diff --git a/C/absmi.c b/C/absmi.c
index e9f2b56eb..4fc9f3b02 100644
--- a/C/absmi.c
+++ b/C/absmi.c
@@ -10,8 +10,11 @@
 *									 *
 * File:		absmi.c							 *
 * comments:	Portable abstract machine interpreter                    *
-* Last rev:     $Date: 2004-07-03 03:29:24 $,$Author: vsc $						 *
+* Last rev:     $Date: 2004-07-22 21:32:20 $,$Author: vsc $						 *
 * $Log: not supported by cvs2svn $
+* Revision 1.139  2004/07/03 03:29:24  vsc
+* make it compile again on non-linux machines
+*
 * Revision 1.138  2004/06/29 19:04:40  vsc
 * fix multithreaded version
 * include new version of Ricardo's profiler
@@ -384,10 +387,8 @@ Yap_absmi(int inp)
 
     noheapleft:
       saveregs();
-      if (NOfAtoms > 2*AtomHashTableSize) {
-	Yap_growatomtable();
-      } else if (!Yap_growheap(FALSE, 0, NULL)) {
-	Yap_Error(FATAL_ERROR, TermNil, "YAP failed to grow heap: %s", Yap_ErrorMessage);
+      if (!Yap_growheap(FALSE, 0, NULL)) {
+	Yap_Error(OUT_OF_HEAP_ERROR, TermNil, "YAP failed to grow heap: %s", Yap_ErrorMessage);
 	setregs();
 	FAIL();
       }
@@ -11649,8 +11650,9 @@ Yap_absmi(int inp)
 	/* setup GB */
 	WRITEBACK_Y_AS_ENV();
 	YREG[E_CB] = (CELL) B;
-	if (ActiveSignals)
+	if (ActiveSignals) {
 	  goto creep_pe;
+	}
 	saveregs_and_ycache();
 	if (!Yap_gc(((PredEntry *)SREG)->ArityOfPE, ENV, NEXTOP(PREG, sla))) {
 	  Yap_Error(OUT_OF_STACK_ERROR,TermNil,Yap_ErrorMessage);
@@ -11920,6 +11922,9 @@ Yap_absmi(int inp)
 	  }
 	}
 	if (ActiveSignals) {
+	  if (ActiveSignals & YAP_CDOVF_SIGNAL) {
+	    goto noheapleft;
+	  }
 	  goto creep;
 	}
 	saveregs();
diff --git a/C/alloc.c b/C/alloc.c
index 64adc1036..2a4a14fa7 100644
--- a/C/alloc.c
+++ b/C/alloc.c
@@ -12,7 +12,7 @@
 * Last rev:								 *
 * mods:									 *
 * comments:	allocating space					 *
-* version:$Id: alloc.c,v 1.51 2004-06-23 17:24:19 vsc Exp $		 *
+* version:$Id: alloc.c,v 1.52 2004-07-22 21:32:20 vsc Exp $		 *
 *************************************************************************/
 #ifdef SCCS
 static char SccsId[] = "%W% %G%";
@@ -881,11 +881,8 @@ ExtendWorkSpace(Int s, int fixed_allocation)
       return FALSE;
     }
   } else if (a < WorkSpaceTop) {
-      Yap_ErrorMessage = Yap_ErrorSay;
-      snprintf5(Yap_ErrorMessage, MAX_ERROR_MSG_SIZE,
-		"mmap could grew memory at lower addresses than %p, got %p", WorkSpaceTop, a );
-      Yap_PrologMode = OldPrologMode;
-      return FALSE;
+    /* try again */
+    return ExtendWorkSpace(s, fixed_allocation);
   }
   WorkSpaceTop = (char *) a + s;
   Yap_PrologMode = OldPrologMode;
diff --git a/C/c_interface.c b/C/c_interface.c
index 3e37051ec..5bfe85280 100644
--- a/C/c_interface.c
+++ b/C/c_interface.c
@@ -10,8 +10,15 @@
 * File:		c_interface.c						 *
 * comments:	c_interface primitives definition 			 *
 *									 *
-* Last rev:	$Date: 2004-06-29 19:04:41 $,$Author: vsc $						 *
+* Last rev:	$Date: 2004-07-22 21:32:20 $,$Author: vsc $						 *
 * $Log: not supported by cvs2svn $
+* Revision 1.50  2004/06/29 19:04:41  vsc
+* fix multithreaded version
+* include new version of Ricardo's profiler
+* new predicat atomic_concat
+* allow multithreaded-debugging
+* small fixes
+*
 * Revision 1.49  2004/06/09 03:32:02  vsc
 * fix bugs
 *
@@ -50,6 +57,7 @@
 #ifdef YAPOR
 #include "or.macros.h"
 #endif	/* YAPOR */
+#include "threads.h"
 
 #define YAP_BOOT_FROM_PROLOG       0
 #define YAP_BOOT_FROM_SAVED_CODE   1
@@ -146,6 +154,11 @@ X_API void    STD_PROTO(YAP_UserCPredicate,(char *,CPredicate,unsigned long int)
 X_API void    STD_PROTO(YAP_UserBackCPredicate,(char *,CPredicate,CPredicate,unsigned long int,unsigned int));
 X_API void    STD_PROTO(YAP_UserCPredicateWithArgs,(char *,CPredicate,unsigned long int,Term));
 X_API Int     STD_PROTO(YAP_CurrentModule,(void));
+X_API int     STD_PROTO(YAP_ThreadSelf,(void));
+X_API int     STD_PROTO(YAP_ThreadCreateEngine,(thread_attr *));
+X_API int     STD_PROTO(YAP_ThreadAttachEngine,(int));
+X_API int     STD_PROTO(YAP_ThreadDetachEngine,(int));
+X_API int     STD_PROTO(YAP_ThreadDestroyEngine,(int));
 
 static int (*do_getf)(void);
 
@@ -1240,3 +1253,53 @@ YAP_CurrentModule(void)
   return(CurrentModule);
 } 
 
+X_API int
+YAP_ThreadSelf(void)
+{
+#if USE_THREADS
+  return Yap_thread_self();
+#else
+  return 0;
+#endif
+} 
+
+X_API int
+YAP_ThreadCreateEngine(thread_attr *attr)
+{
+#if USE_THREADS
+  return Yap_thread_create_engine(attr);
+#else
+  return FALSE;
+#endif
+} 
+
+X_API int
+YAP_ThreadAttachEngine(int wid)
+{
+#if USE_THREADS
+  return Yap_thread_attach_engine(wid);
+#else
+  return FALSE;
+#endif
+} 
+
+X_API int
+YAP_ThreadDetachEngine(int wid)
+{
+#if USE_THREADS
+  return Yap_thread_detach_engine(wid);
+#else
+  return FALSE;
+#endif
+} 
+
+X_API int
+YAP_ThreadDestroyEngine(int wid)
+{
+#if USE_THREADS
+  return Yap_thread_destroy_engine(wid);
+#else
+  return FALSE;
+#endif
+} 
+
diff --git a/C/cdmgr.c b/C/cdmgr.c
index d899bbb34..607b77dfe 100644
--- a/C/cdmgr.c
+++ b/C/cdmgr.c
@@ -11,8 +11,15 @@
 * File:		cdmgr.c							 *
 * comments:	Code manager						 *
 *									 *
-* Last rev:     $Date: 2004-06-29 19:04:41 $,$Author: vsc $						 *
+* Last rev:     $Date: 2004-07-22 21:32:20 $,$Author: vsc $						 *
 * $Log: not supported by cvs2svn $
+* Revision 1.125  2004/06/29 19:04:41  vsc
+* fix multithreaded version
+* include new version of Ricardo's profiler
+* new predicat atomic_concat
+* allow multithreaded-debugging
+* small fixes
+*
 * Revision 1.124  2004/06/05 03:36:59  vsc
 * coroutining is now a part of attvars.
 * some more fixes.
@@ -3254,15 +3261,27 @@ fetch_next_lu_clause(PredEntry *pe, yamop *i_code, Term th, Term tb, Term tr, ya
 
     while ((t = Yap_FetchTermFromDB(cl->ClSource)) == 0L) {
       if (first_time) {
-	if (!Yap_gc(4, YENV, P)) {
+	ARG5 = th;
+	ARG6 = tb;
+	ARG7 = tr;
+	if (!Yap_gc(7, YENV, P)) {
 	  Yap_Error(OUT_OF_STACK_ERROR, TermNil, Yap_ErrorMessage);
 	  return FALSE;
 	}
+	th = ARG5;
+	tb = ARG6;
+	tr = ARG7;
       } else {
-	if (!Yap_gc(5, ENV, CP)) {
+	ARG6 = th;
+	ARG7 = tb;
+	ARG8 = tr;
+	if (!Yap_gc(8, ENV, CP)) {
 	  Yap_Error(OUT_OF_STACK_ERROR, TermNil, Yap_ErrorMessage);
 	  return FALSE;
 	}
+	th = ARG6;
+	tb = ARG7;
+	tr = ARG8;
       }
     }
     return(Yap_unify(th, ArgOfTerm(1,t)) &&
diff --git a/C/exec.c b/C/exec.c
index 772cc9c25..46f723935 100644
--- a/C/exec.c
+++ b/C/exec.c
@@ -211,7 +211,7 @@ EnterCreepMode(Term t, Term mod) {
   if (ActiveSignals & YAP_CDOVF_SIGNAL) {
     ARG1 = t;
     if (!Yap_growheap(FALSE, 0, NULL)) {
-      Yap_Error(FATAL_ERROR, TermNil, "YAP failed to grow heap at meta-call");
+      Yap_Error(OUT_OF_HEAP_ERROR, TermNil, "YAP failed to grow heap at meta-call");
     }
     if (!ActiveSignals) {
       return do_execute(ARG1, mod);
diff --git a/C/grow.c b/C/grow.c
index f221a9fe6..8d50d4f19 100644
--- a/C/grow.c
+++ b/C/grow.c
@@ -730,12 +730,87 @@ do_growheap(int fix_code, UInt in_size, struct intermediates *cip)
   return FALSE;
 }
 
