#ifdef _XOPEN_SOURCE
#undef _XOPEN_SOURCE // python does its own thing
#endif
#include <Python.h>
#include <SWI-Prolog.h>
#ifdef HAVE_STAT
#undef HAVE_STATa
#endif
#include <assert.h>

//@{

/** @brief  Prolog to Python library
*
*
* Please look at python.pl for more information, and to real.pl and real.c
* for related work.
*/

static atom_t ATOM_true, ATOM_false, ATOM_colon, ATOM_dot, ATOM_none, ATOM_t,
    ATOM_comma, ATOM_builtin;

static functor_t FUNCTOR_dollar1, FUNCTOR_abs1, FUNCTOR_all1, FUNCTOR_any1,
    FUNCTOR_bin1, FUNCTOR_brackets1, FUNCTOR_comma2, FUNCTOR_dir1,
    FUNCTOR_float1, FUNCTOR_int1, FUNCTOR_iter1, FUNCTOR_iter2, FUNCTOR_long1,
    FUNCTOR_len1, FUNCTOR_curly1, FUNCTOR_ord1, FUNCTOR_range1, FUNCTOR_range2,
    FUNCTOR_range3, FUNCTOR_sum1, FUNCTOR_pointer1, FUNCTOR_complex2,
    FUNCTOR_plus2, FUNCTOR_sub2, FUNCTOR_mul2, FUNCTOR_div2, FUNCTOR_hat2,
    FUNCTOR_colon2, FUNCTOR_comma2, FUNCTOR_equal2, FUNCTOR_sqbrackets2,
    FUNCTOR_dot2;

static PyObject *py_Main;
static PyObject *py_Builtin;
static PyObject *term_to_python(term_t t);
static foreign_t python_to_ptr(PyObject *pVal, term_t t);
static PyObject *atom_to_python_string(term_t t);
static int assign_python(PyObject *root, term_t t, PyObject *e);

static PyObject *ActiveModules[32];
static int active_modules = 0;

static inline int proper_ascii_string(char *s) {
  unsigned char c;

  while ((c = *s++)) {
    if (c > 127)
      return FALSE;
  }
  return TRUE;
}

static Py_ssize_t get_p_int(PyObject *o, Py_ssize_t def) {
  if (o == NULL)
    return def;
  if (PyLong_Check(o)) {
    return PyLong_AsLong(o);
#if PY_MAJOR_VERSION < 3
  } else if (PyInt_Check(o)) {
    return PyInt_AsLong(o);
#endif
  }
  return def;
}

static PyObject *find_obj(PyObject *ob, term_t lhs) {
  char *s;
  PyObject *out, *pName;
  int arity = 0;

  if (!PL_get_atom_chars(lhs, &s)) {
    atom_t name;
    if (!PL_get_name_arity(lhs, &name, &arity))
      return NULL;
    s = PL_atom_chars(name);
  }
  if (ob) {
    out = PyObject_GetAttrString(ob, s);
    return out;
  }
  if (!ob && !arity) {
#if PY_MAJOR_VERSION < 3
    pName = PyString_FromString(s);
#else
    pName = PyUnicode_FromString(s);
#endif
    if (pName == NULL) {
      return NULL;
    }
    if ((out = PyImport_Import(pName))) {
      Py_IncRef(out);
      //      Py_DecRef(pName); ??
      return out;
    }
  }
  if (!ob && py_Main && (out = PyObject_GetAttrString(py_Main, s)))
    return out;
  return NULL;
}

static int copy_to_dictionary(PyObject *dict, term_t targ, term_t taux) {
  PyObject *lhs, *rhs;
  term_t tleft = PL_new_term_ref(), tright = PL_new_term_ref();

  while (true) {
    functor_t fun;

    if (!PL_get_functor(targ, &fun))
      return false;
    if (fun == FUNCTOR_comma2) {
      if (!PL_get_arg(1, targ, taux)) {
        return false;
      }
      if (!PL_get_arg(1, taux, tleft)) {
        return FALSE;
      }
      lhs = term_to_python(tleft);
      if (!PL_get_arg(2, taux, tright)) {
        return FALSE;
      }
      rhs = term_to_python(tright);
      if (PyDict_SetItem(dict, lhs, rhs) < 0) {
        return FALSE;
      }
      // PyObject_Print(dict, stderr, 0); fprintf(stderr,"\n");
      // Py_DECREF(lhs);
      // Py_DECREF(rhs);

      if (!PL_get_arg(1, targ, targ)) {
        return FALSE;
      }
    } else {
      if (!PL_get_arg(1, targ, tleft)) {
        return FALSE;
      }
      lhs = atom_to_python_string(tleft);
      if (lhs == NULL) {
        return FALSE;
      }
      if (!PL_get_arg(2, targ, tright)) {
        return FALSE;
      }
      rhs = term_to_python(tright);
      if (rhs == NULL) {
        PyErr_Print();
        return FALSE;
      }
      if (PyDict_SetItem(dict, lhs, rhs) < 0) {
        return FALSE;
      }
      // PyObject_Print(dict, stderr, 0); fprintf(stderr,"\n");
      // Py_DECREF(lhs);
      // Py_DECREF(rhs);
      break;
    }
  }
  return TRUE;
}

/**
*
* @section Python Built-Ins
*
* The Python engine includes a large number of Python built-ins. Some
* of them are interfaced here.
*/

//@{

/**
* Python abs
*
* @param t Prolog term with a number
*
* @return a Python object with the number's absolute value
*/

static PyObject *bip_abs(term_t t) {
  PyObject *pVal, *nVal;

  if (!PL_get_arg(1, t, t))
    return NULL;
  pVal = term_to_python(t);
  nVal = PyNumber_Absolute(pVal);
  Py_DecRef(pVal);
  return nVal;
}

/**
* Python all
*
* @param t Prolog term with a previously constructed Python iterator
*
* @return the Python boolean `True` if all elements of the iterator are `True`,
*    `False`  otherwise.
*/
static PyObject *bip_all(term_t t) {
  PyObject *it, *item, *v;
  PyObject *(*iternext)(PyObject *);
  int cmp;

  if (!PL_get_arg(1, t, t))
    return NULL;
  v = term_to_python(t);
  it = PyObject_GetIter(v);
  if (it == NULL)
    return NULL;
  iternext = *Py_TYPE(it)->tp_iternext;

  //  PyObject_Print(v, stderr, 0);
  for (;;) {
    item = iternext(it);
    if (item == NULL)
      break;
    cmp = PyObject_IsTrue(item);
    Py_DECREF(item);
    if (cmp < 0) {
      Py_DECREF(it);
      return NULL;
    }
    if (cmp == 0) {
      Py_DECREF(it);
      return Py_False;
    }
  }
  Py_DECREF(it);
  if (PyErr_Occurred()) {
    if (PyErr_ExceptionMatches(PyExc_StopIteration))
      PyErr_Clear();
    else
      return NULL;
  }
  return Py_True;
}

/**
* Python any
*
* @param t Prolog term with a previously constructed Python iterator
*
* @return the Python boolean `True` if any element of the iterator is `True`,
*    `False`  if all of them are false.
*/
static PyObject *bip_any(term_t t) {
  PyObject *it, *item, *v;
  PyObject *(*iternext)(PyObject *);
  int cmp;

  if (!PL_get_arg(1, t, t))
    return NULL;
  v = term_to_python(t);
  it = PyObject_GetIter(v);
  if (it == NULL)
    return NULL;
  iternext = *Py_TYPE(it)->tp_iternext;

  for (;;) {
    item = iternext(it);
    if (item == NULL)
      break;
    cmp = PyObject_IsTrue(item);
    Py_DECREF(item);
    if (cmp < 0) {
      Py_DECREF(it);
      return NULL;
    }
    if (cmp == 1) {
      Py_DECREF(it);
      Py_RETURN_TRUE;
    }
  }
  Py_DECREF(it);
  if (PyErr_Occurred()) {
    if (PyErr_ExceptionMatches(PyExc_StopIteration))
      PyErr_Clear();
    else
      return NULL;
  }
  Py_RETURN_FALSE;
}

static PyObject *bip_bin(term_t t) {
  PyObject *v;

  if (!PL_get_arg(1, t, t))
    return NULL;
  v = term_to_python(t);
  return PyNumber_ToBase(v, 2);
}

static PyObject *bip_float(term_t t) {
  PyObject *pVal, *o;

  if (!PL_get_arg(1, t, t))
    return NULL;
  pVal = term_to_python(t);
  if (PyLong_Check(pVal)) {
    o = PyFloat_FromDouble(PyLong_AsLong(pVal));
#if PY_MAJOR_VERSION < 3
  } else if (PyInt_Check(pVal)) {
    o = PyFloat_FromDouble(PyInt_AsLong(pVal));
#endif
  } else if (PyFloat_Check(pVal)) {
    return pVal;
  } else
    return NULL;
  Py_DECREF(pVal);
  return o;
}

static PyObject *bip_int(term_t t) {
  PyObject *pVal, *o;

