Merged revisions 79674 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r79674 | mark.dickinson | 2010-04-03 15:05:10 +0100 (Sat, 03 Apr 2010) | 3 lines
Issue #8300: Let struct.pack use __index__ to convert and pack non-integers.
Based on a patch by Meador Inge.
........
diff --git a/Doc/library/struct.rst b/Doc/library/struct.rst
index bee154f..ee949d9 100644
--- a/Doc/library/struct.rst
+++ b/Doc/library/struct.rst
@@ -119,6 +119,15 @@
the platform C compiler supports C :ctype:`long long`, or, on Windows,
:ctype:`__int64`. They are always available in standard modes.
+(4)
+ When attempting to pack a non-integer using any of the integer conversion
+ codes, if the non-integer has a :meth:`__index__` method then that method is
+ called to convert the argument to an integer before packing.
+
+ .. versionchanged:: 3.2
+ Use of the :meth:`__index__` method for non-integers is new in 3.2.
+
+
A format character may be preceded by an integral repeat count. For example,
the format string ``'4h'`` means exactly the same as ``'hhhh'``.
diff --git a/Lib/test/test_struct.py b/Lib/test/test_struct.py
index 39ccb27..3d67abd 100644
--- a/Lib/test/test_struct.py
+++ b/Lib/test/test_struct.py
@@ -282,6 +282,23 @@
struct.pack, self.format,
NotAnInt)
+ # Objects with an '__index__' method should be allowed
+ # to pack as integers.
+ class Indexable(object):
+ def __init__(self, value):
+ self._value = value
+
+ def __index__(self):
+ return self._value
+
+ for obj in (Indexable(0), Indexable(10), Indexable(17),
+ Indexable(42), Indexable(100), Indexable(127)):
+ try:
+ struct.pack(format, obj)
+ except:
+ self.fail("integer code pack failed on object "
+ "with '__index__' method")
+
for code in integer_codes:
for byteorder in byteorders:
if (byteorder in ('', '@') and code in ('q', 'Q') and
diff --git a/Misc/NEWS b/Misc/NEWS
index a1465d7..a15fa91 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -879,6 +879,11 @@
Extension Modules
-----------------
+- Issue #8300: When passing a non-integer argument to struct.pack with any
+ integer format code, struct.pack first attempts to convert the non-integer
+ using its __index__ method. If that method is non-existent or raises
+ TypeError it goes on to try the __int__ method, as described below.
+
- Issue #8142: Update libffi to the 3.0.9 release.
- Issue #6949: Allow the _dbm extension to be built with db 4.8.x.
diff --git a/Modules/_struct.c b/Modules/_struct.c
index 43321a4..e21487d 100644
--- a/Modules/_struct.c
+++ b/Modules/_struct.c
@@ -97,12 +97,27 @@
{
assert(v != NULL);
if (!PyLong_Check(v)) {
- PyErr_SetString(StructError,
- "required argument is not an integer");
- return NULL;
+ /* Not an integer; try to use __index__ to convert. */
+ if (PyIndex_Check(v)) {
+ v = PyNumber_Index(v);
+ if (v == NULL)
+ return NULL;
+ if (!PyLong_Check(v)) {
+ PyErr_SetString(PyExc_TypeError,
+ "__index__ method "
+ "returned non-integer");
+ return NULL;
+ }
+ }
+ else {
+ PyErr_SetString(StructError,
+ "required argument is not an integer");
+ return NULL;
+ }
}
+ else
+ Py_INCREF(v);
- Py_INCREF(v);
return v;
}