+static int
+growatomtable(void)
+{
+  AtomHashEntry *ntb;
+  UInt nsize = 4*AtomHashTableSize-1, i;
+  UInt start_growth_time = Yap_cputime(), growth_time;
+  int gc_verbose = Yap_is_gc_verbose();
+
+  LOCK(SignalLock);
+  if (ActiveSignals == YAP_CDOVF_SIGNAL) {
+    CreepFlag = CalculateStackGap();
+  }
+  ActiveSignals &= ~YAP_CDOVF_SIGNAL;
+  UNLOCK(SignalLock);
+  while ((ntb = (AtomHashEntry *)Yap_AllocCodeSpace(nsize*sizeof(AtomHashEntry))) == NULL) {
+    /* leave for next time */
+    if (!do_growheap(FALSE, nsize*sizeof(AtomHashEntry), NULL))
+      return FALSE;
+  }
+  atom_table_overflows++;
+  if (gc_verbose) {
+    fprintf(Yap_stderr, "%% Atom Table overflow %d\n", atom_table_overflows);
+    fprintf(Yap_stderr, "%%    growing the atom table to %ld entries\n", (long int)(nsize));
+  }
+  YAPEnterCriticalSection();
+  for (i = 0; i < nsize; ++i) {
+    INIT_RWLOCK(ntb[i].AERWLock);
+    ntb[i].Entry = NIL;
+  }
+  for (i = 0; i < AtomHashTableSize; i++) {
+    Atom            catom;
+
+    READ_LOCK(HashChain[i].AERWLock);
+    catom = HashChain[i].Entry;
+    while (catom != NIL) {
+      AtomEntry *ap = RepAtom(catom);
+      Atom natom;
+      CELL hash;
+
+      hash = HashFunction(ap->StrOfAE) % nsize;
+      natom = ap->NextOfAE;
+      ap->NextOfAE = ntb[hash].Entry;
+      ntb[hash].Entry = catom;
+      catom = natom;
+    }
+    READ_UNLOCK(HashChain[i].AERWLock);
+  }
+  Yap_FreeCodeSpace((char *)HashChain);
+  HashChain = ntb;
+  AtomHashTableSize = nsize;
+  YAPLeaveCriticalSection();
+  growth_time = Yap_cputime()-start_growth_time;
+  total_atom_table_overflow_time += growth_time;
+  if (gc_verbose) {
+    fprintf(Yap_stderr, "%%   took %g sec\n", (double)growth_time/1000);
+    fprintf(Yap_stderr, "%% Total of %g sec expanding atom table \n", (double)total_atom_table_overflow_time/1000);
+  }
+  if (HeapTop + sizeof(YAP_SEG_SIZE) < HeapLim) {
+    /* make sure there is no heap overflow */
+    int res;
+    YAPEnterCriticalSection();
+    res = do_growheap(FALSE, 0, NULL);
+    YAPLeaveCriticalSection();
+    return res;
+  } else {
+    return TRUE;
+  }
+}
+
+
 int
 Yap_growheap(int fix_code, UInt in_size, void *cip)
 {
   int res;
 
   Yap_PrologMode |= GrowHeapMode;
+  if (NOfAtoms > 2*AtomHashTableSize) {
+      res  = growatomtable();
+      Yap_PrologMode &= ~GrowHeapMode;
+      return res;
+  }
   res=do_growheap(fix_code, in_size, (struct intermediates *)cip);
   Yap_PrologMode &= ~GrowHeapMode;
   return res;
@@ -1065,66 +1140,6 @@ Yap_shift_visit(CELL **to_visit, CELL ***to_visit_maxp)
 #endif
 }
 
-void
-Yap_growatomtable(void)
-{
-  AtomHashEntry *ntb;
-  UInt nsize = 4*AtomHashTableSize-1, i;
-  UInt start_growth_time = Yap_cputime(), growth_time;
-  int gc_verbose = Yap_is_gc_verbose();
-
-  LOCK(SignalLock);
-  if (ActiveSignals == YAP_CDOVF_SIGNAL) {
-    CreepFlag = CalculateStackGap();
-  }
-  ActiveSignals &= ~YAP_CDOVF_SIGNAL;
-  UNLOCK(SignalLock);
-  while ((ntb = (AtomHashEntry *)Yap_AllocCodeSpace(nsize*sizeof(AtomHashEntry))) == NULL) {
-    /* leave for next time */
-    if (!do_growheap(FALSE, nsize*sizeof(AtomHashEntry), NULL))
-      return;
-  }
-  atom_table_overflows++;
-  if (gc_verbose) {
-    fprintf(Yap_stderr, "%% Atom Table overflow %d\n", atom_table_overflows);
-    fprintf(Yap_stderr, "%%    growing the atom table to %ld entries\n", (long int)(nsize));
-  }
-  YAPEnterCriticalSection();
-  for (i = 0; i < nsize; ++i) {
-    INIT_RWLOCK(ntb[i].AERWLock);
-    ntb[i].Entry = NIL;
-  }
-  for (i = 0; i < AtomHashTableSize; i++) {
-    Atom            catom;
-
-    READ_LOCK(HashChain[i].AERWLock);
-    catom = HashChain[i].Entry;
-    while (catom != NIL) {
-      AtomEntry *ap = RepAtom(catom);
-      Atom natom;
-      CELL hash;
-
-      hash = HashFunction(ap->StrOfAE) % nsize;
-      natom = ap->NextOfAE;
-      ap->NextOfAE = ntb[hash].Entry;
-      ntb[hash].Entry = catom;
-      catom = natom;
-    }
-    READ_UNLOCK(HashChain[i].AERWLock);
-  }
-  Yap_FreeCodeSpace((char *)HashChain);
-  HashChain = ntb;
-  AtomHashTableSize = nsize;
-  YAPLeaveCriticalSection();
-  growth_time = Yap_cputime()-start_growth_time;
-  total_atom_table_overflow_time += growth_time;
-  if (gc_verbose) {
-    fprintf(Yap_stderr, "%%   took %g sec\n", (double)growth_time/1000);
-    fprintf(Yap_stderr, "%% Total of %g sec expanding atom table \n", (double)total_atom_table_overflow_time/1000);
-  }
-}
-
-
 static Int
 p_inform_trail_overflows(void)
 {
diff --git a/C/iopreds.c b/C/iopreds.c
index 60e2cac8e..d3b6bf351 100644
--- a/C/iopreds.c
+++ b/C/iopreds.c
@@ -3729,7 +3729,10 @@ format_has_tabs(const char *seq)
   while ((ch = *seq++)) {
     if (ch == '~') {
       ch = *seq++;
-      if (ch == 't') {
+      if (ch == '*') {
+	ch = *seq++;
+      }
+      if (ch == 't' || ch == '|') {
 	return TRUE;
       }
     }
@@ -3797,19 +3800,20 @@ format(Term tail, Term args, int sno)
     tnum = 0;
     targs = mytargs;
   }
-  format_base = format_ptr = Yap_AllocAtomSpace(FORMAT_MAX_SIZE*sizeof(char));
-  format_max = format_base+FORMAT_MAX_SIZE;
-  if (format_ptr == NULL) {
-    Yap_Error(INSTANTIATION_ERROR,tail,"format/2");
-    return(FALSE);
-  }  
-  format_buf_size = FORMAT_MAX_SIZE;
   format_error = FALSE;
 
   if ((has_tabs = format_has_tabs(fptr))) {
+    format_base = format_ptr = Yap_AllocAtomSpace(FORMAT_MAX_SIZE*sizeof(char));
+    format_max = format_base+FORMAT_MAX_SIZE;
+    if (format_ptr == NULL) {
+      Yap_Error(INSTANTIATION_ERROR,tail,"format/2");
+      return(FALSE);
+    }  
+    format_buf_size = FORMAT_MAX_SIZE;
     f_putc = format_putc;
   } else {
     f_putc = Stream[sno].stream_putc;
+    format_base = NULL;
   }
   while ((ch = *fptr++)) {
     Term t = TermNil;
@@ -4179,7 +4183,7 @@ format(Term tail, Term args, int sno)
 
 static Int
 p_format(void)
-{				/* '$format'(Control,Args)               */
+{				/* 'format'(Control,Args)               */
   Int res;
   LOCK(BGL);
   res = format(Deref(ARG1),Deref(ARG2), Yap_c_output_stream);
@@ -4190,7 +4194,7 @@ p_format(void)
 
 static Int
 p_format2(void)
-{				/* '$format'(Stream,Control,Args)          */
+{				/* 'format'(Stream,Control,Args)          */
   int old_c_stream = Yap_c_output_stream;
   Int out;
 
@@ -4789,8 +4793,8 @@ Yap_InitIOPreds(void)
   Yap_InitCPred ("$skip", 2, p_skip, SafePredFlag|SyncPredFlag);
   Yap_InitCPred ("$write", 2, p_write, SyncPredFlag);
   Yap_InitCPred ("$write", 3, p_write2, SyncPredFlag);
-  Yap_InitCPred ("$format", 2, p_format, SyncPredFlag);
-  Yap_InitCPred ("$format", 3, p_format2, SyncPredFlag);
+  Yap_InitCPred ("format", 2, p_format, SyncPredFlag);
+  Yap_InitCPred ("format", 3, p_format2, SyncPredFlag);
   Yap_InitCPred ("$current_line_number", 2, p_cur_line_no, SafePredFlag|SyncPredFlag);
   Yap_InitCPred ("$line_position", 2, p_line_position, SafePredFlag|SyncPredFlag);
   Yap_InitCPred ("$character_count", 2, p_character_count, SafePredFlag|SyncPredFlag);
diff --git a/C/threads.c b/C/threads.c
index 6cc31a771..e98996218 100644
--- a/C/threads.c
+++ b/C/threads.c
@@ -30,6 +30,8 @@ static char     SccsId[] = "%W% %G%";
 