  if (!PL_get_arg(1, t, t))
    return NULL;
  pVal = term_to_python(t);
#if PY_MAJOR_VERSION < 3
  if (PyLong_Check(pVal)) {
    o = PyInt_FromLong(PyLong_AsLong(pVal));
  } else if (PyInt_Check(pVal)) {
    return pVal;
#else
  if (PyLong_Check(pVal)) {
    return pVal;
#endif
  } else if (PyFloat_Check(pVal)) {
#if PY_MAJOR_VERSION < 3
    o = PyInt_FromLong(PyFloat_AsDouble(pVal));
#else
    o = PyLong_FromDouble(PyFloat_AsDouble(pVal));
#endif
  } else
    return NULL;
  Py_DECREF(pVal);
  return o;
}

static PyObject *bip_long(term_t t) {
  PyObject *pVal, *o;

  if (!PL_get_arg(1, t, t))
    return NULL;
  pVal = term_to_python(t);
  if (PyLong_Check(pVal)) {
    return pVal;
#if PY_MAJOR_VERSION < 3
  } else if (PyInt_Check(pVal)) {
    o = PyLong_FromLong(PyInt_AsLong(pVal));
#endif
  } else if (PyFloat_Check(pVal)) {
    o = PyLong_FromLong(PyFloat_AsDouble(pVal));
  } else
    return NULL;
  Py_DECREF(pVal);
  return o;
}

static PyObject *bip_iter(term_t t) {
  PyObject *v;

  if (!PL_get_arg(1, t, t))
    return NULL;
  v = term_to_python(t);
  return PyObject_GetIter(v);
}

static PyObject *bip_ord(term_t t) {
  PyObject *pVal;
  Py_ssize_t size;

  if (!PL_get_arg(1, t, t))
    return NULL;
  pVal = term_to_python(t);
  if (PyUnicode_Check(pVal)) {
#if PY_MAJOR_VERSION < 3
    size = PyUnicode_GET_SIZE(pVal);
#else
    size = PyUnicode_GetLength(pVal);
#endif
    if (size == 1) {
#if PY_MAJOR_VERSION < 3
      long ord = (long)*PyUnicode_AS_UNICODE(pVal);
      return PyInt_FromLong(ord);
#else
      Py_UCS4 ord = PyUnicode_ReadChar(pVal, 0);
      return PyLong_FromLong(ord);
#endif
    }
    return NULL;
  } else if (PyByteArray_Check(pVal)) {
    char *s = PyByteArray_AsString(pVal);

    if (s[1])
      return NULL;
#if PY_MAJOR_VERSION < 3
    return PyInt_FromLong(s[0]);
  } else if (PyString_Check(pVal)) {
    char *s = PyString_AsString(pVal);

    if (s[1])
      return NULL;
    return PyInt_FromLong(s[0]);
#else
    return PyLong_FromLong(s[0]);
#endif
  } else
    return NULL;
}

static PyObject *bip_sum(term_t t) {
  PyObject *seq;
  PyObject *result = NULL;
  PyObject *temp, *item, *iter;

  if (!PL_get_arg(1, t, t))
    return NULL;
  seq = term_to_python(t);
  iter = PyObject_GetIter(seq);
  if (iter == NULL)
    return NULL;

  if (result == NULL) {
#if PY_MAJOR_VERSION < 3
    result = PyInt_FromLong(0);
#else
    result = PyLong_FromLong(0);
#endif
    if (result == NULL) {
      Py_DECREF(iter);
      return NULL;
    }
  } else {
#if PY_MAJOR_VERSION < 3
    /* reject string values for 'start' parameter */
    if (PyObject_TypeCheck(result, &PyBaseString_Type)) {
      PyErr_SetString(PyExc_TypeError,
                      "sum() can't sum strings [use ''.join(seq) instead]");
      Py_DECREF(iter);
      return NULL;
    }
    Py_INCREF(result);
#endif
  }

#ifndef SLOW_SUM
/* Fast addition by keeping temporary sums in C instead of new Python objects.
Assumes all inputs are the same type.  If the assumption fails, default
to the more general routine.
*/
#if PY_MAJOR_VERSION < 3
  if (PyInt_CheckExact(result)) {
    long i_result = PyInt_AS_LONG(result);
#else
  if (PyLong_CheckExact(result)) {
    long i_result = PyLong_AS_LONG(result);
#endif
    Py_DECREF(result);
    result = NULL;
    while (result == NULL) {
      item = PyIter_Next(iter);
      if (item == NULL) {
        Py_DECREF(iter);
        if (PyErr_Occurred())
          return NULL;
#if PY_MAJOR_VERSION < 3
        return PyInt_FromLong(i_result);
#else
        return PyLong_FromLong(i_result);
#endif
      }
#if PY_MAJOR_VERSION < 3
      if (PyInt_CheckExact(item)) {
        long b = PyInt_AS_LONG(item);
#else
      if (PyLong_CheckExact(item)) {
        long b = PyLong_AS_LONG(item);
#endif
        long x = i_result + b;
        if ((x ^ i_result) >= 0 || (x ^ b) >= 0) {
          i_result = x;
          Py_DECREF(item);
          continue;
        }
      }
/* Either overflowed or is not an int. Restore real objects and process normally
 */
#if PY_MAJOR_VERSION < 3
      result = PyInt_FromLong(i_result);
#else
      result = PyLong_FromLong(i_result);
#endif
      temp = PyNumber_Add(result, item);
      Py_DECREF(result);
      Py_DECREF(item);
      result = temp;
      if (result == NULL) {
        Py_DECREF(iter);
        return NULL;
      }
    }
  }

  if (PyFloat_CheckExact(result)) {
    double f_result = PyFloat_AS_DOUBLE(result);
    Py_DECREF(result);
    result = NULL;
    while (result == NULL) {
      item = PyIter_Next(iter);
      if (item == NULL) {
        Py_DECREF(iter);
        if (PyErr_Occurred())
          return NULL;
        return PyFloat_FromDouble(f_result);
      }
      if (PyFloat_CheckExact(item)) {
        PyFPE_START_PROTECT("add", Py_DECREF(item); Py_DECREF(iter); return 0)
            f_result += PyFloat_AS_DOUBLE(item);
        PyFPE_END_PROTECT(f_result) Py_DECREF(item);
        continue;
      }
#if PY_MAJOR_VERSION < 3
      if (PyInt_CheckExact(item)) {
        PyFPE_START_PROTECT("add", Py_DECREF(item); Py_DECREF(iter); return 0)
            f_result += (double)PyInt_AS_LONG(item);
        PyFPE_END_PROTECT(f_result) Py_DECREF(item);
        continue;
      }
#else
      if (PyLong_CheckExact(item)) {
        PyFPE_START_PROTECT("add", Py_DECREF(item); Py_DECREF(iter); return 0)
            f_result += PyLong_AsDouble(item);
        PyFPE_END_PROTECT(f_result) Py_DECREF(item);
        continue;
      }
#endif
      result = PyFloat_FromDouble(f_result);
      temp = PyNumber_Add(result, item);
      Py_DECREF(result);
      Py_DECREF(item);
      result = temp;
      if (result == NULL) {
        Py_DECREF(iter);
        return NULL;
      }
    }
#endif
  }

  for (;;) {
    item = PyIter_Next(iter);
    if (item == NULL) {
      /* error, or end-of-sequence */
      if (PyErr_Occurred()) {
        Py_DECREF(result);
        result = NULL;
      }
      break;
    }
    /* It's tempting to use PyNumber_InPlaceAdd instead of
    PyNumber_Add here, to avoid quadratic running time
    when doing 'sum(list_of_lists, [])'.  However, this
    would produce a change in behaviour: a snippet like

    empty = []
    sum([[x] for x in range(10)], empty)

    would change the value of empty. */
    temp = PyNumber_Add(result, item);
    Py_DECREF(result);
    Py_DECREF(item);
    result = temp;
    if (result == NULL)
      break;
  }
  Py_DECREF(iter);
  return result;
}

//@}

static long get_int(term_t arg) {
  long ilow;

  if (!PL_get_long(arg, &ilow)) {
    PyObject *low = term_to_python(arg);
    if (PyLong_Check(low)) {
      return PyLong_AsLong(low);
#if PY_MAJOR_VERSION < 3
    } else if (PyInt_Check(low)) {
      return PyInt_AsLong(low);
#endif
    } else {
      return 0;
    }
  }
  return ilow;
}

/* Return number of items in range/xrange (lo, hi, step).  step > 0
* required.  Return a value < 0 if & only if the true value is too
* large to fit in a signed long.
*/
static long get_len_of_range(long lo, long hi, long step) {
  /* -------------------------------------------------------------
  If lo >= hi, the range is empty.
  Else if n values are in the range, the last one is
  lo + (n-1)*step, which must be <= hi-1.  Rearranging,
  n <= (hi - lo - 1)/step + 1, so taking the floor of the RHS gives
  the proper value.  Since lo < hi in this case, hi-lo-1 >= 0, so
  the RHS is non-negative and so truncation is the same as the
  floor.  Letting M be the largest positive long, the worst case
  for the RHS numerator is hi=M, lo=-M-1, and then
  hi-lo-1 = M-(-M-1)-1 = 2*M.  Therefore unsigned long has enough
  precision to compute the RHS exactly.
  ---------------------------------------------------------------*/
  long n = 0;
  if (lo < hi) {
    unsigned long uhi = (unsigned long)hi;
    unsigned long ulo = (unsigned long)lo;
    unsigned long diff = uhi - ulo - 1;
    n = (long)(diff / (unsigned long)step + 1);
  }
  return n;
}

static PyObject *bip_range(term_t t) {
  long ilow = 0, ihigh = 0, istep = 1;
  long bign;
  Py_ssize_t i, n;
  int arity;
  atom_t name;
  term_t arg = PL_new_term_ref();

