460 lines
18 KiB
Plaintext
460 lines
18 KiB
Plaintext
Project: core implementation
|
|
****************************
|
|
|
|
Tasks:
|
|
|
|
Do binary operators properly. nb_add should try to call self.__add__
|
|
and other.__radd__. I think I'll exclude base types that define any
|
|
binary operator without setting the CHECKTYPES flag. *** This is
|
|
done, AFAICT. Even supports __truediv__ and __floordiv__. ***
|
|
|
|
Fix comparisons. There's some nasty stuff here: when two types are
|
|
not the same, and they're not instances, the fallback code doesn't
|
|
account for the possibility that they might be subtypes of a common
|
|
base type that defines a comparison.
|
|
|
|
Fix subtype_dealloc(). This currently searches through the list of
|
|
base types until it finds a type whose tp_dealloc is not
|
|
subtype_dealloc. I think this is not safe. I think the alloc/dealloc
|
|
policy needs to be rethought. *** There's an idea here that I haven't
|
|
worked out yet: just as object creation now has separate API's tp_new,
|
|
tp_alloc, and tp_init, destruction has tp_dealloc and tp_free. (Maybe
|
|
tp_fini should be added to correspond to tp_init?) Something
|
|
could/should be done with this. ***
|
|
|
|
Clean up isinstance(), issubclass() and their C equivalents. There
|
|
are a bunch of different APIs here and not all of them do the right
|
|
thing yet. There should be fewer APIs and their implementation should
|
|
be simpler. The old "abstract subclass" test should probably
|
|
disappear (if we want to root out ExtensionClass). *** I think I've
|
|
done 90% of this by creating PyType_IsSubtype() and using it
|
|
appropriately. For now, the old "abstract subclass" test is still
|
|
there, and there may be some places where PyObject_IsSubclass() is
|
|
called where PyType_IsSubtype() would be more appropriate. ***
|
|
|
|
Check for conflicts between base classes. I fear that the rules used
|
|
to decide whether multiple bases have conflicting instance variables
|
|
aren't strict enough. I think that sometimes two different classes
|
|
adding __dict__ may be incompatible after all.
|
|
|
|
Check for order conflicts. Suppose there are two base classes X and
|
|
Y. Suppose class B derives from X and Y, and class C from Y and X (in
|
|
that order). Now suppose class D derives from B and C. In which
|
|
order should the base classes X and Y be searched? This is an order
|
|
conflict, and should be disallowed; currently the test for this is not
|
|
implemented.
|
|
|
|
Clean up the GC interface. Currently, tp_basicsize includes the GC
|
|
head size iff tp_flags includes the GC flag bit. This makes object
|
|
size math a pain (e.g. to see if two object types have the same
|
|
instance size, you can't just compare the tp_basicsize fields -- you
|
|
have to conditionally subtract the GC head size). Neil has a patch
|
|
that improves the API in this area, but it's backwards incompatible.
|
|
(http://sf.net/tracker/?func=detail&aid=421893&group_id=5470&atid=305470)
|
|
I think I know of a way to fix the incompatibility (by switching to a
|
|
different flag bit). *** Tim proposed a better idea: macros to access
|
|
tp_basicsize while hiding the nastiness. This is done now, so I think
|
|
the rest of this task needn't be done. ***
|
|
|
|
Make the __dict__ of types declared with Python class statements
|
|
writable -- only statically declared types must have an immutable
|
|
dict, because they're shared between interpreter instances. Possibly
|
|
trap writes to the __dict__ to update the corresponding tp_<slot> if
|
|
an __<slot>__ name is affected. *** Done as part of the next task. ***
|
|
|
|
It should be an option (maybe a different metaclass, maybe a flag) to
|
|
*not* merge __dict__ with all the bases, but instead search the
|
|
__dict__ (or __introduced__?) of all bases in __mro__ order. (This is
|
|
needed anyway to unify classes completely.) *** Partly done.
