From a6e578090cc4734950e1298cc4f5f237f8d165bb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=ADtor=20Santos=20Costa?= <vsc@dcc.fc.up.pt>
Date: Tue, 18 Sep 2018 19:27:10 +0100
Subject: [PATCH] C-interface

---
 C/c_interface.c           | 23 +++++++++++++++--------
 CXX/yapi.cpp              | 12 +++++++++---
 CXX/yapq.hh               |  1 -
 packages/python/pl2py.c   |  6 +++---
 packages/python/py2pl.c   |  3 ++-
 packages/python/pypreds.c | 13 +++++++------
 6 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/C/c_interface.c b/C/c_interface.c
index 1a30a292a..3ca80bf18 100755
--- a/C/c_interface.c
+++ b/C/c_interface.c
@@ -1813,21 +1813,23 @@ X_API bool YAP_LeaveGoal(bool successful, YAP_dogoalinfo *dgi) {
 	   //&& LOCAL_CBorder > LCL0 - (CELL *)handler
 	   //&& handler->cp_ap != NOCODE
 	 && handler->cp_b != NULL
-	   && handler != myB
+	   && handler <= myB
 	 ) {
     handler->cp_ap = TRUSTFAILCODE;
-    handler = handler->cp_b;
-  }
-  if (LOCAL_PrologMode & AsyncIntMode) {
-    Yap_signal(YAP_FAIL_SIGNAL);
-  }
   B = handler;
+    handler = handler->cp_b;
   if (successful) {
     Yap_TrimTrail();
-    CP = dgi->cp;
-    P = dgi->p;
   } else {
+    P=FAILCODE;
     Yap_exec_absmi(true, YAP_EXEC_ABSMI);
+  }
+  }
+    if (successful) {
+      CP = dgi->cp;
+      P = dgi->p;
+    
+  } else {
     LOCAL_CurSlot = dgi->CurSlot;
     ENV = YENV = B->cp_env;
     HR = B->cp_h;
@@ -1835,6 +1837,11 @@ X_API bool YAP_LeaveGoal(bool successful, YAP_dogoalinfo *dgi) {
     // use the current choicepoint
     //  B=B->cp_b;
     ASP=(CELL*)B;
+  }
+    if (B)
+      B = B->cp_b;
+  if (LOCAL_PrologMode & AsyncIntMode) {
+    Yap_signal(YAP_FAIL_SIGNAL);
   }
   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);
diff --git a/CXX/yapi.cpp b/CXX/yapi.cpp
index cc2587370..9518183e7 100644
--- a/CXX/yapi.cpp
+++ b/CXX/yapi.cpp
@@ -667,8 +667,10 @@ Term YAPEngine::fun(Term t) {
     throw YAPError(SOURCE(), TYPE_ERROR_CALLABLE, t, 0);
     return 0L;
   }
-  XREGS[arity + 1] = MkVarTerm();
+  Term ot = XREGS[arity + 1] = MkVarTerm();
+  yhandle_t h = Yap_InitHandle(ot); 
   arity++;
+  HR += arity;
   f = Yap_MkFunctor(name, arity);
   ap = (PredEntry *)(PredPropByFunc(f, tmod));
   if (ap == nullptr || ap->OpcodeOfPred == UNDEF_OPCODE) {
@@ -683,12 +685,16 @@ Term YAPEngine::fun(Term t) {
   //__android_log_print(ANDROID_LOG_INFO, "YAPDroid", "exec  ");
 
   bool result = (bool)YAP_EnterGoal(ap, nullptr, &q);
-  YAPCatchError();
+    if (result)
+      ot = Yap_GetFromHandle(h);
+    else
+      ot = TermNone;
+    YAPCatchError();
   {
     YAP_LeaveGoal(result, &q);
     //      PyEval_RestoreThread(_save);
     RECOVER_MACHINE_REGS();
-    return result;
+    return ot;
   }
 }
 
diff --git a/CXX/yapq.hh b/CXX/yapq.hh
index 6fcaba6bc..dcfadc7f3 100644
--- a/CXX/yapq.hh
+++ b/CXX/yapq.hh
@@ -367,7 +367,6 @@ public:
   //> output.
   YAPTerm funCall(YAPTerm t) { return YAPTerm(fun(t.term())); };
   Term fun(Term t);
-  Term fun(YAPTerm t) { return fun(t.term()); };
   //> set a StringFlag, usually a path
   //>
   bool setStringFlag(std::string arg, std::string path) {
diff --git a/packages/python/pl2py.c b/packages/python/pl2py.c
index 9a77f8341..5cb964318 100644
--- a/packages/python/pl2py.c
+++ b/packages/python/pl2py.c
@@ -387,7 +387,7 @@ PyObject *term_to_python(term_t t, bool eval, PyObject *o, bool cvt) {
 	  if (entry_to_dictionary(dict, yt, eval, cvt))
 	    return dict;
 	  else
-	    return NULL;         
+	    return Py_None;         
         }
        atom_t name;
         int arity;
@@ -424,8 +424,8 @@ PyObject *term_to_python(term_t t, bool eval, PyObject *o, bool cvt) {
 }
 
 PyObject *yap_to_python(YAP_Term t, bool eval, PyObject *o, bool cvt) {
-  if (t == 0)
-    return NULL;
+  if (t == 0 || t == TermNone)
+    return Py_None;
   term_t yt = YAP_InitSlot(t);
   o = term_to_python(yt, eval, o, cvt);
   PL_reset_term_refs(yt);
diff --git a/packages/python/py2pl.c b/packages/python/py2pl.c
index 7193c28a0..9b88d91cc 100644
--- a/packages/python/py2pl.c
+++ b/packages/python/py2pl.c
@@ -55,8 +55,9 @@ static Term python_to_term__(PyObject *pVal) {
   if (pVal == Py_None) {
     // fputs("<<*** ",stderr);Yap_DebugPlWrite(YAP_GetFromSlot(t));   fputs("
     // >>***\n",stderr);
-    return YAP_MkVarTerm();
+    //return YAP_MkVarTerm();
     // fputs("<<*** ",stderr);Yap_DebugPlWrite(YAP_GetFromSlot(t));   fputs("
+    return MkAtomTerm(Yap_LookupAtom("none"));
     // >>***\n",stderr);
   } else if (PyBool_Check(pVal)) {
     if(PyObject_IsTrue(pVal)) return TermTrue;
diff --git a/packages/python/pypreds.c b/packages/python/pypreds.c
index 3f3179588..f7f642a3c 100644
--- a/packages/python/pypreds.c
+++ b/packages/python/pypreds.c
@@ -238,15 +238,16 @@ static foreign_t python_string_to(term_t f) {
     if (!PL_get_chars(f, &s, CVT_ALL | CVT_EXCEPTION | REP_UTF8)) {
       pyErrorAndReturn(false);
     }
-    if (!strcmp(s,"atom"))
+    if (!strcmp(s,"atom")) {
       pyStringToString = false;
-    if (!strcmp(s,"string"))
+      return true;
+    }
+    if (!strcmp(s,"string")) {
       pyStringToString = true;
-    else
-      return false;
-    return true;
+      return true;
+    }
   }
-  return true;
+  return false;
 }
 
 static foreign_t python_builtin_eval(term_t caller, term_t dict, term_t out) {