  PyObject *v;

  if (!PL_get_name_arity(t, &name, &arity))
    return NULL;
  if (!PL_get_arg(1, t, arg))
    return NULL;
  ilow = get_int(arg);
  if (arity == 1) {
    ihigh = ilow;
    ilow = 0;
  } else {
    if (!PL_get_arg(2, t, arg))
      return NULL;
    ihigh = get_int(arg);
    if (arity == 3) {
      if (!PL_get_arg(3, t, arg))
        return NULL;
      istep = get_int(arg);
    }
  }
  if (istep == 0) {
    PyErr_SetString(PyExc_ValueError, "range() step argument must not be zero");
    return NULL;
  }
  if (istep > 0)
    bign = get_len_of_range(ilow, ihigh, istep);
  else
    bign = get_len_of_range(ihigh, ilow, -istep);
  n = (Py_ssize_t)bign;
  if (bign < 0 || (long)n != bign) {
    PyErr_SetString(PyExc_OverflowError, "range() result has too many items");
    return NULL;
  }
  v = PyList_New(n);
  if (v == NULL)
    return NULL;
  for (i = 0; i < n; i++) {
#if PY_MAJOR_VERSION < 3
    PyObject *w = PyInt_FromLong(ilow);
#else
    PyObject *w = PyLong_FromLong(ilow);
#endif
    if (w == NULL) {
      Py_DECREF(v);
      return NULL;
    }
    PyList_SET_ITEM(v, i, w);
    ilow += istep;
  }
  return v;
}

static PyObject *atom_to_python_string(term_t t) {
  // Yap_DebugPlWrite(YAP_GetFromSlot(t));        fprintf(stderr, " here I
  // am\n");
  char *s;
  if (!PL_get_atom_chars(t, &s))
    return NULL;
/* return __main__,s */
#if PY_MAJOR_VERSION < 3
  if (proper_ascii_string(s)) {
    return PyString_FromStringAndSize(s, strlen(s));
  } else
#endif
  {
    PyObject *pobj = PyUnicode_DecodeUTF8(s, strlen(s), NULL);
    // fprintf(stderr, "%s\n", s);
    return pobj;
  }
}

/**
* term_to_python translates and evaluates from Prolog to Python
*
* @param t handle to Prolog term
*
* @return a Python object descriptor or NULL if failed
*/

static PyObject *term_to_python(term_t t) {
  // Yap_DebugPlWrite(YAP_GetFromSlot(t));        fprintf(stderr, " here I
  // am\n");
  switch (PL_term_type(t)) {
  case PL_VARIABLE:
    return NULL;
  case PL_ATOM: {
    atom_t at;

    if (PL_get_atom(t, &at)) {
      if (at == ATOM_true)
        return Py_True;
      if (at == ATOM_false)
        return Py_False;
      if (at == ATOM_none)
        return Py_None;
      else {
        char *s;
        if (!PL_get_atom_chars(t, &s))
          return NULL;
        /* return __main__,s */
        PyObject *o = PyObject_GetAttrString(py_Main, s);
        if (o) {
          Py_IncRef(o);
          return o;
        } else {
          PyErr_Print();
          return NULL;
        }
      }
    }
  } break;
  case PL_STRING: {
    char *s;
    if (!PL_get_chars(t, &s,
                      REP_UTF8 | CVT_ATOM | CVT_STRING | BUF_DISCARDABLE)) {
      return NULL;
    }
#if PY_MAJOR_VERSION < 3
    if (proper_ascii_string(s)) {
      return PyString_FromStringAndSize(s, strlen(s));
    } else
#endif
    {
      PyObject *pobj = PyUnicode_DecodeUTF8(s, strlen(s), NULL);
      // fprintf(stderr, "%s\n", s);
      return pobj;
    }
  } break;
  case PL_INTEGER: {
    int64_t j;
    if (!PL_get_int64_ex(t, &j))
      return NULL;
#if PY_MAJOR_VERSION < 3
    return PyInt_FromLong(j);
#else
    return PyLong_FromLong(j);
#endif
  }
  case PL_FLOAT: {
    double fl;
    if (!PL_get_float(t, &fl))
      return NULL;
    return PyFloat_FromDouble(fl);
  }
  case PL_TERM:
    if (PL_is_list(t)) {
      size_t len, i;
      term_t tail = PL_new_term_ref(), arg;
      PyObject *out;

      PL_skip_list(t, tail, &len);
      if (!PL_get_nil(tail))
        return NULL;
      arg = tail;
      out = PyList_New(len);
      if (!out)
        return NULL;

      for (i = 0; i < len; i++) {
        if (!PL_get_list(t, arg, t)) {
          return NULL;
        }
        if (PyList_SetItem(out, i, term_to_python(arg)) < 0)
          return NULL;
      }
      return out;
    } else {
      functor_t fun;

      if (!PL_get_functor(t, &fun))
        return NULL;
      if (fun == FUNCTOR_dollar1) {
        char *s;
        term_t targ = PL_new_term_ref();
        if (!PL_get_arg(1, t, targ))
          return NULL;
        if (!PL_get_atom_chars(targ, &s))
          return NULL;
        /* return __main__,s */
        return PyObject_GetAttrString(py_Main, s);
      } else if (fun == FUNCTOR_pointer1) {
        void *ptr;
        term_t targ = PL_new_term_ref();

        if (!PL_get_arg(1, t, targ))
          return NULL;
        if (!PL_get_pointer(targ, &ptr))
          return NULL;
        /* return __main__,s */
        return (PyObject *)ptr;
      } else if (fun == FUNCTOR_brackets1) {
        if (!PL_get_arg(1, t, t))
          return NULL;
        return term_to_python(t);
      } else if (fun == FUNCTOR_abs1) {
        return bip_abs(t);
      } else if (fun == FUNCTOR_all1) {
        return bip_all(t);
      } else if (fun == FUNCTOR_any1) {
        return bip_any(t);
      } else if (fun == FUNCTOR_bin1) {
        return bip_bin(t);
      } else if (fun == FUNCTOR_ord1) {
        return bip_ord(t);
      } else if (fun == FUNCTOR_int1) {
        return bip_int(t);
      } else if (fun == FUNCTOR_long1) {
        return bip_long(t);
      } else if (fun == FUNCTOR_float1) {
        return bip_float(t);
      } else if (fun == FUNCTOR_iter1) {
        return bip_iter(t);
      } else if (fun == FUNCTOR_range1 || fun == FUNCTOR_range2 ||
                 fun == FUNCTOR_range3) {
        return bip_range(t);
      } else if (fun == FUNCTOR_sum1) {
        return bip_sum(t);
      } else if (fun == FUNCTOR_len1) {
        term_t targ = PL_new_term_ref();
        PyObject *ptr;

        if (!PL_get_arg(1, t, targ))
          return NULL;
        ptr = term_to_python(targ);
        return PyLong_FromLong(PyObject_Length(ptr));
      } else if (fun == FUNCTOR_dir1) {
        term_t targ = PL_new_term_ref();
        PyObject *ptr;

        if (!PL_get_arg(1, t, targ))
          return NULL;
        ptr = term_to_python(targ);
        return PyObject_Dir(ptr);
      } else if (fun == FUNCTOR_complex2) {
        term_t targ = PL_new_term_ref();
        PyObject *lhs, *rhs;
        double d1, d2;

        if (!PL_get_arg(1, t, targ))
          return NULL;
        lhs = term_to_python(targ);
        if (!PyNumber_Check(lhs))
          return NULL;
        if (PyFloat_Check(lhs)) {
          d1 = PyFloat_AsDouble(lhs);
        } else if (PyLong_Check(lhs)) {
          d1 = PyLong_AsLong(lhs);
#if PY_MAJOR_VERSION < 3
        } else if (PyInt_Check(lhs)) {
          d1 = PyInt_AsLong(lhs);
#endif
        } else {
          return NULL;
        }
        if (!PL_get_arg(2, t, targ))
          return NULL;
        rhs = term_to_python(targ);
        if (!PyNumber_Check(rhs))
          return NULL;
        if (PyFloat_Check(rhs)) {
          d2 = PyFloat_AsDouble(rhs);
        } else if (PyLong_Check(rhs)) {
          d2 = PyLong_AsLong(rhs);
#if PY_MAJOR_VERSION < 3
        } else if (PyInt_Check(rhs)) {
          d2 = PyInt_AsLong(rhs);
#endif
        } else {
          return NULL;
        }

        return PyComplex_FromDoubles(d1, d2);
      } else if (fun == FUNCTOR_curly1) {
        term_t targ = PL_new_term_ref(), taux = PL_new_term_ref();
        PyObject *dict;