|
|
Inheritance of slots from bases is still icky: (1) MRO is not always
|
|
respected when inheriting slots; (2) dynamic classes can't add slot
|
|
implementations in Python after creation (e.g., setting C.__hash__
|
|
doesn't set the tp_hash slot). ***
|
|
|
|
Universal base class (object). How can we make the object class
|
|
subclassable and define simple default methods for everything without
|
|
having these inherited by built-in types that don't want these
|
|
defaults? *** Done, really. ***
|
|
|
|
Add error checking to the MRO calculation. *** Done. ***
|
|
|
|
Make __new__ overridable through a Python class method (!). Make more
|
|
of the sub-algorithms of type construction available as methods. ***
|
|
After I implemented class methods, I found that in order to be able
|
|
to make an upcall to Base.__new__() and have it create an instance of
|
|
your class (rather than a Base instance), you can't use class methods
|
|
-- you must use static methods. So I've implemented those too. I've
|
|
hooked up __new__ in the right places, so the first part of this is
|
|
now done. I've also exported the MRO calculation and made it
|
|
overridable, as metamethod mro(). I believe that closes this topic
|
|
for now. I expect that some warts will only be really debugged when
|
|
we try to use this for some, eh, interesting types such as tuples. ***
|
|
|
|
There was a sequel to the __new__ story (see checkins). There
|
|
still is a problem: object.__new__ now no longer exists, because
|
|
it was inherited by certain extension types that could break. But
|
|
now when I write
|
|
|
|
class C(object):
|
|
def __new__(cls, *args):
|
|
"How do I call the default __new__ implementation???"
|
|
|
|
More -- I'm sure new issues will crop up as we go.
|
|
|
|
|
|
Project: loose ends and follow-through
|
|
**************************************
|
|
|
|
Tasks:
|
|
|
|
Make more (most?) built-in types act as their own factory functions.
|
|
|
|
Make more (most?) built-in types subtypable -- with or without
|
|
overridable allocation. *** This includes descriptors! It should be
|
|
possible to write descriptors in Python, so metaclasses can do clever
|
|
things with them. ***
|
|
|
|
Exceptions should be types. This changes the rules, since now almost
|
|
anything can be raised (as maybe it should). Or should we strive for
|
|
enforcement of the convention that all exceptions should be derived
|
|
from Exception? String exceptions will be another hassle, to be
|
|
deprecated and eventually ruled out.
|
|
|
|
Standardize a module containing names for all built-in types, and
|
|
standardize on names. E.g. should the official name of the string
|
|
type be 'str', 'string', or 'StringType'?
|
|
|
|
Create a hierarchy of types, so that e.g. int and long are both
|
|
subtypes of an abstract base type integer, which is itself a subtype
|
|
of number, etc. A lot of thinking can go into this!
|
|
|
|
*** NEW TASK??? ***
|
|
Implement "signature" objects. These are alluded to in PEP 252 but
|
|
not yet specified. Supposedly they provide an easily usable API to
|
|
find out about function/method arguments. Building these for Python
|
|
functions is simple. Building these for built-in functions will
|
|
require a change to the PyMethodDef structure, so that a type can
|
|
provide signature information for its C methods. (This would also
|
|
help in supporting keyword arguments for C methods with less work than
|
|
PyArg_ParseTupleAndKeywords() currently requires.) But should we do
|
|
this? It's additional work and not required for any of the other
|
|
parts.
|
|
|
|
|
|
Project: making classes use the new machinery
|
|
*********************************************
|
|
|
|
Tasks:
|
|
|
|
Try to get rid of all code in classobject.c by deferring to the new
|
|
mechanisms. How far can we get without breaking backwards
|
|
compatibility? This is underspecified because I haven't thought much
|
|
about it yet. Can we lose the use of PyInstance_Check() everywhere?
|
|
I would hope so!
|
|
|
|
|
|
Project: backwards compatibility
|
|
********************************
|
|
|
|
Tasks:
|
|
|
|
Make sure all code checks the proper tp_flags bit before accessing
|
|
type object fields.
|
|
|
|
Identify areas of incompatibility with Python 2.1. Design solutions.
|
|
Implement and test.
|
|
|
|
Some specific areas: a fair amount of code probably depends on
|
|
specific types having __members__ and/or __methods__ attributes.