 #if THREADS
 
+#include "threads.h"
+
 /*
  * This file includes the definition of threads in Yap. Threads
  * are supposed to be compatible with the SWI-Prolog thread package.
@@ -70,10 +72,30 @@ store_specs(int new_worker_id, UInt ssize, UInt tsize, Term tgoal, Term tdetach)
 }
 
 
+static void
+kill_thread_engine (int wid)
+{
+  Prop p0 = AbsPredProp(heap_regs->thread_handle[wid].local_preds);
+  /* kill all thread local preds */
+  while(p0) {
+    PredEntry *ap = RepPredProp(p0);
+    p0 = ap->NextOfPE;
+    Yap_Abolish(ap);
+    Yap_FreeCodeSpace((char *)ap);
+  }
+  Yap_KillStacks(wid);
+  heap_regs->wl[wid].active_signals = 0L;
+  free(heap_regs->wl[wid].scratchpad.ptr);
+  free(ThreadHandle[wid].default_yaam_regs);
+  free(ThreadHandle[wid].start_of_timesp);
+  free(ThreadHandle[wid].last_timep);
+  ThreadHandle[wid].in_use = FALSE;
+  pthread_mutex_destroy(&(ThreadHandle[wid].tlock));
+}
+
 static void
 thread_die(int wid, int always_die)
 {
-  Prop p0;
 
   LOCK(ThreadHandlesLock);
   if (!always_die) {
@@ -81,50 +103,49 @@ thread_die(int wid, int always_die)
     ThreadsTotalTime += Yap_cputime();
   }
   if (ThreadHandle[wid].tdetach == MkAtomTerm(AtomTrue) ||
-      always_die) {
-    p0 = AbsPredProp(heap_regs->thread_handle[wid].local_preds);
-    /* kill all thread local preds */
-    while(p0) {
-      PredEntry *ap = RepPredProp(p0);
-      p0 = ap->NextOfPE;
-      Yap_Abolish(ap);
-      Yap_FreeCodeSpace((char *)ap);
-    }
-    Yap_KillStacks(wid);
-    heap_regs->wl[wid].active_signals = 0L;
-    heap_regs->wl[wid].active_signals = 0L;
-    free(heap_regs->wl[wid].scratchpad.ptr);
-    free(ThreadHandle[wid].default_yaam_regs);
-    free(ThreadHandle[wid].start_of_timesp);
-    free(ThreadHandle[wid].last_timep);
-    ThreadHandle[wid].in_use = FALSE;
-    pthread_mutex_destroy(&(ThreadHandle[wid].tlock));
-  }
+      always_die)
+    kill_thread_engine(wid);
   UNLOCK(ThreadHandlesLock);
 }
 
+static void
+setup_engine(int myworker_id)
+{
+  REGSTORE *standard_regs = (REGSTORE *)malloc(sizeof(REGSTORE));
+  int oldworker_id = worker_id;
+  
+  /* create the YAAM descriptor */
+  ThreadHandle[myworker_id].default_yaam_regs = standard_regs;
+  pthread_setspecific(Yap_yaamregs_key, (void *)standard_regs);
+  Yap_InitExStacks(ThreadHandle[myworker_id].ssize, ThreadHandle[myworker_id].tsize);
+  CurrentModule = ThreadHandle[myworker_id].cmod;
+  worker_id = myworker_id;
+  Yap_InitTime();
+  Yap_InitYaamRegs();
+  worker_id = oldworker_id;
+  {
+    Yap_ReleasePreAllocCodeSpace(Yap_PreAllocCodeSpace());
+  }
+  /* I exist */
+  NOfThreadsCreated++;
+}
+
+static void
+start_thread(int myworker_id)
+{
+  setup_engine(myworker_id);
+  worker_id = myworker_id;
+}
+
 static void *
 thread_run(void *widp)
 {
   Term tgoal;
   Term tgs[2];
   int out;
-  REGSTORE *standard_regs = (REGSTORE *)malloc(sizeof(REGSTORE));
   int myworker_id = *((int *)widp); 
-  
-  /* create the YAAM descriptor */
-  ThreadHandle[myworker_id].default_yaam_regs = standard_regs;
-  pthread_setspecific(Yap_yaamregs_key, (void *)standard_regs);
-  worker_id = myworker_id;
-  /* I exist */
-  NOfThreadsCreated++;
-  Yap_InitExStacks(ThreadHandle[myworker_id].ssize, ThreadHandle[myworker_id].tsize);
-  CurrentModule = ThreadHandle[myworker_id].cmod;
-  Yap_InitTime();
-  Yap_InitYaamRegs();
-  {
-    Yap_ReleasePreAllocCodeSpace(Yap_PreAllocCodeSpace());
-  }
+
+  start_thread(myworker_id);
   tgs[0] = Yap_FetchTermFromDB(ThreadHandle[worker_id].tgoal);
   tgs[1] = ThreadHandle[worker_id].tdetach;
   tgoal = Yap_MkApplTerm(FunctorThreadRun, 2, tgs);
@@ -139,6 +160,13 @@ p_thread_new_tid(void)
   return Yap_unify(MkIntegerTerm(allocate_new_tid()), ARG1);
 }
 
+static void
+init_thread_engine(int new_worker_id, UInt ssize, UInt tsize, Term tgoal, Term tdetach)
+{
+  store_specs(new_worker_id, ssize, tsize, tgoal, tdetach);
+  pthread_mutex_init(&ThreadHandle[new_worker_id].tlock, NULL);
+}
+
 static Int
 p_create_thread(void)
 {
@@ -153,33 +181,9 @@ p_create_thread(void)
     /* YAP ERROR */
     return FALSE;
   }
+  init_thread_engine(new_worker_id, ssize, tsize, tgoal, tdetach);
   ThreadHandle[new_worker_id].id = new_worker_id;
-  store_specs(new_worker_id, ssize, tsize, tgoal, tdetach);
-  pthread_mutex_init(&ThreadHandle[new_worker_id].tlock, NULL);
-  if ((ThreadHandle[new_worker_id].ret = pthread_create(&ThreadHandle[new_worker_id].handle, NULL, thread_run, (void *)(&(ThreadHandle[new_worker_id].id)))) == 0) {
-    return TRUE;
-  }
-  /* YAP ERROR */
-  return FALSE;
-}
-
-static Int
-Yap_new_thread(void)
-{
-  UInt ssize = IntegerOfTerm(Deref(ARG2));
-  UInt tsize = IntegerOfTerm(Deref(ARG3));
-  /*  UInt systemsize = IntegerOfTerm(Deref(ARG4)); */
-  Term tgoal = Deref(ARG1);
-  Term tdetach = Deref(ARG5);
-  int new_worker_id = IntegerOfTerm(Deref(ARG6));
-  
-  if (new_worker_id == -1) {
-    /* YAP ERROR */
-    return FALSE;
-  }
-  ThreadHandle[new_worker_id].id = new_worker_id;
-  store_specs(new_worker_id, ssize, tsize, tgoal, tdetach);
-  pthread_mutex_init(&ThreadHandle[new_worker_id].tlock, NULL);
+  ThreadHandle[new_worker_id].ref_count = 1;
   if ((ThreadHandle[new_worker_id].ret = pthread_create(&ThreadHandle[new_worker_id].handle, NULL, thread_run, (void *)(&(ThreadHandle[new_worker_id].id)))) == 0) {
     return TRUE;
   }
@@ -194,11 +198,62 @@ p_thread_self(void)
 }
 
 int
-Yap_self(void)
+Yap_thread_self(void)
 {
   return worker_id;
 }
 
+int
+Yap_thread_create_engine(thread_attr *ops)
+{
+  int new_id = allocate_new_tid();
+  if (new_id == -1) {
+    /* YAP ERROR */
+    return FALSE;
+  }
+  init_thread_engine(new_id, ops->ssize, ops->tsize, TermNil, TermNil);
+  ThreadHandle[new_id].id = new_id;
+  ThreadHandle[new_id].handle = pthread_self();
+  ThreadHandle[new_id].ref_count = 0;
+  setup_engine(new_id);
+  return TRUE;
+}
+
+int
+Yap_thread_attach_engine(int wid)
+{
+  pthread_mutex_lock(&(ThreadHandle[wid].tlock));
+  ThreadHandle[wid].handle = pthread_self();
+  ThreadHandle[wid].ref_count++;
+  worker_id = wid;
+  pthread_mutex_unlock(&(ThreadHandle[wid].tlock));
+  return TRUE;
+}
+
+int
+Yap_thread_detach_engine(int wid)
+{
+  pthread_mutex_lock(&(ThreadHandle[wid].tlock));
+  ThreadHandle[wid].handle = 0;
+  ThreadHandle[wid].ref_count--;
+  pthread_mutex_unlock(&(ThreadHandle[wid].tlock));
+  return TRUE;
+}
+
+int
+Yap_thread_destroy_engine(int wid)
+{
+  pthread_mutex_lock(&(ThreadHandle[wid].tlock));
+  if (ThreadHandle[wid].ref_count == 0) {
+    pthread_mutex_unlock(&(ThreadHandle[wid].tlock));
+    kill_thread_engine(wid);
+    return TRUE;
+  } else {
+    pthread_mutex_unlock(&(ThreadHandle[wid].tlock));
+    return FALSE;
+  }
+}
+
 static Int
 p_thread_join(void)
 {
diff --git a/CLPBN/clpbn.yap b/CLPBN/clpbn.yap
index a717ac29c..5e498d659 100644
--- a/CLPBN/clpbn.yap
+++ b/CLPBN/clpbn.yap
@@ -1,16 +1,11 @@
 
 
-:- module(clpbn, [{}/1,
-	clpbn_findall/3,
-	clpbn_setof/3]).
+:- module(clpbn, [{}/1).
 
