This introduces:
- A new operator // that means floor division (the kind of division
where 1/2 is 0).
- The "future division" statement ("from __future__ import division)
which changes the meaning of the / operator to implement "true
division" (where 1/2 is 0.5).
- New overloadable operators __truediv__ and __floordiv__.
- New slots in the PyNumberMethods struct for true and floor division,
new abstract APIs for them, new opcodes, and so on.
I emphasize that without the future division statement, the semantics
of / will remain unchanged until Python 3.0.
Not yet implemented are warnings (default off) when / is used with int
or long arguments.
This has been on display since 7/31 as SF patch #443474.
Flames to /dev/null.
For rich comparisons, use instance_getattr2() when possible to avoid
the expense of setting an AttributeError. Also intern the name_op[]
table and use the interned strings rather than creating a new string
and interning it each time through.
safely together and don't duplicate logic (the common logic was factored
out into new private API function _PySequence_IterContains()).
Visible change:
some_complex_number in some_instance
no longer blows up if some_instance has __getitem__ but neither
__contains__ nor __iter__. test_iter changed to ensure that remains true.
need to be specified in the type structures independently. The flag
exists only for binary compatibility.
This is a "source cleanliness" issue and introduces no behavioral changes.
sees it (test_iter.py is unchanged).
- Added a tp_iternext slot, which calls the iterator's next() method;
this is much faster for built-in iterators over built-in types
such as lists and dicts, speeding up pybench's ForLoop with about
25% compared to Python 2.1. (Now there's a good argument for
iterators. ;-)
- Renamed the built-in sequence iterator SeqIter, affecting the C API
functions for it. (This frees up the PyIter prefix for generic
iterator operations.)
- Added PyIter_Check(obj), which checks that obj's type has a
tp_iternext slot and that the proper feature flag is set.
- Added PyIter_Next(obj) which calls the tp_iternext slot. It has a
somewhat complex return condition due to the need for speed: when it
returns NULL, it may not have set an exception condition, meaning
the iterator is exhausted; when the exception StopIteration is set
(or a derived exception class), it means the same thing; any other
exception means some other error occurred.
new slot tp_iter in type object, plus new flag Py_TPFLAGS_HAVE_ITER
new C API PyObject_GetIter(), calls tp_iter
new builtin iter(), with two forms: iter(obj), and iter(function, sentinel)
new internal object types iterobject and calliterobject
new exception StopIteration
new opcodes for "for" loops, GET_ITER and FOR_ITER (also supported by dis.py)
new magic number for .pyc files
new special method for instances: __iter__() returns an iterator
iteration over dictionaries: "for x in dict" iterates over the keys
iteration over files: "for x in file" iterates over lines
TODO:
documentation
test suite
decide whether to use a different way to spell iter(function, sentinal)
decide whether "for key in dict" is a good idea
use iterators in map/filter/reduce, min/max, and elsewhere (in/not in?)
speed tuning (make next() a slot tp_next???)
must now initialize the extra field used by the weak-ref machinery to
NULL themselves, to avoid having to require PyObject_INIT() to check
if the type supports weak references and do it there. This causes less
work to be done for all objects (the type object does not need to be
consulted to check for the Py_TPFLAGS_HAVE_WEAKREFS bit).
set a function attribute on a method (either bound or unbound). This
reverts to Python 2.0 behavior that no attributes of the method are
writable, but provides a more informative error message.
earlier coercion changes, not by rich comparisons. When a coercion
function returns 1 (meaning it cannot do it), it should not INCREF the
arguments. When no __coerce__() method was found, instance_coerce()
originally returned 0, pretending it did it. Neil changed the return
value to 1, more accurately reflecting that it didn't do anything, but
forgot to take out the two INCREF calls.
- Got rid of instance_cmp(); refactored instance_compare().
- Added instance_richcompare() which calls __lt__() etc.
Some unrelated stuff mixed in:
- Aligned comments in various large struct initializers.
- Better test to avoid recursion if __coerce__ returns self as the
first argument (this is an unrelated fix by Neil Schemenauer!).