|
|
These are currently not present (conformant to PEP 252, which proposes
|
|
to drop them) but we may have to add them back. This can be done in a
|
|
generic way with not too much effort. Tim adds: Perhaps that dir(object)
|
|
rarely returns anything but [] now is a consequence of this. I'm very
|
|
used to doing, e.g., dir([]) or dir("") in an interactive shell to jog my
|
|
memory; also one of the reasons test_generators failed.
|
|
|
|
Another area: going all the way with classes and instances means that
|
|
type(x) == types.InstanceType won't work any more to detect instances.
|
|
Should there be a mode where this still works? Maybe this should be
|
|
the default mode, with a warning, and an explicit way to get the new
|
|
way to work? (Instead of a __future__ statement, I'm thinking of a
|
|
module global __metaclass__ which would provide the default metaclass
|
|
for baseless class statements.)
|
|
|
|
|
|
Project: testing
|
|
****************
|
|
|
|
Tasks:
|
|
|
|
Identify new functionality that needs testing. Conceive unit tests
|
|
for all new functionality. Conceive stress tests for critical
|
|
features. Run the tests. Fix bugs. Repeat until satisfied.
|
|
|
|
Note: this may interact with the branch integration task.
|
|
|
|
|
|
Project: integration with main branch *** This is done - tim ***
|
|
*************************************
|
|
|
|
Tasks:
|
|
|
|
Merge changes in the HEAD branch into the descr-branch. Then merge
|
|
the descr-branch back into the HEAD branch.
|
|
|
|
The longer we wait, the more effort this will be -- the descr-branch
|
|
forked off quite a long time ago, and there are changes everywhere in
|
|
the HEAD branch (e.g. the dict object has been radically rewritten).
|
|
|
|
On the other hand, if we do this too early, we'll have to do it again
|
|
later.
|
|
|
|
Note from Tim: We should never again wait until literally 100s of files
|
|
are out of synch. I don't care how often I need to do this, provided only
|
|
that it's a tractable task each time. Once per week sounds like a good
|
|
idea. As is, even the trunk change to rangeobject.c created more than its
|
|
proper share of merge headaches, because it confused all the other reasons
|
|
include file merges were getting conflicts (the more changes there are, the
|
|
worse diff does; indeed, I came up with the ndiff algorithm in the 80s
|
|
precisely because the source-control diff program Cray used at the time
|
|
produced minimal but *senseless* diffs, thus creating artificial conflicts;
|
|
paying unbounded attention to context does a much better job of putting
|
|
changes where they make semantic sense too; but we're stuck with Unix diff
|
|
here, and it isn't robust in this sense; if we don't keep its job simple,
|
|
it will make my job hell).
|
|
|
|
Done:
|
|
To undo or rename before final merge: Modules/spam.c has worked its
|
|
way into the branch Unix and Windows builds (pythoncore.dsp and
|
|
PC/config.c); also imported by test_descr.py. How about renaming to
|
|
xxsubtype.c (whatever) now? *** this is done - tim ***
|
|
|
|
|
|
Project: performance tuning
|
|
***************************
|
|
|
|
Tasks:
|
|
|
|
Pick or create a general performance benchmark for Python. Benchmark
|
|
the new system vs. the old system. Profile the new system. Improve
|
|
hotspots. Repeat until satisfied.
|
|
|
|
Note: this may interact with the branch integration task.
|
|
|
|
|
|
Project: documentation
|
|
**********************
|
|
|
|
Tasks:
|
|
|
|
Update PEP 252 (descriptors). Describe more of the prototype
|
|
implementation
|
|
|
|
Update PEP 253 (subtyping). Complicated architectural wrangling with
|
|
metaclasses. There is an interaction between implementation and
|
|
description.
|
|
|
|
Write PEP 254 (unification of classes). This should discuss what
|
|
changes for ordinary classes, and how we can make it more b/w
|
|
compatible.
|
|
|
|
Other documentation. There needs to be user documentation,
|
|
eventually.
|
|
|
|
|
|
Project: community interaction
|
|
******************************
|
|
|
|
Tasks:
|
|
|
|
Once the PEPs are written, solicit community feedback, and formulate
|
|
responses to the feedback. Give the community enough time to think
|
|
over this complicated proposal. Provide the community with a
|
|
prototype implementation to test. Try to do this *before* casting
|
|
everything in stone!