        if (!PL_get_arg(1, t, t))
          return NULL;
        if (!(dict = PyDict_New()))
          return NULL;
        while (PL_is_functor(t, FUNCTOR_comma2)) {
          if (!PL_get_arg(1, t, targ))
            return NULL;
          if (PL_is_functor(targ, FUNCTOR_colon2)) {
            if (!copy_to_dictionary(dict, targ, taux))
              return NULL;
            if (!PL_get_arg(2, t, t))
              return NULL;
          } else {
            return NULL;
          }
        }
        if (PL_is_functor(t, FUNCTOR_colon2)) {
          if (!copy_to_dictionary(dict, t, taux))
            return NULL;
        } else {
          return NULL;
        }
        return dict;
      } else if (fun == FUNCTOR_plus2) {
        term_t targ = PL_new_term_ref();
        PyObject *lhs, *rhs;

        if (!PL_get_arg(1, t, targ))
          return NULL;
        lhs = term_to_python(targ);
        if (!PL_get_arg(2, t, targ))
          return NULL;
        rhs = term_to_python(targ);
        if (PySequence_Check(lhs) && PySequence_Check(rhs)) {
          return PySequence_Concat(lhs, rhs);
        }
        if (!PyNumber_Check(lhs))
          return NULL;
        if (!PyNumber_Check(rhs))
          return NULL;
        return PyNumber_Add(lhs, rhs);
      } else if (fun == FUNCTOR_sub2) {
        term_t targ = PL_new_term_ref();
        PyObject *lhs, *rhs;

        if (!PL_get_arg(1, t, targ))
          return NULL;
        lhs = term_to_python(targ);
        if (!PyNumber_Check(lhs))
          return NULL;
        if (!PL_get_arg(2, t, targ))
          return NULL;
        rhs = term_to_python(targ);
        if (!PyNumber_Check(rhs))
          return NULL;
        return PyNumber_Subtract(lhs, rhs);
      } else if (fun == FUNCTOR_mul2) {
        term_t targ = PL_new_term_ref();
        PyObject *lhs, *rhs;

        if (!PL_get_arg(1, t, targ))
          return NULL;
        lhs = term_to_python(targ);
        if (!PL_get_arg(2, t, targ))
          return NULL;
        rhs = term_to_python(targ);
        if (PySequence_Check(lhs) && (
#if PY_MAJOR_VERSION < 3
                                         PyInt_Check(rhs) ||
#endif
                                         PyLong_Check(rhs))) {
          return PySequence_Repeat(lhs, get_p_int(rhs, 0));
        }
        if (!PyNumber_Check(lhs) + !PyNumber_Check(rhs))
          return NULL;
        return PyNumber_Multiply(lhs, rhs);
      } else if (fun == FUNCTOR_div2) {
        term_t targ = PL_new_term_ref();
        PyObject *lhs, *rhs;

        if (!PL_get_arg(1, t, targ))
          return NULL;
        lhs = term_to_python(targ);
        if (!PyNumber_Check(lhs))
          return NULL;
        if (!PL_get_arg(2, t, targ))
          return NULL;
        rhs = term_to_python(targ);
        if (!PyNumber_Check(rhs))
          return NULL;
#if PY_MAJOR_VERSION < 3
        return PyNumber_Divide(lhs, rhs);
#else
        return PyNumber_TrueDivide(lhs, rhs);
#endif
      } else if (fun == FUNCTOR_sqbrackets2) {
        //
        term_t targ = PL_new_term_ref(), trhs = PL_new_term_ref();
        PyObject *v;
        Py_ssize_t min, max;

        if (!PL_get_arg(1, t, targ))
          return NULL;
        v = term_to_python(targ);
        if (!PL_get_arg(2, t, targ) || !PL_get_list(targ, trhs, targ))
          return NULL;
        if (PL_is_functor(targ, FUNCTOR_colon2)) {
          if (!PL_get_arg(1, trhs, targ))
            return NULL;
          min = get_p_int(term_to_python(targ), 0);
          if (!PL_get_arg(2, trhs, targ))
            return NULL;
          if (PL_is_functor(targ, FUNCTOR_colon2)) {
            return NULL;
          }
          max = get_p_int(term_to_python(targ), PyObject_Size(v));
          if (!PySequence_Check(v))
            return NULL;
          return PySequence_GetSlice(v, min, max);
        }
      } else if (fun == FUNCTOR_dot2) {
        term_t tleft = PL_new_term_ref();
        PyObject *pArgs, *o;
        long i;
        int arity;
        atom_t name;

        o = NULL;
        while (fun == FUNCTOR_dot2) {
          if (!PL_get_arg(1, t, tleft))
            return FALSE;
          o = find_obj(o, tleft);
          if (!o)
            return FALSE;
          if (!PL_get_arg(2, t, t))
            return FALSE;
          if (!PL_get_functor(t, &fun))
            break;
        }
        if (!PL_get_name_arity(t, &name, &arity)) {
          return NULL;
        }
        if (!arity) {
          char *s;
          PyObject *pValue;

          if (!PL_get_atom_chars(t, &s))
            return NULL;
          if ((pValue = PyObject_GetAttrString(o, s)) == NULL) {
            PyErr_Print();
            return NULL;
          }
          return pValue;
        }
        o = PyObject_GetAttrString(o, PL_atom_chars(name));
        if (!o || !PyCallable_Check(o)) {
          return NULL;
        }
        pArgs = PyTuple_New(arity);
        for (i = 0; i < arity; i++) {
          PyObject *pArg;
          if (!PL_get_arg(i + 1, t, tleft))
            return NULL;
          /* ignore (_) */
          if (i == 0 && PL_is_variable(tleft)) {
            Py_DECREF(pArgs);
            pArgs = NULL;
          }
          pArg = term_to_python(tleft);
          if (pArg == NULL)
            return NULL;
          /* pArg reference stolen here: */
          PyTuple_SetItem(pArgs, i, pArg);
        }
        return PyObject_CallObject(o, pArgs);
      } else {
        atom_t name;
        int len;

        if (!PL_get_name_arity(t, &name, &len)) {
          return NULL;
        }
        if (name == ATOM_t) {
          term_t targ = PL_new_term_ref();
          PyObject *out;
          int i;

          out = PyTuple_New(len);
          if (!out)
            return NULL;
          for (i = 0; i < len; i++) {
            if (!PL_get_arg(i + 1, t, targ)) {
              return NULL;
            }
            PyErr_Clear();
            PyObject *oa = term_to_python(targ);
            PyObject *rc = PyTuple_SET_ITEM(out, i, oa);
            if (rc)
              PyErr_Print();
          }
          return out;
        }
      }
    }
    return NULL;
  }
  return NULL;
}

static foreign_t assign_to_symbol(term_t t, PyObject *e) {
  char *s;
  PyErr_Clear();
  if (!PL_get_atom_chars(t, &s)) {
    wchar_t *w;
    atom_t at;
    size_t len;
    PyObject *attr;

    if (!PL_get_atom(t, &at)) {
      return false;
    }
    if (!(w = PL_atom_wchars(at, &len)))
      return false;
    attr = PyUnicode_FromWideChar(w, wcslen(w));
    if (attr) {
      return PyObject_SetAttr(py_Main, attr, e) >= 0;
    } else {
      PyErr_Print();
      return false;
    }
  } else if (proper_ascii_string(s)) {
    return PyObject_SetAttrString(py_Main, s, e) >= 0;
  } else {
    PyObject *attr = PyUnicode_DecodeLatin1(s, strlen(s), NULL);
    if (!attr)
      return -1;
    return PyObject_SetAttr(py_Main, attr, e) >= 0;
  }
}

static int conj_size(term_t source) {
  if (PL_is_functor(source, FUNCTOR_comma2)) {
    term_t a1 = PL_new_term_ref(), a2 = PL_new_term_ref();
    if (PL_get_arg(1, source, a1) <= 0 || PL_get_arg(2, source, a2) <= 0)
      return -1;
    return conj_size(a1) + conj_size(a2);
  }
  return 1;
}

static int conj_copy(term_t target, PyObject *e, int pos) {
  if (PL_is_functor(target, FUNCTOR_comma2)) {
    term_t a1 = PL_new_term_ref(), a2 = PL_new_term_ref();
    if (PL_get_arg(1, target, a1) <= 0 || PL_get_arg(2, target, a2) <= 0)
      return -1;
    int p1 = conj_copy(a1, e, pos);
    return conj_copy(a2, e, p1);
  } else {
    assign_python(py_Main, target, PyTuple_GetItem(e, pos));
    return pos + 1;
  }
}

