diff --git a/C/c_interface.c b/C/c_interface.c
index 82da72fdf..6d8c8549f 100755
--- a/C/c_interface.c
+++ b/C/c_interface.c
@@ -1756,9 +1756,8 @@ X_API bool YAP_EnterGoal(YAP_PredEntryPtr ape, CELL *ptr, YAP_dogoalinfo *dgi) {
   CACHE_REGS
   PredEntry *pe = ape;
   bool out;
-  //   fprintf(stderr,"EnterGoal: H=%d ENV=%p B=%d TR=%d P=%p CP=%p
-  //   Slots=%d\n",HR-H0,LCL0-ENV,LCL0-(CELL*)B,(CELL*)TR-LCL0, P, CP,
-  //   LOCAL_CurSlot);
+     fprintf(stderr,"EnterGoal: H=%ld ENV=%ld B=%ld TR=%ld P=%p CP=%p, Slots=%ld\n",HR-H0,LCL0-ENV,LCL0-(CELL*)B,(CELL*)TR-LCL0, P, CP,
+     LOCAL_CurSlot);
 
   BACKUP_MACHINE_REGS();
   LOCAL_ActiveError->errorNo = YAP_NO_ERROR;
@@ -1766,24 +1765,27 @@ X_API bool YAP_EnterGoal(YAP_PredEntryPtr ape, CELL *ptr, YAP_dogoalinfo *dgi) {
   dgi->p = P;
   dgi->cp = CP;
   dgi->b0 = LCL0 - (CELL *)B;
+  dgi->e = LCL0-ENV;
   dgi->CurSlot = LOCAL_CurSlot;
   // ensure our current ENV receives current P.
 
   Yap_PrepGoal(pe->ArityOfPE, nullptr, B PASS_REGS);
   P = pe->CodeOfPred;
-  // __android_log_print(ANDROID_LOG_INFO, "YAP ", "ap=%p %d %x %x args=%x,%x
-  // slot=%d", pe, pe->CodeOfPred->opc, FAILCODE, Deref(ARG1), Deref(ARG2),
+  // __android_log_print(ANDROID_LOG_INFO, "YAP ", "ap=%p %ld %x %x args=%x,%x
+  // slot=%ld", pe, pe->CodeOfPred->opc, FAILCODE, Deref(ARG1), Deref(ARG2),
   // LOCAL_CurSlot);
   dgi->b = LCL0 - (CELL *)B;
   dgi->h = HR - H0;
   dgi->tr = (CELL *)TR - LCL0;
-  // fprintf(stderr,"PrepGoal: H=%d ENV=%p B=%d TR=%d P=%p CP=%p Slots=%d\n",
+  // fprintf(stderr,"PrepGoal: H=%ld ENV=%p B=%ld TR=%ld P=%p CP=%p Slots=%ld\n",
   //  HR-H0,LCL0-ENV,LCL0-(CELL*)B,(CELL*)TR-LCL0, P, CP, LOCAL_CurSlot);
   out = Yap_exec_absmi(true, false);
-  //   fprintf(stderr,"EnterGoal success=%d: H=%d ENV=%p B=%d TR=%d P=%p CP=%p
-  //   Slots=%d\n", out,HR-H0,LCL0-ENV,LCL0-(CELL*)B,(CELL*)TR-LCL0, P, CP,
+  //   fprintf(stderr,"EnterGoal success=%ld: H=%ld ENV=%p B=%ld TR=%ld P=%p CP=%p
+  //   Slots=%ld\n", out,HR-H0,LCL0-ENV,LCL0-(CELL*)B,(CELL*)TR-LCL0, P, CP,
   //   LOCAL_CurSlot);
-  dgi->b = LCL0 - (CELL *)B;
+  dgi->b = (LCL0 - (CELL*)B);
+  dgi->e = LCL0 - (CELL *)B;
+  dgi->a = LCL0 - (CELL *)ASP;
   if (out) {
     dgi->EndSlot = LOCAL_CurSlot;
     Yap_StartSlots();
@@ -1812,16 +1814,15 @@ X_API bool YAP_RetryGoal(YAP_dogoalinfo *dgi) {
     // get rid of garbage choice-points
     B = myB;
   }
-  // fprintf(stderr,"RetryGoal: H=%d ENV=%p B=%d TR=%d P=%p CP=%p Slots=%d\n",
+  // fprintf(stderr,"RetryGoal: H=%ld ENV=%p B=%ld TR=%ld P=%p CP=%p Slots=%ld\n",
   //  HR-H0,LCL0-ENV,LCL0-(CELL*)B,(CELL*)TR-LCL0, P, CP, LOCAL_CurSlot);
   P = FAILCODE;
   /* make sure we didn't leave live slots when we backtrack */
-  ASP = (CELL *)B;
   LOCAL_CurSlot = dgi->EndSlot;
   out = Yap_exec_absmi(true, true   );
   if (out) {
     dgi->EndSlot = LOCAL_CurSlot;
-    dgi->b = LCL0 - (CELL *)B;
+    dgi->b = myB;
   } else {
     LOCAL_CurSlot =
         dgi->CurSlot; // ignore any slots created within the called goal
@@ -1834,8 +1835,8 @@ X_API bool YAP_LeaveGoal(bool successful, YAP_dogoalinfo *dgi) {
   CACHE_REGS
   choiceptr myB, handler;
 
