For more comments, read the patches@python.org archives.
For documentation read the comments in mymalloc.h and objimpl.h.
(This is not exactly what Vladimir posted to the patches list; I've
made a few changes, and Vladimir sent me a fix in private email for a
problem that only occurs in debug mode. I'm also holding back on his
change to main.c, which seems unnecessary to me.)
The previous checkin (2.84) added a PyErr_Format call that made the
cost of raising an AttributeError much more expensive. In general
this doesn't matter, except that checks for __init__ and
__del__ methods, where exceptions are caught and cleared in C, also
got much more expensive.
The fix is to split instance_getattr1 into two calls:
instance_getattr2 checks the instance and the class for the attribute
and returns it or returns NULL on error. It does not raise an
exception.
instance_getattr1 does rexec checks, then calls instance_getattr2. It
raises an exception if instance_getattr2 returns NULL.
PyInstance_New and instance_dealloc now call instance_getattr2
directly.
In line with a similar checkin to object.c a while ago, this patch
gives a more descriptive error message for an attribute error on a
class instance. The message now looks like:
AttributeError: 'Descriptor' instance has no attribute 'GetReturnType'
not in restricted mode.
__dict__ can be set to any dictionary; the cl_getattr, cl_setattr and
cl_delattr slots are refreshed.
__name__ can be set to any string.
__bases__ can be set to to a tuple of classes, provided they are not
subclasses of the class whose attribute is being assigned.
__getattr__, __setattr__ and __delattr__ can be set to anything, or
deleted; the appropriate slot (cl_getattr, cl_setattr, cl_delattr) is
refreshed.
(Note: __name__ really doesn't need to be a special attribute, but
that would be more work.)
former lets you give an instance a set of new instance vars. The
latter lets you give it a new class. Both are typechecked and
disallowed in restricted mode.
For classes, the check for read-only special attributes is tightened
so that only assignments to __dict__, __bases__, __name__,
__getattr__, __setattr__, and __delattr__ (these could be made to work
as well, but I don't know if that's useful -- let's see first whether
mucking with instances will help).
Removed im_doc attribute; __name__ and __doc__ are now handled by
special casing in instancemethodgetattr(). This saves a few bytes and
INCREF/DECREF calls per i.m. object allocation/deallocation.
entirely redone operator overloading. The rules for class
instances are now much more relaxed than for other built-in types
(whose coerce must still return two objects of the same type)
* Objects/floatobject.c: add overflow check when converting float
to int and implement truncation towards zero using ceil/float
* Objects/longobject.c: change ValueError to OverflowError when
converting to int
* Objects/rangeobject.c: modernized
* Objects/stringobject.c: use HAVE_LIMITS instead of __STDC__
* Objects/xxobject.c: changed to use new style (not finished?)
and __setattr__ support to override getattr(x, name) and
setattr(x, name, value) for class instances. This uses a special
hack whereby the class is supposed to be static: the __getattr__
and __setattr__ methods are looked up only once and saved in the
instance structure for speed
* posixmodule.c: don't prototype getcwd() -- it's not portable...
* mappingobject.c: double-check validity of last_name_char in
dict{lookup,insert,remove}.
* arraymodule.c: need memmove only for non-STDC Suns.
* Makefile: comment out HTML_LIBS and XT_USE by default
* pythonmain.c: don't prototype getopt() -- it's not standardized
* socketmodule.c: cast flags arg to {get,set}sockopt() and addrbuf arg to
recvfrom() to (ANY*).
* pythonrun.c (initsigs): fix prototype, make it static
* intobject.c (LONG_BIT): only #define it if not already defined
* classobject.[ch]: remove all references to unused instance_convert()
* mappingobject.c (getmappingsize): Don't return NULL in int function.
without .py file); Bill's dynamic loading for SunOS using shared
libraries.
pwdmodule.c (mkgrent): remove DECREF of uninitialized variable.
classobject.c (instance_getattr): Fix case when class lookup returns
unbound method instead of function.
function found as instance data.
* socketmodule.c: added 'flags' argument sendto/recvfrom, rewrite
argument parsing in send/recv.
* More changes related to access (terminology change: owner instead of
class; allow any object as owner; local/global variables are owned
by their dictionary, only class/instance data is owned by the class;
"from...import *" now only imports objects with public access; etc.)
* Added "access *: ...", made access work for class methods.
* Introduced subclass check: make sure that when calling
ClassName.methodname(instance, ...), the instance is an instance of
ClassName or of a subclass thereof (this might break some old code!)
yet). The class is now passed to eval_code and stored in the current
frame. It is also stored in instance method objects. An "unbound"
instance method is now returned when a function is retrieved through
"classname.funcname", which when called passes the class to eval_code.
(1) dictionaries/mappings now have attributes values() and items() as
well as keys(); at the C level, use the new function mappinggetnext()
to iterate over a dictionary.
(2) "class C(): ..." is now illegal; you must write "class C: ...".
(3) Class objects now know their own name (finally!); and minor
improvements to the way how classes, functions and methods are
represented as strings.
(4) Added an "access" statement and semantics. (This is still
experimental -- as long as you don't use the keyword 'access' nothing
should be changed.)
* Stubs for faster implementation of local variables (not yet finished)
* Added function name to code object. Print it for code and function
objects. THIS MAKES THE .PYC FILE FORMAT INCOMPATIBLE (the version
number has changed accordingly)
* Print address of self for built-in methods
* New internal functions getattro and setattro (getattr/setattr with
string object arg)
* Replaced "dictobject" with more powerful "mappingobject"
* New per-type functio tp_hash to implement arbitrary object hashing,
and hashobject() to interface to it
* Added built-in functions hash(v) and hasattr(v, 'name')
* classobject: made some functions static that accidentally weren't;
added __hash__ special instance method to implement hash()
* Added proper comparison for built-in methods and functions
* Fixcprt.py: added [-y file] option, do only files younger than file.
* modsupport.[ch]: added vmkvalue().
* intobject.c: use mkvalue().
* stringobject.c: added "formatstring"; renamed string* to string_*;
ceval.c: call formatstring for string % value.
* longobject.c: close memory leak in divmod.
* parsetok.c: set result node to NULL when returning an error.
* flmodule.c: added some missing functions; changed readonly flags of
some data members based upon FORMS documentation.
* listobject.c: fixed int/long arg lint bug (bites PC compilers).
* several: removed redundant print methods (repr is good enough).
* posixmodule.c: added (still experimental) process group functions.
coercion is now completely generic.
* ceval.c: for instances, don't coerce for + and *; * reverses
arguments if left one is non-instance numeric and right one sequence.
Jeremy Hylton
Guido van Rossum
Sjoerd Mullender