/** assign a tuple to something:
*/
static foreign_t python_assign_tuple(term_t t_lhs, term_t t_rhs) {
  PyObject *e = term_to_python(t_rhs);
  Py_ssize_t sz;
  functor_t f;
  if (!e || !PyTuple_Check(e)) {
    return -1;
  }
  sz = PyTuple_Size(e);
  switch (PL_term_type(t_lhs)) {
  case PL_VARIABLE:
    return PL_unify(t_lhs, t_rhs);
  case PL_ATOM:
    return assign_python(py_Main, t_rhs, e);
  case PL_TERM:
    if (PL_get_functor(t_lhs, &f)) {
      term_t targ = PL_new_term_ref();
      // assign a tuple to a tuple
      if (PL_functor_name(f) == ATOM_t && ((sz = PL_functor_arity(f)))) {
        int i;
        for (i = 0; i < sz; i++) {
          PL_get_arg(i + 1, t_lhs, targ);
          assign_python(py_Main, targ, PyTuple_GetItem(e, i));
        }
      } else if (PL_functor_name(f) == ATOM_comma) {
        int n = conj_size(t_lhs);
        if (n != sz)
          return -1;
        return conj_copy(t_lhs, e, 0);
      } else if (PL_functor_name(f) == ATOM_dot) { // vectors
        size_t len;
        term_t tail = PL_new_term_ref();

        PL_skip_list(t_lhs, tail, &len);
        if (!PL_get_nil(tail))
          return -1;
        term_t arg = tail;
        int i;

        for (i = 0; i < len; i++) {
          if (!PL_get_list(t_rhs, arg, t_rhs)) {
            return -1;
          }
          if (assign_python(py_Main, arg, PyTuple_GetItem(e, i)) < 0)
            return -1;
        }
      }
    }
  }
  return -1;
}

/**
 * assign_python  assigns the Python RHS to a Prolog term LHS, ie LHS = RHS
 *
 * @param root Python environment
 * @param t left hand side, in Prolog, may be
 *    - a Prolog variable, exports the term to Prolog, A <- RHS
 *    - Python variable A, A <- RHS
 *    - Python variable $A, A <- RHS
 *    - Python string "A", A <- RHS
 *    - Python array range
 * @param e the right-hand side
 *
 * @return -1 on failure.
                    *
                    * Note that this is an auxiliary routine to the Prolog
 *python_assign.
                    */
static int assign_python(PyObject *root, term_t t, PyObject *e) {
  switch (PL_term_type(t)) {
  case PL_VARIABLE:
    if (python_to_ptr(e, t))
      return 1;
    else
      return -1;
  case PL_ATOM:
    return assign_to_symbol(t, e);
  case PL_STRING:
  case PL_INTEGER:
  case PL_FLOAT:
    return -1;
  case PL_TERM:
    if (PL_is_list(t)) {
      return -1;
    } else {
      functor_t fun;

      if (!PL_get_functor(t, &fun))
        return -1;
      if (fun == FUNCTOR_dollar1) {
        if (!PL_get_arg(1, t, t))
          return -1;
        return assign_to_symbol(t, e);
      }
      if (fun == FUNCTOR_pointer1) {
        return -1;
      }
      if (fun == FUNCTOR_sqbrackets2) {
        term_t targ = PL_new_term_ref(), trhs = PL_new_term_ref();
        PyObject *lhs, *rhs;

        if (!PL_get_arg(1, t, targ))
          return -1;
        lhs = term_to_python(targ);
        if (!PL_get_arg(2, t, targ) || !PL_is_list(targ) ||
            !PL_get_list(targ, trhs, targ))
          return -1;
        if (PL_is_functor(trhs, FUNCTOR_dot2)) {
          Py_ssize_t left, right;
          if (!PL_get_arg(1, trhs, targ))
            return -1;
          left = get_p_int(term_to_python(targ), 0);
          if (!PL_get_arg(2, trhs, targ))
            return -1;
          right = get_p_int(term_to_python(targ), PyObject_Size(lhs));
          if (!PySequence_Check(lhs))
            return -1;
          return PySequence_SetSlice(lhs, left, right, e);
        } else {
          rhs = term_to_python(trhs);
          return PyObject_SetItem(lhs, rhs, e);
        }
        PL_reset_term_refs(targ);
      }
    }
  }
  return -1;
}

static foreign_t address_to_term(PyObject *pVal, term_t t) {
  term_t to = PL_new_term_ref(), t1 = PL_new_term_ref();
  PL_put_pointer(t1, (void *)pVal);
  PL_cons_functor(to, FUNCTOR_pointer1, t1);
  Py_INCREF(pVal);
  foreign_t rc = PL_unify(t, to);
  PL_reset_term_refs(to);
  return rc;
}

static foreign_t repr_term(const char *pVal, size_t sz, term_t t) {
  term_t to = PL_new_term_ref(), t1 = PL_new_term_ref();
  PL_put_string_chars(t1, pVal);
  PL_cons_functor(to, FUNCTOR_pointer1, t1);
  Py_INCREF(pVal);
  PL_reset_term_refs(to);
  return PL_unify(t, to);
}

static foreign_t python_to_ptr(PyObject *pVal, term_t t) {
  Py_IncRef(pVal);
  return address_to_term(pVal, t);
}

static foreign_t python_to_term(PyObject *pVal, term_t t) {
  if (pVal == Py_None) {
    return PL_unify_atom(t, ATOM_none);
  }
  if (PyBool_Check(pVal)) {
    if (PyObject_IsTrue(pVal)) {
      return PL_unify_atom(t, ATOM_true);
    } else {
      return PL_unify_atom(t, ATOM_false);
    }
  } else if (PyLong_Check(pVal)) {
    return PL_unify_int64(t, PyLong_AsLong(pVal));
#if PY_MAJOR_VERSION < 3
  } else if (PyInt_Check(pVal)) {
    return PL_unify_int64(t, PyInt_AsLong(pVal));
#endif
  } else if (PyFloat_Check(pVal)) {
    return PL_unify_float(t, PyFloat_AsDouble(pVal));
  } else if (PyComplex_Check(pVal)) {
    bool rc;
    term_t to = PL_new_term_ref(), t1 = PL_new_term_ref(),
           t2 = PL_new_term_ref();
    if (!PL_put_float(t1, PyComplex_RealAsDouble(pVal)) ||
        !PL_put_float(t2, PyComplex_ImagAsDouble(pVal)) ||
        !PL_cons_functor(to, FUNCTOR_complex2, t1, t2)) {
      rc = FALSE;
    } else {
      rc = PL_unify(t, to);
    }
    PL_reset_term_refs(to);
    return rc;
  } else if (PyUnicode_Check(pVal)) {
    atom_t tmp_atom;

#if PY_MAJOR_VERSION < 3
    Py_ssize_t sz = PyUnicode_GetSize(pVal) + 1;
    wchar_t *ptr = malloc(sizeof(wchar_t) * sz);
    sz = PyUnicode_AsWideChar((PyUnicodeObject *)pVal, ptr, sz - 1);
#else
    Py_ssize_t sz = PyUnicode_GetLength(pVal) + 1;
    wchar_t *ptr = malloc(sizeof(wchar_t) * sz);
    sz = PyUnicode_AsWideChar(pVal, ptr, sz);
#endif
    tmp_atom = PL_new_atom_wchars(sz, ptr);
    free(ptr);
    return PL_unify_atom(t, tmp_atom);
  } else if (PyByteArray_Check(pVal)) {
    atom_t tmp_atom = PL_new_atom(PyByteArray_AsString(pVal));
    return PL_unify_atom(t, tmp_atom);
#if PY_MAJOR_VERSION < 3
  } else if (PyString_Check(pVal)) {
    atom_t tmp_atom = PL_new_atom(PyString_AsString(pVal));
    return PL_unify_atom(t, tmp_atom);
#endif
  } else if (PyTuple_Check(pVal)) {
    Py_ssize_t i, sz = PyTuple_Size(pVal);
    functor_t f = PL_new_functor(ATOM_t, sz);
    if (!PL_unify_functor(t, f))
      return FALSE;
    for (i = 0; i < sz; i++) {
      term_t to = PL_new_term_ref();
      if (!PL_unify_arg(i + 1, t, to))
        return FALSE;
      if (!python_to_term(PyTuple_GetItem(pVal, i), to))
        return FALSE;
    }
    return TRUE;
  } else if (PyList_Check(pVal)) {
    term_t to = PL_new_term_ref();
    Py_ssize_t i, sz = PyList_GET_SIZE(pVal);

    for (i = 0; i < sz; i++) {
      if (!PL_unify_list(t, to, t) ||
          !python_to_term(PyList_GetItem(pVal, i), to))
        return FALSE;
    }
    return PL_unify_nil(t);
  } else if (PyDict_Check(pVal)) {
    Py_ssize_t pos = 0;
    term_t to = PL_new_term_ref(), ti = to;
    int left = PyDict_Size(pVal);
    PyObject *key, *value;