 :- use_module(library(atts)).
 :- use_module(library(lists)).
 :- use_module(library(terms)).
 
-:- op(1200, xfx, '<--').
-:- op(1200,  fx, '<--').
-:- op( 500, xfx, '=>').
 :- op( 500, xfy, with).
 
 %
@@ -40,15 +35,13 @@
 			 execute_pre_evidence/0
 		    ]).
 
-:- include('clpbn/aggs').
-
 use(vel).
 
 {Var = Key with Dist} :-
 %	key_entry(Key,Indx),
 %	array_element(clpbn,Indx,El),
 %	attributes:put_att(El,3,indx(Indx)),
-	clpbn:put_atts(El,[key(Key),dist(E=>Domain)]),
+	put_atts(El,[key(Key),dist(E=>Domain)]),
 	extract_dist(Dist, E, Domain),
 	add_evidence(Var,El).
 
@@ -257,25 +250,6 @@ starter_vars([Var|Vs]) :-
 	starter_vars(Vs).
 
 
-/* attribute_goal(Var, Goal) :-
-	get_atts(Var, [key(_)]),
-	get_bnode(Var, Goal).
-	
-	get_value(clpbn_key, Max),
-	Max1 is Max-1,
-	run_through_array(0, Max1, Goal).
-
-
-run_through_array(Max,Max,Goal) :- !,
-	array_element(clpbn, Max, V),
-	get_bnode(V, Goal).
-run_through_array(I,Max,(G,Goal)) :- !,
-	array_element(clpbn, I, V),
-	get_bnode(V, G),
-	I1 is I+1,
-	run_through_array(I1,Max,Goal).
-*/
-
 get_bnode(Var, Goal) :-
 	get_atts(Var, [key(Key),dist(X)]),
 	dist_goal(X, Key, Goal0),
diff --git a/H/Heap.h b/H/Heap.h
index 7e6e7fe10..f36764f33 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 1.63 2004-07-15 15:47:08 vsc Exp $	 *
+* version:      $Id: Heap.h,v 1.64 2004-07-22 21:32:21 vsc Exp $	 *
 *************************************************************************/
 
 /* information that can be stored in Code Space */
@@ -76,6 +76,7 @@ typedef struct thandle {
   REGSTORE *current_yaam_regs;
   struct pred_entry *local_preds;
   pthread_t handle;
+  int ref_count;
   pthread_mutex_t tlock;
 #if HAVE_GETRUSAGE
   struct timeval *start_of_timesp;
diff --git a/H/Yapproto.h b/H/Yapproto.h
index 96e91e171..a1cf73317 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 1.52 2004-06-05 03:37:00 vsc Exp $	 *
+* version:      $Id: Yapproto.h,v 1.53 2004-07-22 21:32:21 vsc Exp $	 *
 *************************************************************************/
 
 /* prototype file for Yap */
@@ -162,7 +162,6 @@ int     STD_PROTO(Yap_growheap,      (int, UInt, void *));
 int     STD_PROTO(Yap_growstack,     (long));
 int     STD_PROTO(Yap_growtrail,     (long));
 int     STD_PROTO(Yap_growglobal,    (CELL **));
-void    STD_PROTO(Yap_growatomtable, (void));
 CELL  **STD_PROTO(Yap_shift_visit,   (CELL **, CELL ***));
 
 /* heapgc.c */
diff --git a/H/absmi.h b/H/absmi.h
index f8a19f1ca..7d3c59c66 100644
--- a/H/absmi.h
+++ b/H/absmi.h
@@ -695,7 +695,7 @@ Macros to check the limits of stacks
        (GLOB) > H_FZ && (GLOB) < (CELL *)B_FZ) goto Label
 #else
 #define check_stack(Label, GLOB)                             \
- if ( (Int)(Unsigned(E_YREG) - CFREG) < (Int)(GLOB) ) goto Label
+ if ( (Int)(Unsigned(E_YREG) - Unsigned(GLOB)) < CFREG ) goto Label
 #endif /* SBA && YAPOR */
 
 /***************************************************************
diff --git a/include/YapInterface.h b/include/YapInterface.h
index 957b40a59..e2979a2e2 100644
--- a/include/YapInterface.h
+++ b/include/YapInterface.h
@@ -339,9 +339,15 @@ extern X_API void  *PROTO(YAP_Predicate,(YAP_Atom,unsigned long int,int));
 /*  int  YAP_Predicate()  */
 extern X_API void  PROTO(YAP_PredicateInfo,(void *,YAP_Atom *,unsigned long int*,int*));
 
-/*  int  YAP_Predicate()  */
+/*  int  YAP_CurrentModule()  */
 extern X_API int  PROTO(YAP_CurrentModule,(void));
 
+extern X_API int PROTO(YAP_ThreadSelf,(void));
+extern X_API int PROTO(YAP_ThreadCreateEngine,(YAP_thread_attr *));
+extern X_API int PROTO(YAP_ThreadAttachEngine,(int));
+extern X_API int PROTO(YAP_ThreadDetachEngine,(int));
+extern X_API int PROTO(YAP_ThreadDestroyEngine,(int));
+
 #define YAP_InitCPred(N,A,F)  YAP_UserCPredicate(N,F,A)
 
 __END_DECLS
diff --git a/include/yap_structs.h b/include/yap_structs.h
index 78aaa5893..d2ac14c4d 100644
--- a/include/yap_structs.h
+++ b/include/yap_structs.h
@@ -96,3 +96,11 @@ typedef struct {
   char **Argv;
 } YAP_init_args;
 
+
+/* from thread.h */
+typedef struct {
+  unsigned long int		    ssize;
+  unsigned long int		    tsize;
+  int		   (*cancel)(int);
+} YAP_thread_attr;
+
diff --git a/library/yap2swi/yap2swi.c b/library/yap2swi/yap2swi.c
index 20492f23d..f621edc4d 100644
--- a/library/yap2swi/yap2swi.c
+++ b/library/yap2swi/yap2swi.c
@@ -1083,6 +1083,17 @@ X_API void PL_register_extensions(PL_extension *ptr)
   }
 }
 
+X_API int PL_thread_self(void)
+{
+  return YAP_ThreadSelf();
+}
+
+X_API int PL_thread_attach_engine(const PL_thread_attr_t *attr)
+{
+  /*  YAP_thread_attr yap; */
+  return YAP_ThreadSelf();
+}
+
 /* note: fprintf may be called from anywhere, so please don't try
    to be smart and allocate stack from somewhere else */
 X_API int Sprintf(char *format,...)
diff --git a/library/yap2swi/yap2swi.h b/library/yap2swi/yap2swi.h
index 9409fe3b7..95258a5ee 100644
--- a/library/yap2swi/yap2swi.h
+++ b/library/yap2swi/yap2swi.h
@@ -39,6 +39,17 @@ typedef struct _PL_extension
   short		flags;			/* Or of PL_FA_... */
 } PL_extension;
 
+typedef struct
+{ unsigned long	    local_size;		/* Stack sizes */
+  unsigned long	    global_size;
+  unsigned long	    trail_size;
+  unsigned long	    argument_size;
+  char *	    alias;		/* alias name */
+  int		  (*cancel)(int id);	/* cancel function */
+  void *	    reserved[5];	/* reserved for extensions */
+} PL_thread_attr_t;
+
+
 #define PL_FA_NOTRACE		(0x01)	/* foreign cannot be traced */
 #define PL_FA_TRANSPARENT	(0x02)	/* foreign is module transparent */
 #define PL_FA_NONDETERMINISTIC	(0x04)	/* foreign is non-deterministic */
@@ -181,6 +192,8 @@ extern X_API term_t PL_exception(qid_t);
 extern X_API int PL_call_predicate(module_t, int, predicate_t, term_t);
 extern X_API int PL_call(term_t, module_t);
 extern X_API void PL_register_extensions(PL_extension *);
+extern X_API int  PL_thread_self(void);
+extern X_API int PL_thread_attach_engine(const PL_thread_attr_t *);
 
 
 extern X_API int Sprintf(char *,...);
diff --git a/misc/yap.def b/misc/yap.def
index 191b43380..1f2b0b9d0 100644
--- a/misc/yap.def
+++ b/misc/yap.def
@@ -84,3 +84,8 @@ YAP_UserCPredicate
 YAP_UserBackCPredicate
 YAP_UserCPredicateWithArgs
 YAP_CurrentModule
+YAP_ThreadSelf
+YAP_ThreadCreateEngine
+YAP_ThreadAttachEngine
+YAP_ThreadDetachEngine
+YAP_ThreadDestroyEngine
diff --git a/pl/boot.yap b/pl/boot.yap
index 59558d377..53cf70f1f 100644
--- a/pl/boot.yap
+++ b/pl/boot.yap
@@ -34,7 +34,7 @@ true :- true.
 		( Module=user ->
 		    '$compile_mode'(_,0)
 		;
-		    '$format'(user_error,'[~w]~n', [Module])
+		    format(user_error,'[~w]~n', [Module])
 		),
 		'$system_catch'('$enter_top_level',Module,Error,user:'$Error'(Error)).
 
