input(Stream), close(Stream), set_input(user).
+seen :- current_input(Stream), '$close'(Stream), set_input(user).
 
 tell(user) :- !, set_output(user_output).
 tell(F) :- var(F), !,
@@ -309,7 +309,7 @@ telling(File) :- current_output(Stream),
 	'$user_file_name'(Stream,NFile),
 	( '$user_file_name'(user_output,NFile) -> File = user ; File = NFile ).
 
-told :- current_output(Stream), close(Stream), set_output(user).
+told :- current_output(Stream), '$close'(Stream), set_output(user).
 
 
 /* Term IO	*/
@@ -734,7 +734,7 @@ stream_position(user,N) :- !,
 	'$show_stream_position'(user_input,N).
 stream_position(A,N) :- 
 	atom(A),
-	current_stream(_,_,S), '$user_file_name'(S,A), !,
+	'$current_stream'(_,_,S), '$user_file_name'(S,A), !,
 	'$show_stream_position'(S,N).
 stream_position(S,N) :-
 	'$show_stream_position'(S,N).
@@ -743,7 +743,7 @@ stream_position(user,N,M) :- !,
 	'$stream_position'(user_input,N,M).
 stream_position(A,N,M) :- 
 	atom(A),
-	current_stream(_,_,S), '$user_file_name'(S,A), !,
+	'$current_stream'(_,_,S), '$user_file_name'(S,A), !,
 	'$stream_position'(S,N,M).
 stream_position(S,N,M) :-
 	'$stream_position'(S,N,M).
@@ -763,17 +763,17 @@ set_stream_position(user,N) :- !,
 	'$set_stream_position'(user_input,N).
 set_stream_position(A,N) :- 
 	atom(A),
-	current_stream(_,_,S), '$user_file_name'(S,A), !,
+	'$current_stream'(_,_,S), '$user_file_name'(S,A), !,
 	'$set_stream_position'(S,N).
 set_stream_position(S,N) :-
 	'$set_stream_position'(S,N).
 
 stream_property(Stream, Prop) :-  var(Prop), !,
-        (var(Stream) -> current_stream(_,_,Stream) ; true),
+        (var(Stream) -> '$current_stream'(_,_,Stream) ; true),
         '$generate_prop'(Prop),
 	'$stream_property'(Stream, Prop).
 stream_property(Stream, Props) :-  var(Stream), !,
-	current_stream(_,_,Stream),
+	'$current_stream'(_,_,Stream),
 	'$stream_property'(Stream, Props).
 stream_property(Stream, Props) :-
 	'$check_stream'(Stream), !,
@@ -798,7 +798,7 @@ stream_property(Stream, Props) :-
 '$stream_property'(Stream, Props0) :-
 	'$check_stream_props'(Props0, Props),
 	'$check_io_opts'(Props, stream_property(Stream, Props)),
-	current_stream(F,Mode,Stream),
+	'$current_stream'(F,Mode,Stream),
 	'$process_stream_properties'(Props, Stream, F, Mode).
 
 '$check_stream_props'([], []) :- !.
@@ -883,9 +883,9 @@ absolute_file_name(RelFile, AbsFile) :-
 '$exists'(F,Mode,AbsFile) :-
 	'$get_value'(fileerrors,V),
 	'$set_value'(fileerrors,0),
-	( open(F,Mode,S), !,
+	( '$open'(F,Mode,S,0), !,
 	    '$file_name'(S, AbsFile),
-	     close(S), '$set_value'(fileerrors,V);
+	     '$close'(S), '$set_value'(fileerrors,V);
 	     '$set_value'(fileerrors,V), fail).
 
 
@@ -902,3 +902,7 @@ current_char_conversion(X,Y) :-
 	'$fetch_char_conversion'(List,X,Y).
 
 
+current_stream(File, Opts, Stream) :-
+	'$current_stream'(File, Opts, Stream).
+
+