Issue #1717: remove the cmp builtin function, the C-API functions

PyObject_Cmp, PyObject_Compare, and various support functions.

Doc/c-api/object.rst

@@ -89,27 +89,6 @@ Object Protocol
    *opid*.
 
 
-.. cfunction:: int PyObject_Cmp(PyObject *o1, PyObject *o2, int *result)
-
-   .. index:: builtin: cmp
-
-   Compare the values of *o1* and *o2* using a routine provided by *o1*, if one
-   exists, otherwise with a routine provided by *o2*.  The result of the comparison
-   is returned in *result*.  Returns ``-1`` on failure.  This is the equivalent of
-   the Python statement ``result = cmp(o1, o2)``.
-
-
-.. cfunction:: int PyObject_Compare(PyObject *o1, PyObject *o2)
-
-   .. index:: builtin: cmp
-
-   Compare the values of *o1* and *o2* using a routine provided by *o1*, if one
-   exists, otherwise with a routine provided by *o2*.  Returns the result of the
-   comparison on success.  On error, the value returned is undefined; use
-   :cfunc:`PyErr_Occurred` to detect an error.  This is equivalent to the Python
-   expression ``cmp(o1, o2)``.
-
-
 .. cfunction:: PyObject* PyObject_Repr(PyObject *o)
 
    .. index:: builtin: repr

Include/abstract.h

@@ -228,29 +228,6 @@ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/
        */
 #define  PyObject_DelAttr(O,A) PyObject_SetAttr((O),(A),NULL)
 
-     PyAPI_FUNC(int) PyObject_Cmp(PyObject *o1, PyObject *o2, int *result);
-
-       /*
-	 Compare the values of o1 and o2 using a routine provided by
-	 o1, if one exists, otherwise with a routine provided by o2.
-	 The result of the comparison is returned in result.  Returns
-	 -1 on failure.  This is the equivalent of the Python
-	 statement: result=cmp(o1,o2).
-
-       */
-
-     /* Implemented elsewhere:
-
-     int PyObject_Compare(PyObject *o1, PyObject *o2);
-
-	 Compare the values of o1 and o2 using a routine provided by
-	 o1, if one exists, otherwise with a routine provided by o2.
-	 Returns the result of the comparison on success.  On error,
-	 the value returned is undefined. This is equivalent to the
-	 Python expression: cmp(o1,o2).
-
-       */
-
      /* Implemented elsewhere:
 
      PyObject *PyObject_Repr(PyObject *o);

Lib/test/test_builtin.py

@@ -220,9 +220,7 @@ class BuiltinTest(unittest.TestCase):
         self.assertRaises((OverflowError, ValueError), chr, 2**32)
 
     def test_cmp(self):
-        # uncomment the following line once cmp has been removed
+        self.assert_(not hasattr(builtins, "cmp"))
-        #self.assert_(not hasattr(builtins, "cmp"))
-        pass
 
     def test_compile(self):
         compile('print(1)\n', '', 'exec')

Misc/NEWS

@@ -12,6 +12,10 @@ What's New in Python 3.1 alpha 0
 Core and Builtins
 -----------------
 
+- Issue #1717: Remove builtin cmp() function, C-API functions
+  PyObject_Cmp and PyObject_Compare, and the support function
+  Py_CmpToRich.
+
 - Issue #4707: round(x, n) now returns an integer if x is an integer.
   Previously it returned a float.
 

Objects/abstract.c

@@ -27,22 +27,6 @@ null_error(void)
 
 /* Operations on any object */
 
-int
-PyObject_Cmp(PyObject *o1, PyObject *o2, int *result)
-{
-	int r;
-
-	if (o1 == NULL || o2 == NULL) {
-		null_error();
-		return -1;
-	}
-	r = PyObject_Compare(o1, o2);
-	if (PyErr_Occurred())
-		return -1;
-	*result = r;
-	return 0;
-}
-
 PyObject *
 PyObject_Type(PyObject *o)
 {

Objects/object.c

@@ -549,68 +549,6 @@ PyObject_Bytes(PyObject *v)
 