-  //   fprintf(stderr,"LeaveGoal success=%d: H=%d ENV=%p B=%ld myB=%ld TR=%d
-  //   P=%p CP=%p Slots=%d\n",
+  //   fprintf(stderr,"LeaveGoal success=%ld: H=%d ENV=%p B=%ldd myB=%ldd TR=%ld
+  //   P=%p CP=%p Slots=%ld\n",
   //   successful,HR-H0,LCL0-ENV,LCL0-(CELL*)B,dgi->b0,(CELL*)TR-LCL0, P, CP,
   //   LOCAL_CurSlot);
   BACKUP_MACHINE_REGS();
@@ -1865,10 +1866,12 @@ X_API bool YAP_LeaveGoal(bool successful, YAP_dogoalinfo *dgi) {
   }
   P = dgi->p;
   CP = dgi->cp;
+  ENV = LCL0-dgi->e;
+  ASP = LCL0-dgi->a;
+  B = (choiceptr)(LCL0-dgi->b)
   RECOVER_MACHINE_REGS();
-  //  fprintf(stderr,"LeftGoal success=%d: H=%d ENV=%p B=%d TR=%d P=%p CP=%p
-  //  Slots=%d\n",    successful,HR-H0,LCL0-ENV,LCL0-(CELL*)B,(CELL*)TR-LCL0, P,
-  //  CP, LOCAL_CurSlot);
+   fprintf(stderr,"LeftGoal success=%ld: H=%ld ENV=%ld B=%ld TR=%ld P=%p CP=%p,    Slots=%ld\n",    successful,HR-H0,LCL0-ENV,LCL0-(CELL*)B,(CELL*)TR-LCL0, P,
+    CP, LOCAL_CurSlot);
   return TRUE;
 }
 
@@ -2152,7 +2155,7 @@ int   lvl = push_text_stack();
   sno = Yap_OpenStream(tat, "r", MkAtomTerm(Yap_LookupAtom(fname)),
                        LOCAL_encoding);
     __android_log_print(
-            ANDROID_LOG_INFO, "YAPDroid", "OpenStream got %d ",sno);
+            ANDROID_LOG_INFO, "YAPDroid", "OpenStream got %ld ",sno);
     if (sno < 0 || !Yap_ChDir(dirname((char *)d))) {
     *full = NULL;
     pop_text_stack(lvl);
@@ -2194,7 +2197,7 @@ X_API void YAP_EndConsult(int sno, int *osnop, const char *full) {
   if (osnop >= 0)
     Yap_AddAlias(AtomLoopStream, *osnop);
   Yap_end_consult();
-  __android_log_print(ANDROID_LOG_INFO, "YAPDroid ", " closing %s:%s(%d), %d",
+  __android_log_print(ANDROID_LOG_INFO, "YAPDroid ", " closing %s:%s(%ld), %ld",
                       CurrentModule == 0
                           ? "prolog"
                           : RepAtom(AtomOfTerm(CurrentModule))->StrOfAE,
diff --git a/C/modules.c b/C/modules.c
index 78df7a6d8..bc710a69f 100644
--- a/C/modules.c
+++ b/C/modules.c
@@ -539,7 +539,6 @@ static Int current_source_module(USES_REGS1) {
     Yap_Error(TYPE_ERROR_ATOM, t, NULL);
     return false;
   }
-  Yap_DebugPlWriteln(t);
   LOCAL_SourceModule = CurrentModule = t;
   return true;
 }
diff --git a/CXX/yapi.cpp b/CXX/yapi.cpp
index 6c5b4030e..c0a907381 100644
--- a/CXX/yapi.cpp
+++ b/CXX/yapi.cpp
@@ -613,43 +613,8 @@ bool YAPEngine::mgoal(Term t, Term tmod, bool release) {
 #endif
   CACHE_REGS
   BACKUP_MACHINE_REGS();
-   Term *ts = nullptr;
-  q.CurSlot = Yap_StartSlots();
-  q.p = P;
-  q.cp = CP;
-  Term omod = CurrentModule;
-  PredEntry *ap = nullptr;
-  if (IsStringTerm(tmod))
-    tmod = MkAtomTerm(Yap_LookupAtom(StringOfTerm(tmod)));
-  ap =  Yap_get_pred(t, tmod, "C++");
-  if (ap == nullptr ||
-      ap->OpcodeOfPred == UNDEF_OPCODE) {
-    ap = rewriteUndefEngineQuery(ap, t, tmod);
-  }
-  if (IsApplTerm(t))
-    ts = RepAppl(t) + 1;
-  else if (IsPairTerm(t))
-    ts = RepPair(t);
-  /* legal ap */
-  arity_t arity = ap->ArityOfPE;
-
-  for (arity_t i = 0; i < arity; i++) {
-    XREGS[i + 1] = ts[i];
-  }
-  ts = nullptr;
-  bool result;
-  // allow Prolog style exception handling
-  // don't forget, on success these guys may create slots
-  //__android_log_print(ANDROID_LOG_INFO, "YAPDroid", "exec  ");
-
-   result = (bool)YAP_EnterGoal(ap, nullptr, &q);
-  //  std::cerr << "mgoal "  << YAPTerm(tmod).text() << ":" << YAPTerm(t).text() << "\n";
-
-  YAP_LeaveGoal(result && !release, &q);
-  CurrentModule = LOCAL_SourceModule = omod;
-  //      PyEval_RestoreThread(_save);
-  RECOVER_MACHINE_REGS();
-  return result;
+  bool rc = YAP_RunGoalOnce(t);
+  return rc;
 }
 /**
  * called when a query must be terminated and its state fully recovered,
@@ -670,7 +635,9 @@ Term YAPEngine::fun(Term t) {
   arity_t arity;
   Functor f;
   Atom name;
+  YAP_dogoalinfo backup = q;
 