    while (PyDict_Next(pVal, &pos, &key, &value)) {
      term_t tkey = PL_new_term_ref(), tval = PL_new_term_ref(), tint,
             tnew = PL_new_term_ref();
      /* do something interesting with the values... */
      if (!python_to_term(key, tkey)) {
        return FALSE;
      }
      if (!python_to_term(value, tval)) {
        return FALSE;
      }
      /* reuse */
      tint = tkey;
      if (!PL_cons_functor(tint, FUNCTOR_colon2, tkey, tval)) {
        return FALSE;
      }
      if (--left) {
        if (!PL_cons_functor(tint, FUNCTOR_comma2, tint, tnew))
          return FALSE;
      }
      if (!PL_unify(ti, tint))
        return FALSE;
      ti = tnew;
    }
    PL_cons_functor(to, FUNCTOR_curly1, to);
    return PL_unify(t, to);
  } else {
    PyObject *pValR = PyObject_Repr(pVal);
    if (pValR == NULL)
      return address_to_term(pVal, t);
    Py_ssize_t sz = PyUnicode_GetSize(pValR) + 1;
#if PY_MAJOR_VERSION < 3
    char *s = malloc(sizeof(char) * sz);
    PyObject *us = PyUnicode_EncodeUTF8((const Py_UNICODE *)pValR, sz, NULL);
    PyString_AsStringAndSize(us, &s, &sz);
    foreign_t rc = repr_term(s, sz, t);
    free((void *)s);
    return rc;
#else
    // new interface
    char *s = PyUnicode_AsUTF8AndSize(pVal, &sz);
    return repr_term(s, sz, t);
#endif
  }
}

static foreign_t python_export(term_t t, term_t pl) {
  foreign_t rc = false;
  if (PL_is_functor(t, FUNCTOR_pointer1)) {
    void *ptr;
    term_t targ = PL_new_term_ref();

    if (!PL_get_arg(1, t, targ))
      return false;
    if (!PL_get_pointer(targ, &ptr))
      return false;
    Py_INCREF((PyObject *)ptr);
    /* return __main__,s */
    rc = python_to_term((PyObject *)ptr, pl);
  }
  return rc;
}

static int python_import(term_t mname, term_t mod) {
  char *s;
  size_t len;
  PyObject *pName, *pModule;

  if (PL_is_list(mname)) {
    char *s2;
    char str[256];
    term_t arg = PL_new_term_ref();
    if (!PL_get_arg(1, mname, arg) || !PL_get_atom_chars(arg, &s) ||
        !PL_get_arg(2, mname, mname) || !PL_get_arg(1, mname, arg) ||
        !PL_get_atom_chars(arg, &s2))
      return FALSE;
    strcpy(str, s);
    strcat(str, ".");
    strcat(str, s2);
    s = str;
  } else if (!PL_get_nchars(mname, &len, &s, CVT_ALL | CVT_EXCEPTION)) {
    return FALSE;
  }
#if PY_MAJOR_VERSION < 3
  pName = PyString_FromString(s);
#else
  printf("Module=%s\n", s);
  pName = PyUnicode_FromString(s);
#endif
  if (pName == NULL) {
    return FALSE;
  }
  pModule = PyImport_Import(pName);
  Py_DECREF(pName);
  if (pModule == NULL) {
#if EXTRA_MESSSAGES
    if (PyErr_Occurred())
      PyErr_Print();
    PyErr_Clear();
#endif
    return FALSE;
  }
  ActiveModules[active_modules++] = pModule;
  return python_to_ptr(pModule, mod);
}

static foreign_t python_f(term_t tmod, term_t fname, term_t tf) {
  char *s;
  size_t len;
  PyObject *pF, *pModule;

  /* if an atom, fetch again */
  if (PL_is_atom(tmod)) {
    PyObject *pName;

    if (!PL_get_nchars(fname, &len, &s, CVT_ALL | CVT_EXCEPTION)) {
      return FALSE;
    }
#if PY_MAJOR_VERSION < 3
    pName = PyString_FromString(s);
#else
    pName = PyUnicode_FromString(s);
#endif
    if (pName == NULL) {
      return FALSE;
    }
    pModule = PyImport_Import(pName);
  } else if (!(pModule = term_to_python(tmod)))
    return FALSE;
  if (!PL_get_nchars(fname, &len, &s, CVT_ALL | CVT_EXCEPTION)) {
    return FALSE;
  }
  pF = PyObject_GetAttrString(pModule, s);
  PyErr_Print();
  Py_DECREF(pModule);
  if (pF == NULL || !PyCallable_Check(pF)) {
    return FALSE;
  }
  printf("Module=%s ok\n", s);
  return python_to_ptr(pF, tf);
}

static foreign_t python_o(term_t tmod, term_t fname, term_t tf) {
  char *s;
  size_t len;
  PyObject *pO, *pModule;

  pModule = term_to_python(tmod);
  if (!PL_get_nchars(fname, &len, &s, CVT_ALL | CVT_EXCEPTION)) {
    return FALSE;
  }
  pO = PyObject_GetAttrString(pModule, s);
  if (pO == NULL) {
    return FALSE;
  }
  return python_to_ptr(pO, tf);
}

static foreign_t python_len(term_t tobj, term_t tf) {
  Py_ssize_t len;
  PyObject *o;

  o = term_to_python(tobj);
  if (o == NULL)
    return FALSE;
  len = PyObject_Length(o);
  return PL_unify_int64(tf, len);
}

static foreign_t python_dir(term_t tobj, term_t tf) {
  PyObject *dir;
  PyObject *o;

  o = term_to_python(tobj);
  if (o == NULL)
    return FALSE;
  dir = PyObject_Dir(o);
  return python_to_ptr(dir, tf);
}

static foreign_t python_index(term_t tobj, term_t tindex, term_t val) {
  PyObject *i;
  PyObject *o;
  PyObject *f;
  o = term_to_python(tobj);
  if (o == NULL)
    return false;
  if (!PySequence_Check(o))
    return false;
  i = term_to_python(tindex);
  if (i == NULL)
    return false;
#if PY_MAJOR_VERSION < 3
  f = PyObject_CallMethodObjArgs(o, PyString_FromString("getitem"), i);
#else
  f = PyObject_CallMethodObjArgs(o, PyUnicode_FromString("getitem"), i);
#endif
  return python_to_ptr(f, val);
}

static foreign_t python_is(term_t tobj, term_t tf) {
  PyObject *o;

  o = term_to_python(tobj);
  if (!o)
    return FALSE;

  return python_to_ptr(o, tf);
}

static foreign_t python_assign_item(term_t parent, term_t indx, term_t tobj) {
  PyObject *pF, *pI;

  PyObject *p;

  // get Scope ...
  pI = term_to_python(indx);
  // got Scope.Exp
  // get Scope ...
  p = term_to_python(parent);
  // Exp
  // get Scope ...
  pF = term_to_python(parent);
  // Exp
  if (!pI || !p) {
    return false;
  } else if (PyObject_SetItem(p, pI, pF)) {
    PyErr_Print();
    return FALSE;
  }
  Py_DecRef(pI);
  Py_DecRef(p);

  return true;
}

static foreign_t python_item(term_t parent, term_t indx, term_t tobj) {
  PyObject *pF, *pI;

  PyObject *p;

  // get Scope ...
  pI = term_to_python(indx);
  // got Scope.Exp
  // get Scope ...
  p = term_to_python(parent);
  // Exp
  if (!pI || !p) {
    return false;
  } else if ((pF = PyObject_GetItem(p, pI)) == NULL) {
    PyErr_Print();
    return FALSE;
  }
  Py_DecRef(pI);
  Py_DecRef(p);

  return address_to_term(pF, tobj);
}

static foreign_t python_slice(term_t parent, term_t indx, term_t tobj) {
  PyObject *pF, *pI;

  PyObject *p;

  // get Scope ...
  pI = term_to_python(indx);
  // got Scope.Exp
  // get Scope ...
  p = term_to_python(parent);
  // Exp
  if (!pI || !p) {
    return false;
  } else if ((pF = PySequence_GetSlice(p, 0, 0)) == NULL) {
    PyErr_Print();
    return FALSE;
  }
  Py_DecRef(pI);
  Py_DecRef(p);

  return address_to_term(pF, tobj);
}

static foreign_t python_apply(term_t tin, term_t targs, term_t keywds,
                              term_t tf) {
  PyObject *pF;
  PyObject *pArgs, *pKeywords;
  PyObject *pValue;
  int i, arity;
  atom_t aname;
  foreign_t out;
  term_t targ = PL_new_term_ref();

  pF = term_to_python(tin);
  if (pF == NULL) {
    return false;
  }
  if (PL_is_atom(targs)) {
    pArgs = NULL;
  } else {

    if (!PL_get_name_arity(targs, &aname, &arity)) {
      return FALSE;
    }
    if (arity == 1 && PL_get_arg(1, targs, targ) && PL_is_variable(targ)) {
      /* ignore (_) */
      pArgs = NULL;
    } else {

      pArgs = PyTuple_New(arity);
      if (!pArgs)
        return FALSE;
      for (i = 0; i < arity; i++) {
        PyObject *pArg;
        if (!PL_get_arg(i + 1, targs, targ))
          return FALSE;
        pArg = term_to_python(targ);
        if (pArg == NULL)
          return FALSE;
        /* pArg reference stolen here: */
        PyTuple_SetItem(pArgs, i, pArg);
      }
    }
  }
  if (PL_is_atom(keywds)) {
    pKeywords = NULL;
  } else {
    pKeywords = term_to_python(keywds);
  }
  if (PyCallable_Check(pF)) {
    pValue = PyEval_CallObjectWithKeywords(pF, pArgs, pKeywords);
    //   PyObject_Print(pF,stderr,0);fprintf(stderr, "\n");
    // PyObject_Print(pArgs,stderr,0);fprintf(stderr, " ");
    // PyObject_Print(pKeywords,stderr,0);fprintf(stderr, "\n");
    if (!pValue)
      PyErr_Print();
    else
      Py_IncRef(pValue);
  } else if (pArgs == NULL) {
    pValue = pF;