@@ -125,10 +125,10 @@ read_sig.
 	fail.
 '$enter_top_level' :-
 	( recorded('$trace',on,_) ->
-	    '$format'(user_error, '% trace~n', [])
+	    format(user_error, '% trace~n', [])
 	;
 	  recorded('$debug', on, _) ->
-	    '$format'(user_error, '% debug~n', [])
+	    format(user_error, '% debug~n', [])
 	),
 	fail.
 '$enter_top_level' :-
@@ -292,7 +292,7 @@ repeat :- '$repeat'.
 % but YAP and SICStus does.
 %
 '$process_directive'(G, _, M) :-
-	( '$do_yes_no'(G,M) -> true ; '$format'(user_error,':- ~w:~w failed.~n',[M,G]) ).
+	( '$do_yes_no'(G,M) -> true ; format(user_error,':- ~w:~w failed.~n',[M,G]) ).
 
 '$all_directives'(_:G1) :- !,
 	'$all_directives'(G1).
@@ -440,7 +440,7 @@ repeat :- '$repeat'.
 	'$extract_goal_vars_for_dump'(VL,LIV).
 
 '$write_query_answer_true'([]) :- !,
-	'$format'(user_error,'~ntrue',[]).
+	format(user_error,'~ntrue',[]).
 '$write_query_answer_true'(_).
 
 '$show_frozen'(_,_,[]) :-
@@ -461,16 +461,16 @@ repeat :- '$repeat'.
 	fail.
 '$present_answer'((?-), Answ) :-
 	get_value('$break',BL),
-	( BL \= 0 -> 	'$format'(user_error, '[~p] ',[BL]) ;
+	( BL \= 0 -> 	format(user_error, '[~p] ',[BL]) ;
 			true ),
         ( recorded('$print_options','$toplevel'(Opts),_) ->
 	   write_term(user_error,Answ,Opts) ;
-	   '$format'(user_error,'~w',[Answ])
+	   format(user_error,'~w',[Answ])
         ),
-	'$format'(user_error,'~n', []).
+	format(user_error,'~n', []).
 
 '$another' :-
-	'$format'(user_error,' ? ',[]),
+	format(user_error,' ? ',[]),
 	'$get0'(user_input,C),
 	(   C== 0'; ->  '$skip'(user_input,10),
 	    '$add_nl_outside_console',
@@ -478,7 +478,7 @@ repeat :- '$repeat'.
 	;
 	    C== 10 -> '$add_nl_outside_console',
 		( '$undefined'('$print_message'(_,_),prolog) -> 
-			'$format'(user_error,'yes~n', [])
+			format(user_error,'yes~n', [])
 	        ;
 		   print_message(help,yes)
 		)
@@ -491,10 +491,10 @@ repeat :- '$repeat'.
 '$add_nl_outside_console' :-
 	'$is_same_tty'(user_input, user_error), !.
 '$add_nl_outside_console' :-
-	'$format'(user_error,'~n',[]).
+	format(user_error,'~n',[]).
 
 '$ask_again_for_another' :-
-	'$format'(user_error,'Action (\";\" for more choices, <return> for exit)', []),
+	format(user_error,'Action (\";\" for more choices, <return> for exit)', []),
 	'$another'.
 
 '$write_answer'(_,_,_) :-
@@ -551,25 +551,25 @@ repeat :- '$repeat'.
 
 '$write_remaining_vars_and_goals'([]).
 '$write_remaining_vars_and_goals'([G1|LG]) :-
-	'$format'(user_error,',~n',[]),
+	format(user_error,',~n',[]),
 	'$write_goal_output'(G1),
 	'$write_remaining_vars_and_goals'(LG).
 
 '$write_goal_output'(var([V|VL])) :-
-	'$format'(user_error,'~s',[V]),
+	format(user_error,'~s',[V]),
 	'$write_output_vars'(VL).
 '$write_goal_output'(nonvar([V|VL],B)) :-
-	'$format'(user_error,'~s',[V]),
+	format(user_error,'~s',[V]),
 	'$write_output_vars'(VL),
-	'$format'(user_error,' = ', []),
+	format(user_error,' = ', []),
         ( recorded('$print_options','$toplevel'(Opts),_) ->
 	   write_term(user_error,B,Opts) ;
-	   '$format'(user_error,'~w',[B])
+	   format(user_error,'~w',[B])
         ).
 '$write_goal_output'(_-G) :-
         ( recorded('$print_options','$toplevel'(Opts),_) ->
 	   write_term(user_error,G,Opts) ;
-	   '$format'(user_error,'~w',[G])
+	   format(user_error,'~w',[G])
         ).
 
 '$name_vars_in_goals'(G, VL0, NG) :-
@@ -597,7 +597,7 @@ repeat :- '$repeat'.
 
 '$write_output_vars'([]).
 '$write_output_vars'([V|VL]) :-
-	'$format'(user_error,' = ~s',[V]),
+	format(user_error,' = ~s',[V]),
 	'$write_output_vars'(VL).
 
 call(G) :- '$execute'(G).
@@ -806,7 +806,7 @@ break :- get_value('$break',BL), NBL is BL+1,
 	get_value(spy_leap,_Leap),
 	set_value('$break',NBL),
 	current_output(OutStream), current_input(InpStream),
-	'$format'(user_error, '% Break (level ~w)~n', [NBL]),
+	format(user_error, '% Break (level ~w)~n', [NBL]),
 	'$do_live',
 	!,
 	set_value('$live','$true'),
@@ -865,7 +865,7 @@ break :- get_value('$break',BL), NBL is BL+1,
 	recorda('$initialisation','$',_),
 	( '$undefined'('$print_message'(_,_),prolog) -> 
 	    ( get_value('$verbose',on) ->
-		'$format'(user_error, '~*|% consulting ~w...~n', [LC,F])
+		format(user_error, '~*|% consulting ~w...~n', [LC,F])
 		; true )
 	;
 	    '$print_message'(informational, loading(consulting, File))
@@ -881,7 +881,7 @@ break :- get_value('$break',BL), NBL is BL+1,
 	H is heapused-H0, '$cputime'(TF,_), T is TF-T0,
 	( '$undefined'('$print_message'(_,_),prolog) -> 
 	  ( get_value('$verbose',on) ->
-	     '$format'(user_error, '~*|% ~w consulted ~w bytes in ~d msecs~n', [LC,F,H,T])
+	     format(user_error, '~*|% ~w consulted ~w bytes in ~d msecs~n', [LC,F,H,T])
 	  ;
 	     true
 	  )
diff --git a/pl/debug.yap b/pl/debug.yap
index 0a6473891..ce4cbdee5 100644
--- a/pl/debug.yap
+++ b/pl/debug.yap
@@ -417,9 +417,9 @@ debugging :-
 	        ( recorded('$debug',on, R), erase(R), fail ; true),
 		( Module\=prolog,
 		  Module\=user ->
-		    '$format'(user_error,"~a~a (~d) ~q: ~a:",[CSPY,SLL,L,P,Module])
+		    format(user_error,"~a~a (~d) ~q: ~a:",[CSPY,SLL,L,P,Module])
 		    ;
-		    '$format'(user_error,"~a~a (~d) ~q:",[CSPY,SLL,L,P])
+		    format(user_error,"~a~a (~d) ~q:",[CSPY,SLL,L,P])
 		),
 		'$debugger_write'(user_error,G),
 	        ( nonvar(R0), recordaifnot('$debug',on,_), fail ; true),
@@ -558,32 +558,28 @@ debugging :-
 	fail.
 
 % if we are in the interpreter, don't need to care about forcing a trace, do we?
-'$continue_debugging'(_) :-
-	recorded('$trace',on, _),
-	fail.
 '$continue_debugging'(no) :- !.
 '$continue_debugging'(_) :-
 	'$access_yap_flags'(10,1), !,
 	'$creep'.
-'$continue_debugging'(_) :-
-	recorded('$spy_stop', _, _).
+'$continue_debugging'(_).
 
 '$stop_debugging' :-
 	'$stop_creep'.
 
 '$action_help' :-
-	'$format'(user_error,"newline  creep       a       abort~n", []),
-	'$format'(user_error,"c        creep       e       exit~n", []),
-	'$format'(user_error,"f Goal   fail        h       help~n", []),
-	'$format'(user_error,"l        leap        r Goal  retry~n", []),
-	'$format'(user_error,"s        skip        t       fastskip~n", []),
-	'$format'(user_error,"q        quasiskip   k       quasileap~n", []),
-	'$format'(user_error,"b        break       n       no debug~n", []),
-	'$format'(user_error,"p        print       d       display~n", []),
-	'$format'(user_error,"<D       depth D     <       full term~n", []),
-	'$format'(user_error,"+        spy this    -       nospy this~n", []),
-	'$format'(user_error,"^        view subg   ^^      view using~n", []),
-	'$format'(user_error,"! g execute goal~n", []).
+	format(user_error,"newline  creep       a       abort~n", []),
+	format(user_error,"c        creep       e       exit~n", []),
+	format(user_error,"f Goal   fail        h       help~n", []),
+	format(user_error,"l        leap        r Goal  retry~n", []),
+	format(user_error,"s        skip        t       fastskip~n", []),
+	format(user_error,"q        quasiskip   k       quasileap~n", []),
+	format(user_error,"b        break       n       no debug~n", []),
+	format(user_error,"p        print       d       display~n", []),
+	format(user_error,"<D       depth D     <       full term~n", []),
+	format(user_error,"+        spy this    -       nospy this~n", []),
+	format(user_error,"^        view subg   ^^      view using~n", []),
+	format(user_error,"! g execute goal~n", []).
 	
