Highlights: import and friends will understand any of \r, \n and \r\n
as end of line. Python file input will do the same if you use mode 'U'.
Everything can be disabled by configuring with --without-universal-newlines.
See PEP278 for details.
This introduces:
- A new operator // that means floor division (the kind of division
where 1/2 is 0).
- The "future division" statement ("from __future__ import division)
which changes the meaning of the / operator to implement "true
division" (where 1/2 is 0.5).
- New overloadable operators __truediv__ and __floordiv__.
- New slots in the PyNumberMethods struct for true and floor division,
new abstract APIs for them, new opcodes, and so on.
I emphasize that without the future division statement, the semantics
of / will remain unchanged until Python 3.0.
Not yet implemented are warnings (default off) when / is used with int
or long arguments.
This has been on display since 7/31 as SF patch #443474.
Flames to /dev/null.
This is really stupid because it cannot be suppressed or altered using
the warning framework; that's because the warning framework is built
on Python interpreter internals, and the parser generator doesn't have
access to any of those (you cannot use anything of type PyObject * in
the parser).
But it's better than nothing, and implementing a proper check for this
appears to require modifying compile.c in a dozen places, for which I
don't have the stamina today. I promise we'll do better in 2.2a2.
At least it tells you the filename and line number (unlike the first
hack I considered :-).
that 'yield' is a keyword. This doesn't help test_generators at all! I
don't know why not. These things do work now (and didn't before this
patch):
1. "from __future__ import generators" now works in a native shell.
2. Similarly "python -i xxx.py" now has generators enabled in the
shell if xxx.py had them enabled.
3. This program (which was my doctest proxy) works fine:
from __future__ import generators
source = """\
def f():
yield 1
"""
exec compile(source, "", "single") in globals()
print type(f())
the yield statement. I figure we have to have this in before I can
release 2.2a1 on Wednesday.
Note: test_generators is currently broken, I'm counting on Tim to fix
this.
