Add __bool__ to None

Objects/object.c

 
 /* Generic object operations; and implementation of None */
 
 #include "Python.h"
 #include "frameobject.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
@@ skipping 1123 matching lines @@
 /* Test a value used as condition, e.g., in a for or if statement.
    Return -1 if an error occurred */
 
 int
 PyObject_IsTrue(PyObject *v)
 {
     Py_ssize_t res;
     if (v == Py_True)
         return 1;
     if (v == Py_False)
-        return 0;
-    if (v == Py_None)
         return 0;
     else if (v->ob_type->tp_as_number != NULL &&
              v->ob_type->tp_as_number->nb_bool != NULL)
         res = (*v->ob_type->tp_as_number->nb_bool)(v);
     else if (v->ob_type->tp_as_mapping != NULL &&
              v->ob_type->tp_as_mapping->mp_length != NULL)
         res = (*v->ob_type->tp_as_mapping->mp_length)(v);
     else if (v->ob_type->tp_as_sequence != NULL &&
              v->ob_type->tp_as_sequence->sq_length != NULL)
         res = (*v->ob_type->tp_as_sequence->sq_length)(v);
@@ skipping 114 matching lines @@
 /* ARGUSED */
 static void
 none_dealloc(PyObject* ignore)
 {
     /* This should never get called, but we also don't want to SEGV if
      * we accidentally decref None out of existence.
      */
     Py_FatalError("deallocating None");
 }
 
+static int
+none_bool(PyObject *v)
+{
+    return 0;
+}
+
+static PyNumberMethods none_as_number = {
+    0,                          /* nb_add */
+    0,                          /* nb_subtract */
+    0,                          /* nb_multiply */
+    0,                          /* nb_remainder */
+    0,                          /* nb_divmod */
+    0,                          /* nb_power */
+    0,                          /* nb_negative */
+    0,                          /* nb_positive */
+    0,                          /* nb_absolute */
+    (inquiry)none_bool,         /* nb_bool */
+    0,                          /* nb_invert */
+    0,                          /* nb_lshift */
+    0,                          /* nb_rshift */
+    0,                          /* nb_and */
+    0,                          /* nb_xor */
+    0,                          /* nb_or */
+    0,                          /* nb_int */
+    0,                          /* nb_reserved */
+    0,                          /* nb_float */
+    0,                          /* nb_inplace_add */
+    0,                          /* nb_inplace_subtract */
+    0,                          /* nb_inplace_multiply */
+    0,                          /* nb_inplace_remainder */
+    0,                          /* nb_inplace_power */
+    0,                          /* nb_inplace_lshift */
+    0,                          /* nb_inplace_rshift */
+    0,                          /* nb_inplace_and */
+    0,                          /* nb_inplace_xor */
+    0,                          /* nb_inplace_or */
+    0,                          /* nb_floor_divide */
+    0,                          /* nb_true_divide */
+    0,                          /* nb_inplace_floor_divide */
+    0,                          /* nb_inplace_true_divide */
+    0,                          /* nb_index */
+};
 
 static PyTypeObject PyNone_Type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     "NoneType",
     0,
     0,
     none_dealloc,       /*tp_dealloc*/ /*never called*/
     0,                  /*tp_print*/
     0,                  /*tp_getattr*/
     0,                  /*tp_setattr*/
     0,                  /*tp_reserved*/
     none_repr,          /*tp_repr*/
-    0,                  /*tp_as_number*/
+    &none_as_number,    /*tp_as_number*/
     0,                  /*tp_as_sequence*/
     0,                  /*tp_as_mapping*/
     0,                  /*tp_hash */
 };
 
 PyObject _Py_NoneStruct = {
   _PyObject_EXTRA_INIT
   1, &PyNone_Type
 };
 
@@ skipping 429 matching lines @@
 _Py_Dealloc(PyObject *op)
 {
     _Py_INC_TPFREES(op) _Py_COUNT_ALLOCS_COMMA
     (*Py_TYPE(op)->tp_dealloc)(op);
 }
 #endif
 
 #ifdef __cplusplus
 }
 #endif