 */
 
-/* Forward */
-static PyObject *do_richcompare(PyObject *v, PyObject *w, int op);
-
-/* Perform a three-way comparison, raising TypeError if three-way comparison
-   is not supported.  */
-static int
-do_compare(PyObject *v, PyObject *w)
-{
-	cmpfunc f;
-	int ok;
-
-	if (v->ob_type == w->ob_type &&
-	    (f = v->ob_type->tp_compare) != NULL) {
-		return (*f)(v, w);
-	}
-
-	/* Now try three-way compare before giving up.  This is intentionally
-	   elaborate; if you have a it will raise TypeError if it detects two
-	   objects that aren't ordered with respect to each other. */
-	ok = PyObject_RichCompareBool(v, w, Py_LT);
-	if (ok < 0)
-		return -1; /* Error */
-	if (ok)
-		return -1; /* Less than */
-	ok = PyObject_RichCompareBool(v, w, Py_GT);
-	if (ok < 0)
-		return -1; /* Error */
-	if (ok)
-		return 1; /* Greater than */
-	ok = PyObject_RichCompareBool(v, w, Py_EQ);
-	if (ok < 0)
-		return -1; /* Error */
-	if (ok)
-		return 0; /* Equal */
-
-	/* Give up */
-	PyErr_Format(PyExc_TypeError,
-		     "unorderable types: '%.100s' != '%.100s'",
-		     v->ob_type->tp_name,
-		     w->ob_type->tp_name);
-	return -1;
-}
-
-/* Perform a three-way comparison.  This wraps do_compare() with a check for
-   NULL arguments and a recursion check. */
-int
-PyObject_Compare(PyObject *v, PyObject *w)
-{
-	int res;
-
-	if (v == NULL || w == NULL) {
-		if (!PyErr_Occurred())
-			PyErr_BadInternalCall();
-		return -1;
-	}
-	if (Py_EnterRecursiveCall(" in cmp"))
-		return -1;
-	res = do_compare(v, w);
-	Py_LeaveRecursiveCall();
-	return res < 0 ? -1 : res;
-}
-
 /* Map rich comparison operators to their swapped version, e.g. LT <--> GT */
 int _Py_SwappedOp[] = {Py_GT, Py_GE, Py_EQ, Py_NE, Py_LT, Py_LE};
 
@@ -715,44 +653,6 @@ PyObject_RichCompareBool(PyObject *v, PyObject *w, int op)
 	return ok;
 }
 
-/* Turn the result of a three-way comparison into the result expected by a
-   rich comparison. */
-PyObject *
-Py_CmpToRich(int op, int cmp)
-{
-	PyObject *res;
-	int ok;
-
-	if (PyErr_Occurred())
-		return NULL;
-	switch (op) {
-	case Py_LT:
-		ok = cmp <  0;
-		break;
-	case Py_LE:
-		ok = cmp <= 0;
-		break;
-	case Py_EQ:
-		ok = cmp == 0;
-		break;
-	case Py_NE:
-		ok = cmp != 0;
-		break;
-	case Py_GT:
-		ok = cmp >  0;
-		break;
-	case Py_GE:
-		ok = cmp >= 0;
-		break;
-	default:
-		PyErr_BadArgument();
-		return NULL;
-	}
-	res = ok ? Py_True : Py_False;
-	Py_INCREF(res);
-	return res;
-}
-
 /* Set of hash utility functions to help maintaining the invariant that
 	if a==b then hash(a)==hash(b)
 

Objects/typeobject.c

@@ -2897,7 +2897,7 @@ same_slots_added(PyTypeObject *a, PyTypeObject *b)
 	slots_a = ((PyHeapTypeObject *)a)->ht_slots;
 	slots_b = ((PyHeapTypeObject *)b)->ht_slots;
 	if (slots_a && slots_b) {
-		if (PyObject_Compare(slots_a, slots_b) != 0)
+		if (PyObject_RichCompareBool(slots_a, slots_b, Py_EQ) != 1)
 			return 0;
 		size += sizeof(PyObject *) * PyTuple_GET_SIZE(slots_a);
 	}

Python/bltinmodule.c

@@ -493,25 +493,6 @@ PyDoc_STR(
 ;
 
 
-static PyObject *
-builtin_cmp(PyObject *self, PyObject *args)
-{
-	PyObject *a, *b;
-	int c;
-
-	if (!PyArg_UnpackTuple(args, "cmp", 2, 2, &a, &b))
-		return NULL;
-	if (PyObject_Cmp(a, b, &c) < 0)
-		return NULL;
-	return PyLong_FromLong((long)c);
-}
-
-PyDoc_STRVAR(cmp_doc,
-"cmp(x, y) -> integer\n\
-\n\
-Return negative if x<y, zero if x==y, positive if x>y.");
-
-
 static char *
 source_as_string(PyObject *cmd, char *funcname, char *what)
 {
@@ -2230,7 +2211,6 @@ static PyMethodDef builtin_methods[] = {
  	{"ascii",	builtin_ascii,      METH_O, ascii_doc},
 	{"bin",		builtin_bin,	    METH_O, bin_doc},
  	{"chr",		builtin_chr,        METH_VARARGS, chr_doc},
- 	{"cmp",		builtin_cmp,        METH_VARARGS, cmp_doc},
  	{"compile",	(PyCFunction)builtin_compile,    METH_VARARGS | METH_KEYWORDS, compile_doc},
  	{"delattr",	builtin_delattr,    METH_VARARGS, delattr_doc},
  	{"dir",		builtin_dir,        METH_VARARGS, dir_doc},