[Python-checkins] r69188 - in python/branches/py3k: Include/code.h Include/object.h Misc/NEWS Objects/object.c Objects/typeobject.c

Sun Feb 1 14:59:23 CET 2009

Author: mark.dickinson
Date: Sun Feb 1 14:59:22 2009
New Revision: 69188
Log:
Issue #1717, continued: remove PyObject_Compare and Py_CmpToRich declarations
from object.h; don't inherit tp_compare slot on subclasses; and raise TypeError
when initializing a type that has a nonzero tp_compare slot. Fix up
comparison-related comments in object.c and code.h.
Modified:
 python/branches/py3k/Include/code.h
 python/branches/py3k/Include/object.h
 python/branches/py3k/Misc/NEWS
 python/branches/py3k/Objects/object.c
 python/branches/py3k/Objects/typeobject.c
Modified: python/branches/py3k/Include/code.h
==============================================================================

--- python/branches/py3k/Include/code.h	(original)
+++ python/branches/py3k/Include/code.h	Sun Feb 1 14:59:22 2009
@@ -20,7 +20,7 @@
 PyObject *co_varnames;	/* tuple of strings (local variable names) */
 PyObject *co_freevars;	/* tuple of strings (free variable names) */
 PyObject *co_cellvars; /* tuple of strings (cell variable names) */
- /* The rest doesn't count for hash/cmp */
+ /* The rest doesn't count for hash or comparisons */
 PyObject *co_filename;	/* unicode (where it was loaded from) */
 PyObject *co_name;		/* unicode (name, for reference) */
 int co_firstlineno;		/* first source line number */
Modified: python/branches/py3k/Include/object.h
==============================================================================
--- python/branches/py3k/Include/object.h	(original)
+++ python/branches/py3k/Include/object.h	Sun Feb 1 14:59:22 2009
@@ -426,10 +426,8 @@
 PyAPI_FUNC(PyObject *) PyObject_Str(PyObject *);
 PyAPI_FUNC(PyObject *) PyObject_ASCII(PyObject *);
 PyAPI_FUNC(PyObject *) PyObject_Bytes(PyObject *);
-PyAPI_FUNC(int) PyObject_Compare(PyObject *, PyObject *);
 PyAPI_FUNC(PyObject *) PyObject_RichCompare(PyObject *, PyObject *, int);
 PyAPI_FUNC(int) PyObject_RichCompareBool(PyObject *, PyObject *, int);
-PyAPI_FUNC(PyObject *) Py_CmpToRich(int op, int cmp);
 PyAPI_FUNC(PyObject *) PyObject_GetAttrString(PyObject *, const char *);
 PyAPI_FUNC(int) PyObject_SetAttrString(PyObject *, const char *, PyObject *);
 PyAPI_FUNC(int) PyObject_HasAttrString(PyObject *, const char *);
Modified: python/branches/py3k/Misc/NEWS
==============================================================================
--- python/branches/py3k/Misc/NEWS	(original)
+++ python/branches/py3k/Misc/NEWS	Sun Feb 1 14:59:22 2009
@@ -12,9 +12,11 @@
 Core and Builtins
 -----------------
 
-- Issue #1717: Remove builtin cmp() function, C-API functions
- PyObject_Cmp and PyObject_Compare, and the support function
- Py_CmpToRich.
+- Issue #1717: Removed builtin cmp() function, dropped tp_compare
+ slot, the C API functions PyObject_Compare and PyUnicode_Compare and
+ the type definition cmpfunc. The tp_compare slot is reserved for
+ future usage. An attempt to initialize a type with a nonzero
+ tp_compare slot will raise TypeError.
 
 - Issue #4707: round(x, n) now returns an integer if x is an integer.
 Previously it returned a float.
Modified: python/branches/py3k/Objects/object.c
==============================================================================
--- python/branches/py3k/Objects/object.c	(original)
+++ python/branches/py3k/Objects/object.c	Sun Feb 1 14:59:22 2009
@@ -500,35 +500,19 @@
 	return PyBytes_FromObject(v);
 }
 
-/* The new comparison philosophy is: we completely separate three-way
- comparison from rich comparison. That is, PyObject_Compare() and
- PyObject_Cmp() *just* use the tp_compare slot. And PyObject_RichCompare()
- and PyObject_RichCompareBool() *just* use the tp_richcompare slot.
+/* For Python 3.0.1 and later, the old three-way comparison has been
+ completely removed in favour of rich comparisons. PyObject_Compare() and
+ PyObject_Cmp() are gone, and the builtin cmp function no longer exists.
+ The old tp_compare slot will be renamed to tp_reserved, and should no
+ longer be used. Use tp_richcompare instead.
 
 See (*) below for practical amendments.
 
- IOW, only cmp() uses tp_compare; the comparison operators (==, !=, <=, <,
- >=, >) only use tp_richcompare. Note that list.sort() only uses <.
+ tp_richcompare gets called with a first argument of the appropriate type
+ and a second object of an arbitrary type. We never do any kind of
+ coercion.
 
- (And yes, eventually we'll rip out cmp() and tp_compare.)
-
- The calling conventions are different: tp_compare only gets called with two
- objects of the appropriate type; tp_richcompare gets called with a first
- argument of the appropriate type and a second object of an arbitrary type.
- We never do any kind of coercion.
-
- The return conventions are also different.
-
- The tp_compare slot should return a C int, as follows:
-
- -1 if a < b or if an exception occurred
- 0 if a == b
- +1 if a > b
-
- No other return values are allowed. PyObject_Compare() has the same
- calling convention.
-
- The tp_richcompare slot should return an object, as follows:
+ The tp_richcompare slot should return an object, as follows:
 
 NULL if an exception occurred
 NotImplemented if the requested comparison is not implemented
@@ -544,9 +528,6 @@
 comparing the object pointer (i.e. falling back to the base object
 implementation).
 
- - If three-way comparison is not implemented, it falls back on rich
- comparison (but not the other way around!).
-
 */
 
 /* Map rich comparison operators to their swapped version, e.g. LT <--> GT */
Modified: python/branches/py3k/Objects/typeobject.c
==============================================================================
--- python/branches/py3k/Objects/typeobject.c	(original)
+++ python/branches/py3k/Objects/typeobject.c	Sun Feb 1 14:59:22 2009
@@ -3662,7 +3662,7 @@
 		type->tp_setattr = base->tp_setattr;
 		type->tp_setattro = base->tp_setattro;
 	}
-	/* tp_compare see tp_richcompare */
+	/* tp_compare is ignored, see tp_richcompare */
 	COPYSLOT(tp_repr);
 	/* tp_hash see tp_richcompare */
 	COPYSLOT(tp_call);
@@ -3670,12 +3670,10 @@
 	{
 		/* Copy comparison-related slots only when
 		 not overriding them anywhere */
-		if (type->tp_compare == NULL &&
-		 type->tp_richcompare == NULL &&
+		if (type->tp_richcompare == NULL &&
 		 type->tp_hash == NULL &&
 		 !overrides_hash(type))
 		{
-			type->tp_compare = base->tp_compare;
 			type->tp_richcompare = base->tp_richcompare;
 			type->tp_hash = base->tp_hash;
 		}
@@ -3888,6 +3886,13 @@
 			goto error;
 	}
 
+	/* Check reserved slots */
+	if (type->tp_compare) {
+		PyErr_Format(PyExc_TypeError,
+			 "type %s has tp_compare",
+			 type->tp_name);
+	}
+
 	/* All done -- set the ready flag */
 	assert(type->tp_dict != NULL);
 	type->tp_flags =