    if (pF) {
      Py_IncRef(pValue);
    }
  } else {
    PyErr_Print();
    return FALSE;
  }
  if (pArgs)
    Py_DECREF(pArgs);
  Py_DECREF(pF);
  if (pValue == NULL)
    return FALSE;
  out = python_to_ptr(pValue, tf);
  return out;
}

static foreign_t python_assign(term_t name, term_t exp) {
  PyObject *e = term_to_python(exp);

  if (e == NULL)
    return FALSE;
  return assign_python(py_Main, name, e) >= 0;
}

static foreign_t python_assign_field(term_t source, term_t name, term_t exp) {
  PyObject *e = term_to_python(exp), *root = term_to_python(source);

  if (e == NULL)
    return FALSE;
  return assign_python(root, name, e) >= 0;
}

static foreign_t python_builtin_eval(term_t caller, term_t dict, term_t out) {
  PyObject *pI, *pArgs, *pOut;
  PyObject *env;
  atom_t name;
  char *s;
  int i, arity;
  term_t targ = PL_new_term_ref();

  if ((env = py_Builtin) == NULL) {
    // no point in  even trying
    return false;
  }
  if (PL_get_name_arity(caller, &name, &arity)) {
    if (!(s = PL_atom_chars(name)))
      return false;
    if ((pI = PyObject_GetAttrString(env, s)) == NULL) {
      PyErr_Print();
      return false;
    }
  } else {
    // Prolog should make sure this never happens.
    return false;
  }
  pArgs = PyTuple_New(arity);
  for (i = 0; i < arity; i++) {
    PyObject *pArg;
    if (!PL_get_arg(i + 1, caller, targ))
      return FALSE;
    /* ignore (_) */
    if (i == 0 && PL_is_variable(targ)) {
      pArg = Py_None;
    } else {
      pArg = term_to_python(targ);
      if (pArg == NULL)
        return FALSE;
    }
    /* pArg reference stolen here: */
    if (PyTuple_SetItem(pArgs, i, pArg)) {
      PyErr_Print();
      return false;
    }
  }
  pOut = PyObject_CallObject(pI, pArgs);
  Py_DECREF(pArgs);
  Py_DECREF(pI);
  if (pOut == NULL) {
    PyErr_Print();
    return false;
  }
  return python_to_ptr(pOut, out);
}

static foreign_t python_access(term_t obj, term_t f, term_t out) {
  PyObject *o = term_to_python(obj), *pValue, *pArgs, *pF;
  atom_t name;
  char *s;
  int i, arity;
  term_t targ = PL_new_term_ref();

  if (o == NULL)
    return FALSE;
  if (PL_is_atom(f)) {
    if (!PL_get_atom_chars(f, &s))
      return FALSE;
    if ((pValue = PyObject_GetAttrString(o, s)) == NULL) {
      PyErr_Print();
      return FALSE;
    }
    return python_to_term(pValue, out);
  }
  if (!PL_get_name_arity(f, &name, &arity)) {
    return FALSE;
  }
  /* follow chains of the form a.b.c.d.e() */
  while (name == ATOM_dot && arity == 2) {
    term_t tleft = PL_new_term_ref();
    PyObject *lhs;

    if (!PL_get_arg(1, f, tleft))
      return FALSE;
    lhs = term_to_python(tleft);
    if ((o = PyObject_GetAttr(o, lhs)) == NULL) {
      PyErr_Print();
      return FALSE;
    }
    if (!PL_get_arg(2, f, f))
      return FALSE;
    if (!PL_get_name_arity(f, &name, &arity)) {
      return FALSE;
    }
  }
  s = PL_atom_chars(name);
  if (!s)
    return false;
  if ((pF = PyObject_GetAttrString(o, s)) == NULL) {
    PyErr_Print();
    return FALSE;
  }
  pArgs = PyTuple_New(arity);
  for (i = 0; i < arity; i++) {
    PyObject *pArg;
    if (!PL_get_arg(i + 1, f, targ))
      return FALSE;
    /* ignore (_) */
    if (i == 0 && PL_is_variable(targ)) {
      pArgs = Py_None;
    }
    pArg = term_to_python(targ);
    if (pArg == NULL)
      return FALSE;
    /* pArg reference stolen here: */
    PyTuple_SetItem(pArgs, i, pArg);
  }
  pValue = PyObject_CallObject(pF, pArgs);
  Py_DECREF(pArgs);
  Py_DECREF(pF);
  if (pValue == NULL) {
    return FALSE;
  }
  return python_to_term(pValue, out);
}

static foreign_t python_field(term_t parent, term_t att, term_t tobj) {
  PyObject *pF;
  atom_t name;
  char *s;
  int arity;

  if (!PL_get_name_arity(att, &name, &arity)) {
    return false;
  } else {
    PyObject *p;

    // got Scope.Exp
    // get Scope ...
    p = term_to_python(parent);
    // Exp
    if (!PL_get_name_arity(att, &name, &arity)) {
      return false;
    }
    s = PL_atom_chars(name);
    if (arity == 1 && !strcmp(s, "()")) {
      if (!PL_get_arg(1, att, att))
        return false;
      if (!PL_get_name_arity(att, &name, &arity)) {
        return false;
      }
      s = PL_atom_chars(name);
    }
    if (!s || !p) {
      return false;
    } else if ((pF = PyObject_GetAttrString(p, s)) == NULL) {
      PyErr_Clear();
      return FALSE;
    }
  }
  return address_to_term(pF, tobj);
}

static foreign_t python_main_module(term_t mod) {
  return address_to_term(py_Main, mod);
}

static foreign_t python_function(term_t tobj) {
  PyObject *obj = term_to_python(tobj);

  return PyFunction_Check(obj);
}

static foreign_t end_python(void) {
  Py_Finalize();

  return TRUE;
}

static foreign_t array_to_python_list(term_t addr, term_t type, term_t szt,
                                      term_t py) {
  void *src;
  Py_ssize_t sz, i;
  int is_float;

  if (!PL_get_pointer(addr, &src) || !PL_get_bool(type, &is_float) ||
      !PL_get_intptr(szt, &sz))
    return false;
  PyObject *list = PyList_New(sz);
  if (!list)
    return false;
  if (is_float) {
    double *v = (double *)src;
    for (i = 0; i < sz; i++) {
      PyObject *x = PyFloat_FromDouble(v[i]);
      PyList_SET_ITEM(list, i, x);
    }
  } else {
    YAP_Int *v = (YAP_Int *)src;
    for (i = 0; i < sz; i++) {
      PyObject *x = PyFloat_FromDouble(v[i]);
      PyList_SET_ITEM(list, i, x);
    }
  }
  if (PL_is_variable(py)) {
    return python_to_ptr(list, py);
  }
  return assign_to_symbol(py, list);
}

static foreign_t array_to_python_tuple(term_t addr, term_t type, term_t szt,
                                       term_t py) {
  void *src;
  Py_ssize_t sz, i;
  int is_float;

  if (!PL_get_pointer(addr, &src) || !PL_get_bool(type, &is_float) ||
      !PL_get_intptr(szt, &sz))
    return false;
  PyObject *list = PyTuple_New(sz);
  if (!list)
    return false;
  if (is_float) {
    double *v = (double *)src;

    for (i = 0; i < sz; i++) {
      PyObject *x;
      x = PyFloat_FromDouble(v[i]);
      if (PyTuple_SetItem(list, i, x)) {
        PyErr_Print();
        return FALSE;
      }
    }
  } else {
    int32_t *v = (int32_t *)src;
    PyObject *x;
    for (i = 0; i < sz; i++) {
#if PY_MAJOR_VERSION < 3
      x = PyInt_FromLong(v[i]);
#else
      x = PyLong_FromLong(v[i]);
#endif
      if (PyTuple_SetItem(list, i, x)) {
        PyErr_Print();
        return FALSE;
      }
    }
  }
  if (PL_is_variable(py)) {
    return python_to_ptr(list, py);
  }
  return assign_to_symbol(py, list);
}

static foreign_t array_to_python_view(term_t addr, term_t type, term_t szt,
                                      term_t colt, term_t py) {
  void *src;
  Py_ssize_t sz, rows;
  int is_float;
  Py_ssize_t shape[2];

  if (!PL_get_pointer(addr, &src) || !PL_get_bool(type, &is_float) ||
      !PL_get_intptr(szt, &sz) || !PL_get_intptr(colt, &rows))
    return false;
  Py_buffer buf;
  buf.buf = src;
  if (is_float) {
    buf.len = sz * sizeof(double);
    buf.itemsize = sizeof(double);
  } else {
    buf.len = sz * sizeof(YAP_Int);
    buf.itemsize = sizeof(YAP_Int);
  }
  buf.readonly = false;
  buf.format = NULL;
  buf.ndim = 2;
  buf.shape = shape;
  buf.strides = NULL;
  buf.suboffsets = NULL;
  PyObject *o = PyMemoryView_FromBuffer(&buf);
  if (!o) {
    PyErr_Print();
    return false;
  }
  if (PL_is_variable(py)) {
    return python_to_ptr(o, py);
  }
  return assign_to_symbol(py, o);
}

