fixes

packages/python/py2pl.c

@@ -90,7 +90,10 @@ else if (PyUnicode_Check(pVal)) {
       rc = rc && PL_unify_atom_chars(t, s);
     else
 #endif
+      if  (pyStringToString)
   return MkStringTerm(s);
+      else
+	return MkAtomTerm(Yap_LookupAtom(s));
 }
 else if (PyByteArray_Check(pVal)) {
   return MkStringTerm(PyByteArray_AsString(pVal));

packages/python/py4yap.h

@@ -93,6 +93,7 @@ extern PyObject *py_Sys;
 #define py_Builtin PyEval_GetBuiltins()
 
 extern X_API bool python_in_python;
+extern bool pyStringToString;
 
 extern bool python_release_GIL(term_t gstate);
 extern term_t python_acquire_GIL(void);

packages/python/pypreds.c

@@ -231,6 +231,24 @@ static foreign_t assign_python(term_t exp, term_t name) {
   pyErrorAndReturn(b);
 }
 
+
+static foreign_t python_string_to(term_t f) {
+  if (PL_is_atom(f)) {
+    char *s = NULL;
+    if (!PL_get_chars(f, &s, CVT_ALL | CVT_EXCEPTION | REP_UTF8)) {
+      pyErrorAndReturn(false);
+    }
+    if (!strcmp(s,"atom"))
+      pyStringToString = false;
+    if (!strcmp(s,"string"))
+      pyStringToString = true;
+    else
+      return false;
+    return true;
+  }
+  return true;
+}
+
 static foreign_t python_builtin_eval(term_t caller, term_t dict, term_t out) {
   PyErr_Clear();
   PyObject *pI, *pArgs, *pOut;
@@ -759,6 +777,7 @@ install_t install_pypreds(void) {
   PL_register_foreign("python_access", 3, python_access, 0);
   PL_register_foreign("python_threaded", 0, p_python_threaded, 0);
   PL_register_foreign("python_clear_errors", 0, python_clear_errors, 0);
+  PL_register_foreign("python_string_to", 0, python_string_to, 1);
 
   init_python_vfs();
 }

packages/python/python.c

@@ -28,6 +28,8 @@ PyObject *py_Context;
 
 X_API PyObject *Py_f2p;
 
+bool pyStringToString;
+
 extern X_API bool python_in_python;
 
 static void add_modules(void) {

packages/python/python.pl

@@ -28,6 +28,7 @@
 	   array_to_python_tuple/4,
 	   array_to_python_view/5,
 	   python/2,
+	   python_string_to/1,
 	   acquire_GIL/0,
 	   release_GIL/0,
 	   python_threaded/0,