 '$ilgl'(C) :-
 	'$print_message'(warning, trace_command(C)),
@@ -619,7 +615,7 @@ debugging :-
 	'$get_sterm_list'(L), !,
 	'$deb_get_sterm_in_g'(L,G,A),
 	recorda('$debug_sub_skel',L,_),
-	'$format'(user_error,"~n~w~n~n",[A]).
+	format(user_error,"~n~w~n~n",[A]).
 '$print_deb_sterm'(_) :- '$skipeol'(94).
 
 '$get_sterm_list'(L) :-
diff --git a/pl/errors.yap b/pl/errors.yap
index 78d34586e..b92e023e2 100644
--- a/pl/errors.yap
+++ b/pl/errors.yap
@@ -11,8 +11,15 @@
 * File:		errors.yap						 *
 * comments:	error messages for YAP					 *
 *									 *
-* Last rev:     $Date: 2004-06-23 17:24:20 $,$Author: vsc $						 *
+* Last rev:     $Date: 2004-07-22 21:32:22 $,$Author: vsc $						 *
 * $Log: not supported by cvs2svn $
+* Revision 1.53  2004/06/23 17:24:20  vsc
+* New comment-based message style
+* Fix thread support (at least don't deadlock with oneself)
+* small fixes for coroutining predicates
+* force Yap to recover space in arrays of dbrefs
+* use private predicates in debugger.
+*
 * Revision 1.52  2004/06/18 15:41:19  vsc
 * fix extraneous line in yes/no messages
 *
@@ -65,7 +72,7 @@ print_message(Level, Mss) :-
 	user:portray_message(Severity, Msg), !.
 '$print_message'(error,error(Msg,Info)) :-
 	( var(Msg) ; var(Info) ), !,
-	'$format'(user_error,'% YAP: no handler for error ~w~n', [error(Msg,Info)]).
+	format(user_error,'% YAP: no handler for error ~w~n', [error(Msg,Info)]).
 '$print_message'(error,error(syntax_error(A,B,C,D,E,F),_)) :- !,
 	'$output_error_message'(syntax_error(A,B,C,D,E,F), 'SYNTAX ERROR').
 '$print_message'(error,error(Msg,[Info|local_sp(Where,Envs,CPs)])) :-
@@ -76,94 +83,94 @@ print_message(Level, Mss) :-
 '$print_message'(error,error(Type,Where)) :-
 	'$output_error_message'(Type, Where), !.
 '$print_message'(error,Throw) :-
-	'$format'(user_error,'% YAP: no handler for error ~w~n', [Throw]).
+	format(user_error,'% YAP: no handler for error ~w~n', [Throw]).
 '$print_message'(informational,M) :-
 	( get_value('$verbose',on) ->
 	    '$do_informational_message'(M) ;
 	    true
 	).
 '$print_message'(warning,M) :-
-	'$format'(user_error, '% ', []),
+	format(user_error, '% ', []),
 	'$do_print_message'(M),
-	'$format'(user_error, '~n', []).
+	format(user_error, '~n', []).
 '$print_message'(help,M) :-
 	'$do_print_message'(M),
-	'$format'(user_error, '~n', []).
+	format(user_error, '~n', []).
 
 
 '$do_informational_message'(halt) :- !,
-	'$format'(user_error, '% YAP execution halted~n', []).
+	format(user_error, '% YAP execution halted~n', []).
 '$do_informational_message'(abort(_)) :- !,
-	'$format'(user_error, '% YAP execution aborted~n', []).
+	format(user_error, '% YAP execution aborted~n', []).
 '$do_informational_message'(loading(_,user)) :- !.
 '$do_informational_message'(loading(What,AbsoluteFileName)) :- !,
 	'$show_consult_level'(LC),
-	'$format'(user_error, '~*|% ~a ~a...~n', [LC, What, AbsoluteFileName]).
+	format(user_error, '~*|% ~a ~a...~n', [LC, What, AbsoluteFileName]).
 '$do_informational_message'(loaded(_,user,_,_,_)) :- !.
 '$do_informational_message'(loaded(What,AbsoluteFileName,Mod,Time,Space)) :- !,
 	'$show_consult_level'(LC0),
 	LC is LC0+1,
-	'$format'(user_error, '~*|% ~a ~a in module ~a, ~d msec ~d bytes~n', [LC, What, AbsoluteFileName,Mod,Time,Space]).
+	format(user_error, '~*|% ~a ~a in module ~a, ~d msec ~d bytes~n', [LC, What, AbsoluteFileName,Mod,Time,Space]).
 '$do_informational_message'(M) :-
-	'$format'(user_error,'% ', []),
+	format(user_error,'% ', []),
 	'$do_print_message'(M),
-	'$format'(user_error,'~n', []).
+	format(user_error,'~n', []).
 
 %message(loaded(Past,AbsoluteFileName,user,Msec,Bytes), Prefix, Suffix) :- !,
-'$do_print_message'('$format'(Msg, Args)) :- !,
-	'$format'(user_error,Msg,Args).
+'$do_print_message'(format(Msg, Args)) :- !,
+	format(user_error,Msg,Args).
 '$do_print_message'(breakp(bp(debugger,_,_,M:F/N,_),add,already)) :- !,
-	'$format'(user_error,'There is already a spy point on ~w:~w/~w.',
+	format(user_error,'There is already a spy point on ~w:~w/~w.',
 	[M,F,N]).	
 '$do_print_message'(breakp(bp(debugger,_,_,M:F/N,_),add,ok)) :- !,
-	'$format'(user_error,'Spy point set on ~w:~w/~w.',
+	format(user_error,'Spy point set on ~w:~w/~w.',
 	[M,F,N]).	
 '$do_print_message'(breakp(bp(debugger,_,_,M:F/N,_),remove,last)) :- !,
-	'$format'(user_error,'Spy point on ~w:~w/~w removed.',
+	format(user_error,'Spy point on ~w:~w/~w removed.',
 	[M,F,N]).
 '$do_print_message'(breakp(no,breakpoint_for,M:F/N)) :- !,
-	'$format'(user_error,'There is no spy point on ~w:~w/~w.',
+	format(user_error,'There is no spy point on ~w:~w/~w.',
 	[M,F,N]).
 '$do_print_message'(breakpoints([])) :- !,
-	'$format'(user_error,'There are no spy-points set.',
+	format(user_error,'There are no spy-points set.',
 	[M,F,N]).
 '$do_print_message'(breakpoints(L)) :- !,
-	'$format'(user_error,'Spy-points set on:', []),
+	format(user_error,'Spy-points set on:', []),
 	'$print_list_of_preds'(L).
 '$do_print_message'(debug(debug)) :- !,
-	'$format'(user_error,'Debug mode on.',[]).
+	format(user_error,'Debug mode on.',[]).
 '$do_print_message'(debug(off)) :- !,
-	'$format'(user_error,'Debug mode off.',[]).
+	format(user_error,'Debug mode off.',[]).
 '$do_print_message'(debug(trace)) :- !,
-	'$format'(user_error,'Trace mode on.',[]).
+	format(user_error,'Trace mode on.',[]).
 '$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'(leash([])) :- !,
-	'$format'(user_error,'No leashing.',
+	format(user_error,'No leashing.',
 	[M,F,N]).
 '$do_print_message'(leash([A|B])) :- !,
-	'$format'(user_error,'Leashing set to ~w.',
+	format(user_error,'Leashing set to ~w.',
 	[[A|B]]).
 '$do_print_message'(no) :- !,
-	'$format'(user_error, 'no', []).
+	format(user_error, 'no', []).
 '$do_print_message'(no_match(P)) :- !,
-	'$format'(user_error,'No matching predicate for ~w.',
+	format(user_error,'No matching predicate for ~w.',
 	[P]).
 '$do_print_message'(trace_command(C)) :- !,
-	'$format'(user_error,'Invalid trace command: ~c', [C]).
+	format(user_error,'Invalid trace command: ~c', [C]).
 '$do_print_message'(trace_help) :- !,
-	'$format'(user_error,'  Please enter a valid debugger command (h for help).', []).
+	format(user_error,'  Please enter a valid debugger command (h for help).', []).
 '$do_print_message'(version(Version)) :- !,
-	'$format'(user_error,'YAP version ~a', [Version]).
+	format(user_error,'YAP version ~a', [Version]).
 '$do_print_message'(yes) :- !,
-	'$format'(user_error, 'yes', []).
+	format(user_error, 'yes', []).
 '$do_print_message'(Messg) :-
-	'$format'(user_error,'~q',Messg).
+	format(user_error,'~q',Messg).
 
 '$print_list_of_preds'([]).
 '$print_list_of_preds'([P|L]) :-
-	'$format'(user_error,'~n      ~w',[P]),
+	format(user_error,'~n      ~w',[P]),
 	'$print_list_of_preds'(L).
 
 '$do_stack_dump'(Envs, CPs) :-
@@ -266,20 +273,20 @@ print_message(Level, Mss) :-
 
 '$say_stack_dump'([], []) :- !.
 '$say_stack_dump'(_, _) :-
-	'$format'(user_error,'% Stack dump for error:', []).
+	format(user_error,'% Stack dump for error:', []).
 	
 '$close_stack_dump'([], []) :- !.
 '$close_stack_dump'(_, _) :-
-	'$format'(user_error,'~n', []).
+	format(user_error,'~n', []).
 	
 '$show_cps'([]) :- !.
 '$show_cps'(List) :-
-	'$format'(user_error,'%  ~n   choice-points (goals with alternatives left):',[]),
+	format(user_error,'%  ~n   choice-points (goals with alternatives left):',[]),
         '$print_stack'(List).
 
 '$show_envs'([]) :- !.
 '$show_envs'(List) :-
-	'$format'(user_error,'%  ~n   environments (partially executed clauses):',[]),
+	format(user_error,'%  ~n   environments (partially executed clauses):',[]),
         '$print_stack'(List).
 