|
|
|
|
MERGE BEGIN ****************************************************************
|
|
Merge details (this section is Tim's scratchpad, but should help a lot if
|
|
he dies of frustration while wrestling with CVS <0.9 wink>).
|
|
----------------------------------------------------------------------------
|
|
2001-08-01 Merging descr-branch back into trunk.
|
|
|
|
Tagged trunk about 22:05:
|
|
cvs tag date2001-08-01 python
|
|
|
|
Merged trunk delta into branch:
|
|
cvs -q -z3 up -j date2001-07-30 -j date2001-08-01 descr
|
|
|
|
No conflicts (! first time ever!) ... but problems with pythoncore.dsp.
|
|
Resolved.
|
|
|
|
Rebuilt from scratch; ran all tests; checked into branch about 22:40.
|
|
|
|
Merged descr-branch back into trunk (SEE BELOW -- this specific way of
|
|
doing it was a bad idea):
|
|
|
|
cvs -q -z3 up -j descr-branch python
|
|
|
|
34 conflicts. Hmm! OK, looks like every file in the project with an
|
|
embedded RCS Id is "a conflict". Others make no sense, e.g., a dozen
|
|
conflicts in dictobject.c, sometimes enclosing identical(!) blobs of
|
|
source code. And CVS remains utterly baffled by Python type object decls.
|
|
Every line of ceval.c's generator code is in conflict blocks ... OK,
|
|
there's no pattern or sense here, I'll just deal with it.
|
|
|
|
Conflicts resolved; rebuilt from scratch; test_weakref fails. Didn't find
|
|
an obvious reason and it was late, so committed it anyway. Tagged the
|
|
trunk then with tag:
|
|
|
|
after-descr-branch-merge
|
|
|
|
Tracked the test_weakref failure to a botched conflict resolution in
|
|
classobject.c; checked in a fix.
|
|
|
|
LATER: The merge should have been done via:
|
|
|
|
upd -j date2001-08-01 -j descr-branch python
|
|
|
|
instead. This would have caused only one conflict, a baffler in
|
|
bltinmodule.c. It would have avoided the classobject.c error I made.
|
|
Luckily, except for that one, we got to the same place in the end anyway,
|
|
apart from a few curious tabs-vs-spaces differences.
|
|
----------------------------------------------------------------------------
|
|
2001-07-30
|
|
|
|
Doing this again while the expat and Windows installer changes are still
|
|
fresh on my mind.
|
|
|
|
Tagged trunk about 23:50 EDT on the 29th:
|
|
cvs tag date2001-07-30 python
|
|
|
|
Merged trunk delta into branch:
|
|
|
|
cvs -q -z3 up -j date2001-07-28 -j date2001-07-30 descr
|
|
|
|
2 conflicts, resolved.
|
|
----------------------------------------------------------------------------
|
|
2001-07-28
|
|
|
|
Tagged trunk about 00:31 EDT:
|
|
cvs tag date2001-07-28 python
|
|
|
|
Merged trunk delta into branch:
|
|
cvs -q -z3 up -j date2001-07-21 -j date2001-07-28 descr
|
|
|
|
4 conflicts, all RCS Ids. Resolved.
|
|
----------------------------------------------------------------------------
|
|
2001-07-21
|
|
|
|
Tagged trunk about 01:00 EDT:
|
|
cvs tag date2001-07-21 python
|
|
|
|
Merged trunk delta into branch:
|
|
cvs -q -z3 up -j date2001-07-17b -j date2001-07-21 descr
|
|
|
|
4 conflicts, mostly RCS Id thingies. Resolved.
|
|
|
|
Legit failure in new test_repr, because repr.py dispatches on the exact
|
|
string returned by type(x). type(1L) and type('s') differ in descr-branch
|
|
now, and repr.py didn't realize that, falling back to the "unknown type"
|
|
case for longs and strings. Repaired descr-branch repr.py.
|
|
----------------------------------------------------------------------------
|
|
2001-07-19
|
|
|
|
Removed the r22a1-branch tag (see next entry). Turns out Guido did add a
|
|
r22a1 tag, so the r22a1-branch tag served no point anymore.
