Optimization of str.format() for cases with str, unicode, int, long,
and float arguments. This gives about 30% speed improvement for the
simplest (but most common) cases. This patch skips the __format__
dispatch, and also avoids creating an object to hold the format_spec.
Unfortunately there's a complication in 2.6 with int, long, and float
because they always expect str format_specs. So in the unicode
version of this optimization, just check for unicode objects. int,
float, long, and str can be added later, if needed.
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).