static foreign_t python_run_file(term_t file) {
  char *s;
  size_t len;
  char si[256];
  s = si;
  if (PL_get_nchars(file, &len, &s, CVT_ALL | CVT_EXCEPTION)) {
#if PY_MAJOR_VERSION < 3
    PyObject *PyFileObject = PyFile_FromString(si, "r");
    PyRun_SimpleFileEx(PyFile_AsFile(PyFileObject), "test.py", 1);
#else
    FILE *f = fopen(s, "r");
    if (f == NULL)
      return false;
    PyRun_SimpleFileEx(f, s, 1);
#endif
    return TRUE;
  }
  return false;
}

static foreign_t python_run_command(term_t cmd) {
  char *s;
  size_t len;
  char si[256];
  s = si;
  if (PL_get_nchars(cmd, &len, &s, CVT_ALL | CVT_EXCEPTION)) {
    PyRun_SimpleString(s);
  }
  return TRUE;
}

static foreign_t python_run_script(term_t cmd, term_t fun) {
  char si[256], sf[256];
  size_t len = 255, len1 = 255;
  PyObject *pName, *pModule, *pFunc;
  PyObject *pArgs = NULL, *pValue;
  char *s;

  s = si;
  if (PL_get_nchars(cmd, &len, &s, CVT_ALL | CVT_EXCEPTION) &&
      (s = sf) != NULL &&
      PL_get_nchars(fun, &len1, &s, CVT_ALL | CVT_EXCEPTION)) {

#if PY_MAJOR_VERSION < 3
    pName = PyString_FromString("rbm");
#else
    // asssumes UTF-8
    pName = PyUnicode_FromString("rbm");
#endif
    /* Error checking of pName left out */

    pModule = PyImport_Import(pName);
    Py_DECREF(pName);

    if (pModule != NULL) {
      pFunc = PyObject_GetAttrString(pModule, sf);
      /* pFunc is a new reference */

      if (pFunc && PyCallable_Check(pFunc)) {
        pValue = PyObject_CallObject(pFunc, pArgs);
        if (pValue != NULL) {
          Py_DECREF(pValue);
        } else {
          Py_DECREF(pFunc);
          Py_DECREF(pModule);
          PyErr_Print();
          fprintf(stderr, "Call failed\n");
          return false;
        }
      } else {
        if (PyErr_Occurred())
          PyErr_Print();
        fprintf(stderr, "Cannot find function \"%s\"\n", sf);
      }
      Py_XDECREF(pFunc);
      Py_DECREF(pModule);
    } else {
      PyErr_Print();
      fprintf(stderr, "Failed to load \"%s\"\n", s);
      return false;
    }
    return true;
  }
  return false;
}

static foreign_t python_builtin(term_t out) {
  return address_to_term(py_Builtin, out);
}

static foreign_t init_python(void) {
  char **argv;
  term_t t = PL_new_term_ref();
  YAP_Argv(&argv);
#if PY_MAJOR_VERSION < 3
  Py_SetProgramName(argv[0]);
#else
  wchar_t *buf = Py_DecodeLocale(argv[0], NULL);
  Py_SetProgramName(buf);
#endif
  Py_Initialize();
  py_Main = PyImport_AddModule("__main__");
  py_Builtin = PyImport_AddModule("__builtin__");
  // PL_put_atom( t, ATOM_builtin);
  // py_Builtin = term_to_python(t);
  PL_reset_term_refs(t);
  return TRUE;
}

install_t install_libpython(void);

install_t install_libpython(void) {
  FUNCTOR_dot2 = PL_new_functor(PL_new_atom("."), 2);
  // FUNCTOR_equal2 = PL_new_functor(PL_new_atom("="), 2);
  // FUNCTOR_boolop1 = PL_new_functor(PL_new_atom("@"), 1);
  ATOM_builtin = PL_new_atom("__builtin__");
  ATOM_comma = PL_new_atom(",");
  ATOM_colon = PL_new_atom(":");
  ATOM_true = PL_new_atom("true");
  ATOM_false = PL_new_atom("false");
  ATOM_dot = PL_new_atom(".");
  ATOM_none = PL_new_atom("none");
  ATOM_t = PL_new_atom("t");
  FUNCTOR_abs1 = PL_new_functor(PL_new_atom("abs"), 1);
  FUNCTOR_all1 = PL_new_functor(PL_new_atom("all"), 1);
  FUNCTOR_any1 = PL_new_functor(PL_new_atom("any"), 1);
  FUNCTOR_bin1 = PL_new_functor(PL_new_atom("bin"), 1);
  FUNCTOR_ord1 = PL_new_functor(PL_new_atom("ord"), 1);
  FUNCTOR_int1 = PL_new_functor(PL_new_atom("int"), 1);
  FUNCTOR_long1 = PL_new_functor(PL_new_atom("long"), 1);
  FUNCTOR_float1 = PL_new_functor(PL_new_atom("float"), 1);
  FUNCTOR_curly1 = PL_new_functor(PL_new_atom("{}"), 1);
  FUNCTOR_dollar1 = PL_new_functor(PL_new_atom("$"), 1);
  FUNCTOR_pointer1 = PL_new_functor(PL_new_atom("__obj__"), 1);
  FUNCTOR_dir1 = PL_new_functor(PL_new_atom("dir"), 1);
  FUNCTOR_iter1 = PL_new_functor(PL_new_atom("iter"), 1);
  FUNCTOR_iter2 = PL_new_functor(PL_new_atom("iter"), 2);
  FUNCTOR_len1 = PL_new_functor(PL_new_atom("len"), 1);
  FUNCTOR_range1 = PL_new_functor(PL_new_atom("range"), 1);
  FUNCTOR_range2 = PL_new_functor(PL_new_atom("range"), 2);
  FUNCTOR_range3 = PL_new_functor(PL_new_atom("range"), 3);
  FUNCTOR_sum1 = PL_new_functor(PL_new_atom("sum"), 1);
  FUNCTOR_complex2 = PL_new_functor(PL_new_atom("i"), 2);
  FUNCTOR_plus2 = PL_new_functor(PL_new_atom("+"), 2);
  FUNCTOR_sub2 = PL_new_functor(PL_new_atom("-"), 2);
  FUNCTOR_mul2 = PL_new_functor(PL_new_atom("*"), 2);
  FUNCTOR_div2 = PL_new_functor(PL_new_atom("/"), 2);
  FUNCTOR_hat2 = PL_new_functor(PL_new_atom("^"), 2);
  FUNCTOR_colon2 = PL_new_functor(PL_new_atom(":"), 2);
  FUNCTOR_comma2 = PL_new_functor(PL_new_atom(","), 2);
  FUNCTOR_equal2 = PL_new_functor(PL_new_atom("="), 2);
  FUNCTOR_sqbrackets2 = PL_new_functor(PL_new_atom("[]"), 2);

  PL_register_foreign("init_python", 0, init_python, 0);
  PL_register_foreign("end_python", 0, end_python, 0);
  PL_register_foreign("python_import", 2, python_import, 0);
  PL_register_foreign("python_f", 3, python_f, 0);
  PL_register_foreign("python_o", 3, python_o, 0);
  PL_register_foreign("python_len", 2, python_len, 0);
  PL_register_foreign("python_is", 2, python_is, 0);
  PL_register_foreign("python_dir", 2, python_dir, 0);
  PL_register_foreign("python_apply", 4, python_apply, 0);
  PL_register_foreign("python_index", 3, python_index, 0);
  PL_register_foreign("python_access", 3, python_access, 0);
  PL_register_foreign("python_field", 3, python_field, 0);
  PL_register_foreign("python_assign", 2, python_assign, 0);
  PL_register_foreign("python_assign_field", 3, python_assign_field, 0);
  PL_register_foreign("python_assign_tuple", 2, python_assign_tuple, 0);
  PL_register_foreign("python_export", 2, python_export, 0);
  PL_register_foreign("python_function", 1, python_function, 0);
  PL_register_foreign("python_slice", 4, python_slice, 0);
  PL_register_foreign("python_item", 3, python_item, 0);
  PL_register_foreign("python_assign_item", 3, python_assign_item, 0);
  PL_register_foreign("python_run_file", 1, python_run_file, 0);
  PL_register_foreign("python_run_command", 1, python_run_command, 0);
  PL_register_foreign("python_run_script", 2, python_run_script, 0);
  PL_register_foreign("python_main_module", 1, python_main_module, 0);
  PL_register_foreign("array_to_python_list", 4, array_to_python_list, 0);
  PL_register_foreign("array_to_python_tuple", 4, array_to_python_tuple, 0);
  PL_register_foreign("array_to_python_view", 5, array_to_python_view, 0);
  PL_register_foreign("python_builtin_eval", 3, python_builtin_eval, 0);
  PL_register_foreign("python_builtin", 1, python_builtin, 0);
}