 '$prepare_loc'(Info,Where,Location) :- integer(Where), !,
@@ -289,16 +296,16 @@ print_message(Level, Mss) :-
 
 '$print_stack'([]).
 '$print_stack'([overflow]) :- !,
-	'$format'(user_error,'~n%	...',[]).
+	format(user_error,'~n%	...',[]).
 '$print_stack'([cl(Name,Arity,Mod,Clause)|List]) :-
 	'$show_goal'(Clause,Name,Arity,Mod),
 	'$print_stack'(List).
 
 '$show_goal'(-1,Name,Arity,Mod) :- !,
-	'$format'('~n%      ~a:~a/~d at indexing code',[Mod,Name,Arity]).
+	format('~n%      ~a:~a/~d at indexing code',[Mod,Name,Arity]).
 '$show_goal'(0,Name,Arity,Mod) :- !.
 '$show_goal'(I,Name,Arity,Mod) :-
-	'$format'(user_error,'~n%      ~a:~a/~d at clause ~d',[Mod,Name,Arity,I]).
+	format(user_error,'~n%      ~a:~a/~d at clause ~d',[Mod,Name,Arity,I]).
 
 '$construct_code'(-1,Name,Arity,Mod,Where,Location) :- !,
 	number_codes(Arity,ArityCode),
@@ -313,350 +320,350 @@ print_message(Level, Mss) :-
 	atom_concat([Where,' at ',Mod,':',Name,'/',ArityAtom,' (clause ',ClAtom,')'],Location).
 
 '$output_error_message'(consistency_error(Who),Where) :-
-	'$format'(user_error,'% CONSISTENCY ERROR- ~w ~w~n',
+	format(user_error,'% CONSISTENCY ERROR- ~w ~w~n',
 	[Who,Where]).
 '$output_error_message'(context_error(Goal,Who),Where) :-
-	'$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 ~w for array~n',
+	format(user_error,'% DOMAIN ERROR- ~w: invalid index ~w for array~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]).
 '$output_error_message'(domain_error(out_of_range,Value), Where) :-
-	'$format'(user_error,'% DOMAIN ERROR- ~w: expression ~w is out of range~n',
+	format(user_error,'% DOMAIN ERROR- ~w: expression ~w is out of range~n',
 	[Where,Value]).
 '$output_error_message'(domain_error(close_option,Opt), Where) :-
-	'$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: ~w is not allowed in the domain ~n',
+	format(user_error,'% DOMAIN ERROR- ~w: ~w is not allowed in the domain ~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]).
 '$output_error_message'(domain_error(predicate_spec,N), Where) :-
-	'$format'(user_error,'% DOMAIN ERROR- ~w: ~w invalid predicate specifier~n',
+	format(user_error,'% DOMAIN ERROR- ~w: ~w invalid predicate 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]).
 '$output_error_message'(domain_error(thread_create_option,Option+Opts), Where) :-
-	'$format'(user_error,'% DOMAIN ERROR- ~w: ~w not in ~w~n',
+	format(user_error,'% DOMAIN ERROR- ~w: ~w not in ~w~n',
 	[Where,Option, Opts]).
 '$output_error_message'(domain_error(time_out_spec,What), Where) :-
-	'$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]).
 '$output_error_message'(existence_error(mutex,F), W) :-
-	'$format'(user_error,'% EXISTENCE ERROR- ~w could not open mutex ~w~n',
+	format(user_error,'% EXISTENCE ERROR- ~w could not open mutex ~w~n',
 	[W,F]).
 '$output_error_message'(existence_error(queue,F), W) :-
-	'$format'(user_error,'% EXISTENCE ERROR- ~w could not open message queue ~w~n',
+	format(user_error,'% EXISTENCE ERROR- ~w could not open message queue ~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]).
 '$output_error_message'(out_of_heap_error, Where) :-
-	'$format'(user_error,'% OUT OF HEAP SPACE ERROR- ~w~n',
+	format(user_error,'% OUT OF HEAP SPACE ERROR- ~w~n',
 	[Where]).
 '$output_error_message'(out_of_stack_error, Where) :-
-	'$format'(user_error,'% OUT OF STACK SPACE ERROR- ~w~n',
+	format(user_error,'% OUT OF STACK SPACE ERROR- ~w~n',
 	[Where]).
 '$output_error_message'(out_of_trail_error, Where) :-
-	'$format'(user_error,'% OUT OF TRAIL SPACE ERROR- ~w~n',
+	format(user_error,'% OUT OF TRAIL SPACE ERROR- ~w~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]).
 '$output_error_message'(permission_error(create,mutex,P), Where) :-
-	'$format'(user_error,'% PERMISSION ERROR- ~w: cannot create mutex ~a~n',
+	format(user_error,'% PERMISSION ERROR- ~w: cannot create mutex ~a~n',
 	[Where,P]).
 '$output_error_message'(permission_error(create,queue,P), Where) :-
-	'$format'(user_error,'% PERMISSION ERROR- ~w: cannot create queue ~a~n',
+	format(user_error,'% PERMISSION ERROR- ~w: cannot create queue ~a~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]).
 '$output_error_message'(permission_error(modify,dynamic_procedure,_), Where) :-
-	'$format'(user_error,'% PERMISSION ERROR- ~w: modifying a dynamic procedure~n',
+	format(user_error,'% PERMISSION ERROR- ~w: modifying a dynamic procedure~n',
 	[Where]).
 '$output_error_message'(permission_error(modify,static_procedure,_), Where) :-
-	'$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]).
 '$output_error_message'(permission_error(module,redefined,Mod), Who) :-
-	'$format'(user_error,'% PERMISSION ERROR ~w- redefining module ~a in a different file~n',
+	format(user_error,'% PERMISSION ERROR ~w- redefining module ~a in a different file~n',
 	[Who,Mod]).
 '$output_error_message'(permission_error(open,source_sink,Stream), Where) :-
-	'$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]).
 '$output_error_message'(permission_error(unlock,mutex,P), Where) :-
-	'$format'(user_error,'% PERMISSION ERROR- ~w: cannot unlock mutex ~w~n',
+	format(user_error,'% PERMISSION ERROR- ~w: cannot unlock mutex ~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]).
 '$output_error_message'(syntax_error(G,0,Msg,[],0,0), Where) :- !,
-	'$format'(user_error,'% SYNTAX ERROR in ~w: ~a~n',[G,Msg]).
+	format(user_error,'% SYNTAX ERROR in ~w: ~a~n',[G,Msg]).
 '$output_error_message'(syntax_error(_,Position,_,Term,Pos,Start), Where) :-
-	'$format'(user_error,'% ~w ',[Where]),
+	format(user_error,'% ~w ',[Where]),
 	'$dump_syntax_error_line'(Start,Position),
 	'$dump_syntax_error_term'(10,Pos, Term),
-	'$format'(user_error,'.~n]~n',[]).
+	format(user_error,'.~n]~n',[]).
 '$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(char,W), Where) :-
-	'$format'(user_error,'% TYPE ERROR- ~w: expected char, got ~w~n',
+	format(user_error,'% TYPE ERROR- ~w: expected char, got ~w~n',
 	[Where,W]).
 '$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(unsigned_char,W), Where) :-
-	'$format'(user_error,'% TYPE ERROR- ~w: expected unsigned char, got ~w~n',
+	format(user_error,'% TYPE ERROR- ~w: expected unsigned char, got ~w~n',
 	[Where,W]).
 '$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]).
 
 
 '$dump_syntax_error_line'(Pos,_) :-
-	'$format'(user_error,'at line ~d:~n',
+	format(user_error,'at line ~d:~n',
 	[Pos]).
 
 '$dump_syntax_error_term'(0,J,L) :- !,
-	'$format'(user_error,'~n', []),
+	format(user_error,'~n', []),
 	'$dump_syntax_error_term'(10,J,L).
 '$dump_syntax_error_term'(_,0,L) :- !,
-	'$format'(user_error,'~n<==== HERE ====>~n', []),
+	format(user_error,'~n<==== HERE ====>~n', []),
 	'$dump_syntax_error_term'(10,-1,L).
 '$dump_syntax_error_term'(_,_,[]) :- !.
 '$dump_syntax_error_term'(I,J,[T-P|R]) :-
@@ -666,19 +673,19 @@ print_message(Level, Mss) :-
 	'$dump_syntax_error_term'(I1,J1,R).
 
 '$dump_error_token'(atom(A)) :- !,
-	'$format'(user_error,' ~a', [A]).
+	format(user_error,' ~a', [A]).
 '$dump_error_token'(number(N)) :- !,
-	'$format'(user_error,' ~w', [N]).
+	format(user_error,' ~w', [N]).
 '$dump_error_token'(var(_,S,_)) :- !,
-	'$format'(user_error,' ~s ', [S]).
+	format(user_error,' ~s ', [S]).
 '$dump_error_token'(string(S)) :- !,
-	'$format'(user_error,' ""~s""', [S]).
+	format(user_error,' ""~s""', [S]).
 '$dump_error_token'('(') :- !,
-	'$format'(user_error,"(", []).
+	format(user_error,"(", []).
 '$dump_error_token'(')') :- !,
-	'$format'(user_error," )", []).
+	format(user_error," )", []).
 '$dump_error_token'(',') :- !,
-	'$format'(user_error," ,", []).
+	format(user_error," ,", []).
 '$dump_error_token'(A) :-
-	'$format'(user_error," ~a", [A]).
+	format(user_error," ~a", [A]).
 
diff --git a/pl/listing.yap b/pl/listing.yap
index 23100c135..70b00141f 100644
--- a/pl/listing.yap
+++ b/pl/listing.yap
@@ -77,17 +77,17 @@ portray_clause(_).
 '$portray_clause'(Stream, (Pred :- true)) :- !,
 	'$beautify_vars'(Pred),
 	writeq(Stream, Pred),
-	'$format'(Stream, ".~n", []).
+	format(Stream, ".~n", []).
 '$portray_clause'(Stream, (Pred:-Body)) :- !,
 	'$beautify_vars'((Pred:-Body)),
 	writeq(Stream, Pred),
-	'$format'(Stream, " :-", []),
+	format(Stream, " :-", []),
 	'$write_body'(Body, 3, ',', Stream),
-	'$format'(Stream, ".~n", []).
+	format(Stream, ".~n", []).
 '$portray_clause'(Stream, Pred) :- !,
 	'$beautify_vars'(Pred),
 	writeq(Stream, Pred),
-	'$format'(Stream, ".~n", []).
+	format(Stream, ".~n", []).
 
