This patch implements what we have discussed on python-dev late in
September: str(obj) and unicode(obj) should behave similar, while
the old behaviour is retained for unicode(obj, encoding, errors).
The patch also adds a new feature with which objects can provide
unicode(obj) with input data: the __unicode__ method. Currently no
new tp_unicode slot is implemented; this is left as option for the
future.
Note that PyUnicode_FromEncodedObject() no longer accepts Unicode
objects as input. The API name already suggests that Unicode
objects do not belong in the list of acceptable objects and the
functionality was only needed because
PyUnicode_FromEncodedObject() was being used directly by
unicode(). The latter was changed in the discussed way:
* unicode(obj) calls PyObject_Unicode()
* unicode(obj, encoding, errors) calls PyUnicode_FromEncodedObject()
One thing left open to discussion is whether to leave the
PyUnicode_FromObject() API as a thin API extension on top of
PyUnicode_FromEncodedObject() or to turn it into a (macro) alias
for PyObject_Unicode() and deprecate it. Doing so would have some
surprising consequences though, e.g. u"abc" + 123 would turn out
as u"abc123"...
[Marc-Andre didn't have time to check this in before the deadline. I
hope this is OK, Marc-Andre! You can still make changes and commit
them on the trunk after the branch has been made, but then please mail
Barry a context diff if you want the change to be merged into the
2.2b1 release branch. GvR]
object.c, PyObject_Str: Don't try to optimize anything except exact
string objects here; in particular, let str subclasses go thru tp_str,
same as non-str objects. This allows overrides of tp_str to take
effect.
stringobject.c:
+ string_print (str's tp_print): If the argument isn't an exact string
object, get one from PyObject_Str.
+ string_str (str's tp_str): Make a genuine-string copy of the object if
it's of a proper str subclass type. str() applied to a str subclass
that doesn't override __str__ ends up here.
test_descr.py: New str_of_str_subclass() test.
This simplifies the rounding in _PyObject_VAR_SIZE, allows to restore the
pre-rounding calling sequence, and allows some nice little simplifications
in its callers. I'm still making it return a size_t, though.
As Guido suggested, this makes the new subclassing code substantially
simpler. But the mechanics of doing it w/ C macro semantics are a mess,
and _PyObject_VAR_SIZE has a new calling sequence now.
Question: The PyObject_NEW_VAR macro appears to be part of the public API.
Regardless of what it expands to, the notion that it has to round up the
memory it allocates is new, and extensions containing the old
PyObject_NEW_VAR macro expansion (which was embedded in the
PyObject_NEW_VAR expansion) won't do this rounding. But the rounding
isn't actually *needed* except for new-style instances with dict pointers
after a variable-length blob of embedded data. So my guess is that we do
not need to bump the API version for this (as the rounding isn't needed
for anything an extension can do unless it's recompiled anyway). What's
your guess?
+ Use the _PyObject_VAR_SIZE macro to compute object size.
+ Break the computation into lines convenient for debugger inspection.
+ Speed the round-up-to-pointer-size computation.
hack, and it's even more disgusting than a PyInstance_Check() call.
If the tp_compare slot is the slot used for overrides in Python,
it's always called.
Add some tests that show what should work too.
and are lists, and then just the string elements (if any)).
There are good and bad reasons for this. The good reason is to support
dir() "like before" on objects of extension types that haven't migrated
to the class introspection API yet. The bad reason is that Python's own
method objects are such a type, and this is the quickest way to get their
im_self etc attrs to "show up" via dir(). It looks much messier to move
them to the new scheme, as their current getattr implementation presents
a view of their attrs that's a untion of their own attrs plus their
im_func's attrs. In particular, methodobject.__dict__ actually returns
methodobject.im_func.__dict__, and if that's important to preserve it
doesn't seem to fit the class introspection model at all.
- use PyModule_Check() instead of PyObject_TypeCheck(), now we can.
- don't assert that the __dict__ gotten out of a module is always
a dictionary; check its type, and raise an exception if it's not.
PEP 238. Changes:
- add a new flag variable Py_DivisionWarningFlag, declared in
pydebug.h, defined in object.c, set in main.c, and used in
{int,long,float,complex}object.c. When this flag is set, the
classic division operator issues a DeprecationWarning message.
- add a new API PyRun_SimpleStringFlags() to match
PyRun_SimpleString(). The main() function calls this so that
commands run with -c can also benefit from -Dnew.
- While I was at it, I changed the usage message in main() somewhat:
alphabetized the options, split it in *four* parts to fit in under
512 bytes (not that I still believe this is necessary -- doc strings
elsewhere are much longer), and perhaps most visibly, don't display
the full list of options on each command line error. Instead, the
full list is only displayed when -h is used, and otherwise a brief
reminder of -h is displayed. When -h is used, write to stdout so
that you can do `python -h | more'.