- Style nit: don't use Py_DECREF(Py_NotImplemented); use
Py_DECREF(result) -- it just looks better. :-)
Closes SF patch #103123.
funcobject.h:
PyFunctionObject: add the func_dict slot.
funcobject.c:
PyFunction_New(): Initialize the func_dict slot to NULL.
func_getattr(): Rename to func_getattro() and change the
signature. It's more efficient to use attro methods and dig the C
string out than it is to re-convert a C string to a PyString.
Also, add support for getting the __dict__ (a.k.a. func_dict)
attribute, and for getting an arbitrary function attribute.
func_setattr(): Rename to func_setattro() and change the signature
for the same reason. Also add support for setting __dict__
(a.k.a. func_dict) and any arbitrary function attribute.
func_dealloc(): Be sure to DECREF the func_dict slot.
func_traverse(): Be sure to traverse func_dict too.
PyFunction_Type: make the necessary func_?etattro() changes.
classobject.c:
instancemethod_memberlist: Add __dict__
instancemethod_setattro(): New method to set arbitrary attributes
on methods (really the underlying im_func). Raise TypeError when
the instance is bound or when you're trying to set one of the
reserved im_* attributes.
instancemethod_getattr(): Renamed to instancemethod_getattro()
since that's what it really is. Also, added support fo getting
arbitrary attributes through the im_func.
PyMethod_Type: Do the ?etattr{,o} dance.
that Py_INCREF boosts global _Py_RefTotal when Py_REF_DEBUG is defined
but Py_TRACE_REFS isn't.
There are, IMO, way too many preprocessor gimmicks in use for refcount
debugging (at least 3 distinct true/false symbols, but not all 8 combos
are supported by the code, etc etc), and no coherent documentation of
this stuff -- 'twas too painful to track this one down.
to integer types (i.e. Py_uintptr_t, our spelling of C9X's uintptr_t).
ANSI specifies that pointer compares other than == and != to
non-related structures are undefined. This quiets an Insure
portability warning.
is no __getslice__ available. Also does the same for C extension types.
Includes rudimentary documentation (it could use a cross reference to the
section on slice objects, I couldn't figure out how to do that) and a test
suite for all Python __hooks__ I could think of, including the new
behaviour.
comments, docstrings or error messages. I fixed two minor things in
test_winreg.py ("didn't" -> "Didn't" and "Didnt" -> "Didn't").
There is a minor style issue involved: Guido seems to have preferred English
grammar (behaviour, honour) in a couple places. This patch changes that to
American, which is the more prominent style in the source. I prefer English
myself, so if English is preferred, I'd be happy to supply a patch myself ;)
The common technique for printing out a pointer has been to cast to a long
and use the "%lx" printf modifier. This is incorrect on Win64 where casting
to a long truncates the pointer. The "%p" formatter should be used instead.
The problem as stated by Tim:
> Unfortunately, the C committee refused to define what %p conversion "looks
> like" -- they explicitly allowed it to be implementation-defined. Older
> versions of Microsoft C even stuck a colon in the middle of the address (in
> the days of segment+offset addressing)!
The result is that the hex value of a pointer will maybe/maybe not have a 0x
prepended to it.
Notes on the patch:
There are two main classes of changes:
- in the various repr() functions that print out pointers
- debugging printf's in the various thread_*.h files (these are why the
patch is large)
Closes SourceForge patch #100505.
errors in some of the hash algorithms. For exmaple, in float_hash and
complex_hash a certain part of the value is not included in the hash
calculation. See Tim's, Guido's, and my discussion of this on
python-dev in May under the title "fix float_hash and complex_hash for
64-bit *nix"
(2) The hash algorithms that use pointers (e.g. func_hash, code_hash)
are universally not correct on Win64 (they assume that sizeof(long) ==
sizeof(void*))
As well, this patch significantly cleans up the hash code. It adds the
two function _Py_HashDouble and _PyHash_VoidPtr that the various
hashing routine are changed to use.
These help maintain the hash function invariant: (a==b) =>
(hash(a)==hash(b))) I have added Lib/test/test_hash.py and
Lib/test/output/test_hash to test this for some cases.
Avoid calling the dealloc function, previously triggered with
DECREF(inst). This caused a segfault in PyDict_GetItem, called with a
NULL dict, whenever inst->in_dict fails under low-memory conditions.
Guido van Rossum
Tim Peters
Jeremy Hylton
Fred Drake
Barry Warsaw
Neil Schemenauer
Thomas Wouters
Skip Montanaro