 '$write_body'(X,I,T,Stream) :- var(X), !,
 	'$beforelit'(T,I,Stream),
@@ -99,40 +99,40 @@ portray_clause(_).
         '$write_body'(Q,I,',',Stream).
 '$write_body'((P->Q;S),I,_, Stream) :-
 	!,
-	'$format'(Stream, "~n~*c(",[I,0' ]),
+	format(Stream, "~n~*c(",[I,0' ]),
 	I1 is I+2,
 	'$write_body'(P,I1,'(',Stream),
-	'$format'(Stream, " ->",[]),
+	format(Stream, " ->",[]),
 	'$write_disj'((Q;S),I,I1,'->',Stream),
-	'$format'(Stream, "~n~*c)",[I,0' ]).
+	format(Stream, "~n~*c)",[I,0' ]).
 '$write_body'((P->Q|S),I,_,Stream) :-
 	!,
-	'$format'(Stream, "~n~*c(",[I,0' ]),
+	format(Stream, "~n~*c(",[I,0' ]),
 	I1 is I+2,
 	'$write_body'(P,I,'(',Stream),
-	'$format'(Stream, " ->",[]),
+	format(Stream, " ->",[]),
 	'$write_disj'((Q|S),I,I1,'->',Stream),
-	'$format'(Stream, "~n~*c)",[I,0' ]).
+	format(Stream, "~n~*c)",[I,0' ]).
 '$write_body'((P->Q),I,_,Stream) :-
 	!,
-	'$format'(Stream, "~n~*c(",[I,0' ]),
+	format(Stream, "~n~*c(",[I,0' ]),
 	I1 is I+2,
         '$write_body'(P,I1,'(',Stream),
-	'$format'(Stream, " ->",[]),
+	format(Stream, " ->",[]),
         '$write_body'(Q,I1,'->',Stream),
-	'$format'(Stream, "~n~*c)",[I,0' ]).
+	format(Stream, "~n~*c)",[I,0' ]).
 '$write_body'((P;Q),I,_,Stream) :-
         !,
-	'$format'(Stream, "~n~*c(",[I,0' ]),
+	format(Stream, "~n~*c(",[I,0' ]),
 	I1 is I+2,
 	'$write_disj'((P;Q),I,I1,'->',Stream),
-	'$format'(Stream, "~n~*c)",[I,0' ]).
+	format(Stream, "~n~*c)",[I,0' ]).
 '$write_body'((P|Q),I,_,Stream) :-
         !,
-	'$format'(Stream, "~n~*c(",[I,0' ]),
+	format(Stream, "~n~*c(",[I,0' ]),
 	I1 is I+2,
 	'$write_disj'((P|Q),I,I1,'->',Stream),
-	'$format'(Stream, "~n~*c)",[I,0' ]).
+	format(Stream, "~n~*c)",[I,0' ]).
 '$write_body'(X,I,T,Stream) :-
         '$beforelit'(T,I,Stream),
         writeq(Stream,X).
@@ -140,18 +140,18 @@ portray_clause(_).
 
 '$write_disj'((Q;S),I0,I,C,Stream) :- !,
 	'$write_body'(Q,I,C,Stream),
-	'$format'(Stream, "~n~*c;",[I0,0' ]),
+	format(Stream, "~n~*c;",[I0,0' ]),
 	'$write_disj'(S,I0,I,';',Stream).
 '$write_disj'((Q|S),I0,I,C,Stream) :- !,
 	'$write_body'(Q,I,C,Stream),
-	'$format'(Stream, "~n~*c|",[I0,0' ]),
+	format(Stream, "~n~*c|",[I0,0' ]),
 	'$write_disj'(S,I0,I,'|',Stream).
 '$write_disj'(S,I0,I,C,Stream) :-
 	'$write_body'(S,I,C,Stream).
 	
 
-'$beforelit'('(',_,Stream) :- !, '$format'(Stream," ",[]).
-'$beforelit'(_,I,Stream) :- '$format'(Stream,"~n~*c",[I,0' ]).
+'$beforelit'('(',_,Stream) :- !, format(Stream," ",[]).
+'$beforelit'(_,I,Stream) :- format(Stream,"~n~*c",[I,0' ]).
 
 '$beautify_vars'(T) :-
 	'$list_get_vars'(T,[],L),
diff --git a/pl/modules.yap b/pl/modules.yap
index 1f345fd67..17b9e0630 100644
--- a/pl/modules.yap
+++ b/pl/modules.yap
@@ -196,7 +196,7 @@ module(N) :-
 	recorda('$module','$module'(F,Mod,Exports),_).
 '$add_preexisting_module_on_file'(F,F0,Mod,Exports,R) :-
 	repeat,
-	'$format'(user_error, "The module ~a is being redefined.~n    Old file:  ~a~n    New file:  ~a~nDo you really want to redefine it? (y or n)",[Mod,F0,F]),
+	format(user_error, "The module ~a is being redefined.~n    Old file:  ~a~n    New file:  ~a~nDo you really want to redefine it? (y or n)",[Mod,F0,F]),
 	'$mod_scan'(C), !,
 	( C is "y" ->
 	    '$add_preexisting_module_on_file'(F, F, Mod, Exports, R)
@@ -227,8 +227,8 @@ module(N) :-
 
 '$check_import'(M,T,N,K) :-
     recorded('$import','$import'(M1,T,N,K),R), M1 \= M, /* ZP */ !,
-    '$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), !;
@@ -249,7 +249,7 @@ 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]),
         %            '$trace_module'(importing(M:N/K,Mod)),
 	  (Mod = user ->
              ( recordzifnot('$import','$import'(M,user,N,K),_) -> true ; true )
@@ -486,7 +486,7 @@ module(N) :-
 	'$meta_predicate'(F,Mod,N,D), !,
 	functor(G1,F,N),
 	'$meta_expansion_loop'(N,D,G,G1,HVars,MP).
-%	'$format'(user_error," gives ~w~n]",[G1]).
+%	format(user_error," gives ~w~n]",[G1]).
 
 % expand argument
 '$meta_expansion_loop'(0,_,_,_,_,_) :- !.
diff --git a/pl/statistics.yap b/pl/statistics.yap
index 15a3267f0..d569709b6 100644
--- a/pl/statistics.yap
+++ b/pl/statistics.yap
@@ -37,42 +37,42 @@ statistics :-
 
 '$statistics'(Runtime,CPUtime,Walltime,HpSpa,HpInUse,HpMax,TrlSpa, TrlInUse,_TrlMax,StkSpa, GlobInU, LocInU,GlobMax,LocMax,NOfHO,TotHOTime,NOfSO,TotSOTime,NOfTO,TotTOTime,NOfGC,TotGCTime,TotGCSize,NOfAGC,TotAGCTime,TotAGCSize) :-
 	TotalMemory is HpSpa+StkSpa+TrlSpa,
-	'$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,"~t  ~d  max~73+~n", [HpMax]),
-	'$format'(user_error,"   stack space~t~d bytes~35+", [StkSpa]),
+	format(user_error,",~t  ~d free~19+~n", [HpFree]),
+	format(user_error,"~t  ~d  max~73+~n", [HpMax]),
+	format(user_error,"   stack space~t~d bytes~35+", [StkSpa]),
 	StackInUse is GlobInU+LocInU,
-	'$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)/1000,
-	'$format'(user_error,"~n~t~3f~12+ sec. for ~w code, ~w stack, and ~w trail space overflows~n",
+	format(user_error,"~n~t~3f~12+ sec. for ~w code, ~w stack, and ~w trail space overflows~n",
 	       [OvfTime,NOfHO,NOfSO,NOfTO]),
 	TotGCTimeF is float(TotGCTime)/1000,
-	'$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",
 	       [TotGCTimeF,NOfGC,TotGCSize]),
 	TotAGCTimeF is float(TotAGCTime)/1000,
-	'$format'(user_error,"~t~3f~12+ sec. for ~w atom garbage collections which collected ~d bytes~n",
+	format(user_error,"~t~3f~12+ sec. for ~w atom garbage collections which collected ~d bytes~n",
 	       [TotAGCTimeF,NOfAGC,TotAGCSize]),
 	RTime is float(Runtime)/1000,
-	'$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'(_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_).
 
diff --git a/pl/yio.yap b/pl/yio.yap
index 5a8124df3..43b99c330 100644
--- a/pl/yio.yap
+++ b/pl/yio.yap
@@ -505,12 +505,6 @@ print(Stream,T) :-
 print(_,_).
 
 
-format(N,A) :- atom(N), !, atom_codes(N, S), '$format'(S,A).
-format(F,A) :- '$format'(F,A).
-
-format(Stream, N, A) :- atom(N), !, atom_codes(N, S), '$format'(Stream, S ,A).
-format(Stream, S, A) :- '$format'(Stream, S, A).
-
 /* interface to user portray	*/
 '$portray'(T) :-
 	\+ '$undefined'(portray(_),user),