Notes:
- I don't want to use the -W option to control whether the classic
division warning is issued or not, because the machinery to decide
whether to display the warning or not is very expensive (it involves
calling into the warnings.py module). You can use -Werror to turn
the warnings into exceptions though.
- The -Dnew option doesn't select future division for all of the
program -- only for the __main__ module. I don't know if I'll ever
change this -- it would require changes to the .pyc file magic
number to do it right, and a more global notion of compiler flags.
- You can usefully combine -Dwarn and -Dnew: this gives the __main__
module new division, and warns about classic division everywhere
else.
- Do not compile unicodeobject, unicodectype, and unicodedata if Unicode is disabled
- check for Py_USING_UNICODE in all places that use Unicode functions
- disables unicode literals, and the builtin functions
- add the types.StringTypes list
- remove Unicode literals from most tests.
types -- currently Type, List, None and NotImplemented. To be called
from Py_Initialize() instead of accumulating calls there.
Also rename type(None) to NoneType and type(NotImplemented) to
NotImplementedType -- naming the type identical to the object was
confusing.
returns that. (This fix is also by MvL; checkin it in because I want
to make more changes here. I'm still not 100% satisfied -- see
comments attached to the patch.)
- Add an explicit call to PyType_Ready(&PyList_Type) to pythonrun.c
(just for the heck of it, really -- we should either explicitly
ready all types, or none).
And remove all the extern decls in the middle of .c files.
Apparently, it was excluded from the header file because it is
intended for internal use by the interpreter. It's still intended for
internal use and documented as such in the header file.
case of objects with equal types which support tp_compare. Give
type objects a tp_compare function.
Also add c<0 tests before a few PyErr_Occurred tests.
NEEDS DOC CHANGES
A few more AttributeErrors turned into TypeErrors, but in test_contains
this time.
The full story for instance objects is pretty much unexplainable, because
instance_contains() tries its own flavor of iteration-based containment
testing first, and PySequence_Contains doesn't get a chance at it unless
instance_contains() blows up. A consequence is that
some_complex_number in some_instance
dies with a TypeError unless some_instance.__class__ defines __iter__ but
does not define __getitem__.
the code necessary to accomplish this is simpler and faster if confined to
the object implementations, so we only do this there.
This causes no behaviorial changes beyond a (very slight) speedup.
object's type didn't define tp_print, there were still cases where the
full "print uses str() which falls back to repr()" semantics weren't
honored. This resulted in
>>> print None
<None object at 0x80bd674>
>>> print type(u'')
<type object at 0x80c0a80>
Fixed this by always using the appropriate PyObject_Repr() or
PyObject_Str() call, rather than trying to emulate what they would do.
Also simplified PyObject_Str() to always fall back on PyObject_Repr()
when tp_str is not defined (rather than making an extra check for
instances with a __str__ method). And got rid of the special case for
strings.
Fix a very old flaw in PyObject_Print(). Amazing! When an object
type defines tp_str but not tp_repr, 'print x' to a real file
object would not call the tp_str slot but rather print a default style
representation: <foo object at 0x....>. This even though 'print x' to
a file-like-object would correctly call the tp_str slot.
and the test for errors, so that an error in the default compare
doesn't go undetected. This fixes SF Bug #132933 (submitted by
effbot) -- list.sort doesn't detect comparision errors.
PyObject_Dump(): New function that is useful when debugging Python's C
runtime. In something like gdb it can be a pain to get some useful
information out of PyObject*'s. This function prints the str() of the
object to stderr, along with the object's refcount and hex address.
PyGC_Dump(): Similar to PyObject_Dump() but knows how to cast from the
garbage collector prefix back to the PyObject* structure.
[See Misc/gdbinit for some useful gdb hooks]
none_dealloc(): Rather than SEGV if we accidentally decref None out of
existance, we assign None's and NotImplemented's destructor slot to
this function, which just calls abort().
Barry, that comment belongs in the code, not in the checkin msg.
The code *used* to do this correctly (as you well know, since you
& I went thru considerable pain to fix this the first time).
However, because the *reason* for the convolution wasn't recorded
in the code as a comment, somebody threw it all away the first
time it got reworked.
c-code-isn't-often-self-explanatory-ly y'rs - tim
default_3way_compare(): Stick the checkin message from 2.110 in a
comment.
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.
Jeremy Hylton
Guido van Rossum
Tim Peters
Fred Drake
Neil Schemenauer
Barry Warsaw
Martin v. Löwis
Marc-André Lemburg