|
|
----------------------------------------------------------------------------
|
|
2001-07-18 2.2a1 releaase
|
|
|
|
Immediately after the merge just below, I tagged descr-branch via
|
|
|
|
cvs tag r22a1-branch descr
|
|
|
|
Guido may or may not want to add another tag here (? maybe he wants to do
|
|
some more Unix fiddling first).
|
|
----------------------------------------------------------------------------
|
|
2001-07-17 building 2.2a1 release, from descr-branch
|
|
|
|
Tagged trunk about 22:00 EDT, like so:
|
|
cvs tag date2001-07-17b python
|
|
|
|
Merged trunk delta into branch via:
|
|
cvs -q -z3 up -j date2001-07-17a -j date2001-07-17b descr
|
|
----------------------------------------------------------------------------
|
|
2001-07-17
|
|
|
|
Tagged trunk about 00:05 EDT, like so:
|
|
cvs tag date2001-07-17a python
|
|
|
|
Merged trunk delta into branch via:
|
|
cvs -q -z3 up -j date2001-07-16 -j date2001-07-17a descr
|
|
----------------------------------------------------------------------------
|
|
2001-07-16
|
|
|
|
Tagged trunk about 15:20 EDT, like so:
|
|
cvs tag date2001-07-16 python
|
|
|
|
Guido then added all the other dist/ directories to descr-branch from that
|
|
trunk tag.
|
|
|
|
Tim then merged trunk delta into the branch via:
|
|
cvs -q -z3 up -j date2001-07-15 -j date2001-07-16 descr
|
|
----------------------------------------------------------------------------
|
|
2001-07-15
|
|
|
|
Tagged trunk about 15:44 EDT, like so:
|
|
cvs tag date2001-07-15 python
|
|
|
|
Merged trunk delta into branch via:
|
|
cvs -q -z3 up -j date2001-07-13 -j date2001-07-15 descr
|
|
|
|
Four files with conflicts, all artificial RCS Id & Revision thingies.
|
|
Resolved and committed.
|
|
----------------------------------------------------------------------------
|
|
2001-07-13
|
|
|
|
Tagged trunk about 22:13 EDT, like so:
|
|
cvs tag date2001-07-13 python
|
|
|
|
Merged trunk delta into branch via:
|
|
cvs -q -z3 up -j date2001-07-06 -j date2001-07-13 descr
|
|
|
|
Six(!) files with conflicts, mostly related to NeilS's generator gc patches.
|
|
Unsure why, but CVS seems always to think there are conflicts whenever a
|
|
line in a type object decl gets changed, and the conflict marking seems
|
|
maximally confused in these cases. Anyway, since I reviewed those patches
|
|
on the trunk, good thing I'm merging them, and darned glad it's still fresh
|
|
on my mind.
|
|
|
|
Resolved the conflicts, and committed the changes in a few hours total.
|
|
----------------------------------------------------------------------------
|
|
2001-07-07
|
|
|
|
Merge of trunk tag date2001-07-06 into descr-branch, via
|
|
cvs -q -z3 up -j date2001-07-06 mergedescr
|
|
was committed on 2001-07-07.
|
|
|
|
Merge issues:
|
|
|
|
(all resolved -- GvR)
|
|
----------------------------------------------------------------------------
|
|
2001-07-06
|
|
|
|
Tagged trunk a bit after midnight, like so:
|
|
|
|
C:\Code>cvs tag date2001-07-06 python
|
|
cvs server: Tagging python
|
|
cvs server: Tagging python/dist
|
|
cvs server: Tagging python/dist/src
|
|
T python/dist/src/.cvsignore
|
|
T python/dist/src/LICENSE
|
|
T python/dist/src/Makefile.pre.in
|
|
T python/dist/src/README
|
|
... [& about 3000 lines more] ...
|
|
|
|
This is the first trunk snapshot to be merged into the descr-branch.
|
|
Gave it a date instead of a goofy name because there's going to be more
|
|
than one of these, and at least it's obvious which of two ISO dates comes
|
|
earlier. These tags should go away after all merging is complete.
|
|
MERGE END ******************************************************************
|