+  
   if (IsApplTerm(t)) {
     ts = RepAppl(t) + 1;
     f = (Functor)ts[-1];
@@ -719,6 +686,7 @@ Term YAPEngine::fun(Term t) {
     YAP_LeaveGoal(result, &q);
     //      PyEval_RestoreThread(_save);
     RECOVER_MACHINE_REGS();
+    q = backup;
     return ot;
   }
 }
diff --git a/include/YapDefs.h b/include/YapDefs.h
index f1c27bcd0..f2af9cadd 100755
--- a/include/YapDefs.h
+++ b/include/YapDefs.h
@@ -138,7 +138,7 @@ typedef enum {
 
 /* this should be opaque to the user */
 typedef struct {
-  unsigned long b, b0;      //> choice-point at entry
+  unsigned long b, b0, e, a; //> choice-point at entry
   YAP_handle_t CurSlot; //> variables at entry
   YAP_handle_t EndSlot; //> variables at successful execution
   struct yami *p;       //> Program Counter at entry
diff --git a/library/matrix.yap b/library/matrix.yap
index fd5ffcc6e..9efefb539 100644
--- a/library/matrix.yap
+++ b/library/matrix.yap
@@ -653,7 +653,6 @@ Unify  _NElems_ with the type of the elements in  _Matrix_.
 :- use_module(library(maplist)).
 :- use_module(library(mapargs)).
 :- use_module(library(lists)).
-:- start_low_level_trace.
 ( X <== '[]'(Dims0, array) of T ) :-
     var(X),
     (  T== ints -> true ; T== floats),
@@ -661,7 +660,6 @@ Unify  _NElems_ with the type of the elements in  _Matrix_.
     foldl( norm_dim, Dims0, Dims, Bases, 1, _Size ),
     matrix_new( T , Dims, _, X ),
     matrix_base(X, Bases).
-:- stop_low_level_trace.
 ( X <== '[]'(Dims0, array) of T ) :-
     atom(X),
     (  T== ints -> true ; T== floats),
diff --git a/packages/python/py2pl.c b/packages/python/py2pl.c
index b8160d88c..da5a44476 100644
--- a/packages/python/py2pl.c
+++ b/packages/python/py2pl.c
@@ -28,7 +28,7 @@ void YAPPy_ThrowError__(const char *file, const char *function, int lineno,
     // fprintf(stderr, "warning: ");
     Yap_ThrowError__(file, function, lineno, type, wheret, tmpbuf);
   } else {
-    Yap_ThrowError__(file, function, lineno, type, wheret);
+    //    Yap_ThrowError__(file, function, lineno, type, wheret);
   }
 }
 
@@ -329,6 +329,7 @@ bool python_assign(term_t t, PyObject *exp, PyObject *context) {
         int n, i;
         PL_get_name_arity(t, &s, &n);
         PyObject *o = term_to_python(t, true, context, true);
+	PyErr_Print();
         if (PySequence_Check(o) && PySequence_Length(o) == n) {
           for (i = 1; i <= n; i++) {
             PyObject *p;
@@ -337,12 +338,15 @@ bool python_assign(term_t t, PyObject *exp, PyObject *context) {
               o = false;
               p = Py_None;
             }
+	    
             if ((p = PySequence_GetItem(exp, i - 1)) == NULL)
               p = Py_None;
             else if (!python_assign(arg, p, NULL)) {
               PL_reset_term_refs(tail);
               o = NULL;
-            }
+            } else {
+ 	      PyErr_Print();
+	    }
           }
           return true;
         }
@@ -350,6 +354,7 @@ bool python_assign(term_t t, PyObject *exp, PyObject *context) {
     }
     PL_reset_term_refs(tail);
   }
+ 	      PyErr_Print();
     return NULL;
   }
 }