Highlights:
 - Adding PyObject_Format.
 - Adding string.Format class.
 - Adding __format__ for str, unicode, int, long, float, datetime.
 - Adding builtin format.
 - Adding ''.format and u''.format.
 - str/unicode fixups for formatters.

The files in Objects/stringlib that implement PEP 3101 (stringdefs.h,
unicodedefs.h, formatter.h, string_format.h) are identical in trunk
and py3k.  Any changes from here on should be made to trunk, and
changes will propogate to py3k).

a subclass of it. Thanks John Lenton.

issues regarding user/group and permissions. Fixes 1050828.

Thanks to Christopher White from GHOP.

is still present in the containing structure.

function can be called recursively.
This was discussed in issue1020188.

In python codebase, all occurrences of Py_[X]DECREF(xxx->yyy) are suspect,
except when they appear in tp_new or tp_dealloc functions, or when
the member cannot be of a user-defined class.
Note that tp_init is not safe.

I do have a (crashing) example for every changed line.
Is it worth adding them to the test suite?

Example:

class SpecialStr(str):
    def __del__(self):
        s.close()

import cStringIO
s = cStringIO.StringIO(SpecialStr("text"))
s.close() # Segfault

Skip this test created by r60830.

They still remain fragile.

For example, a call to assertEqual currently does not make any allocation
(which surprised me at first).
But this can change when gc.collect also deletes the numerous "zombie frames"
attached to each function.

in the config dialog would cause non-Python files to be colored as if they
were Python source; improve use of ColorDelagator.  Patch 1334. Tal Einat.

Also correct a possible crash using ABCs.

This change is exactly the same as an optimisation
done 5 years ago, but on slot *access*:
http://svn.python.org/view?view=rev&rev=28297

  * place_summary_first copies the regrtest summary to the front of the file
    making it easier to scan quickly for problems.

  * count_failures gets the actual count of the number of failing tests, not
    just a 1 (some failures) or 0 (no failures).

In PyNumber_ToBase, changed from an assert to returning an error when PyObject_Index() returns something other than an int or long.  It should never be possible to trigger this, as PyObject_Index checks to make sure it returns an int or long.

Thanks to Thomas Herve for the fix.

Fixed repr() and str() of complex numbers. Complex suffered from the same problem as floats but I forgot to test and fix them.

Use a static and interned string for __subclasscheck__ and __instancecheck__ as suggested by Thomas Heller in #2115

Implemented Martin's suggestion to clear the free lists during the garbage collection of the highest generation.

when trying to remove a pid that in not in the activechildren list.

self._numerator and self._denominator. This speeds abs() up from 12.2us to
10.8us and trunc() from 2.07us to 1.11us. This doesn't change _add and friends
because they're more complicated.

  ./python.exe -m timeit -s 'from fractions import Fraction' 'Fraction(3)`
31.7 usec/loop -> 9.2 usec/loop

  ./python.exe -m timeit -s 'from fractions import Fraction' 'Fraction(3, 2)'`
27.7 usec/loop -> 9.32 usec/loop

  ./python.exe -m timeit -s 'from fractions import Fraction; f = Fraction(3, 2)' 'Fraction(f)'
31.9 usec/loop -> 14.3 usec/loop

works.

Thanks to Jeroen Ruigrok van der Werven for the fix.