[issue4136] merge json library with latest simplejson 2.0.x

Updated patch from Bob Ippolito, for updating the Python trunk json package to
the latest simplejson.

[Martin v. Löwis]

The one thing that IMO needs to be decided before this can be accept is the
version compatibility: what Python versions must this code stay compatible with?
That decision then needs to be implemented.

Apart from this (and the additional minor comments below), the patch looks fine.

http://codereview.appspot.com/20095/diff/1/13
File Lib/json/decoder.py (right):

http://codereview.appspot.com/20095/diff/1/13#newcode21
Line 21: nan, inf = struct.unpack('dd', _BYTES)
I think this can be simplified as

  nan, inf = struct.unpack('>dd', _BYTES)

http://codereview.appspot.com/20095/diff/1/12
File Lib/json/encoder.py (right):

http://codereview.appspot.com/20095/diff/1/12#newcode31
Line 31: INFINITY = float('1e66666')
Why not decoder.PosInf?

http://codereview.appspot.com/20095/diff/1/14
File Modules/_json.c (right):

http://codereview.appspot.com/20095/diff/1/14#newcode3
Line 3: #if PY_VERSION_HEX < 0x02060000 && !defined(Py_TYPE)
Is Python before 2.6 even supported anymore? ISTM that the usage of .format on
strings outrules Python2.5 and earlier.

[bob.ippolito]

simplejson maintains Python 2.4+ compatibility, but json maintains 2.6+. I could
produce another patch that manually removes these few remaining nits if it's
necessary.

http://codereview.appspot.com/20095/diff/1/13
File Lib/json/decoder.py (right):

http://codereview.appspot.com/20095/diff/1/13#newcode21
Line 21: nan, inf = struct.unpack('dd', _BYTES)
On 2009/02/28 09:28:11, Martin v. Löwis wrote:
> I think this can be simplified as
> 
>   nan, inf = struct.unpack('>dd', _BYTES)

Not while maintaining Python 2.4 compatibility, you will get frexp() out of
range. I suppose that this could be another function that gets manually fixed up
for Python's json module (like the .format strings) but it really doesn't seem
that important. I have added a comment to this effect in r175 of simplejson

http://codereview.appspot.com/20095/diff/1/12
File Lib/json/encoder.py (right):

http://codereview.appspot.com/20095/diff/1/12#newcode31
Line 31: INFINITY = float('1e66666')
On 2009/02/28 09:28:11, Martin v. Löwis wrote:
> Why not decoder.PosInf?

Good point. This is fixed in r174 of simplejson.

http://codereview.appspot.com/20095/diff/1/14
File Modules/_json.c (right):

http://codereview.appspot.com/20095/diff/1/14#newcode3
Line 3: #if PY_VERSION_HEX < 0x02060000 && !defined(Py_TYPE)
Python >= 2.6 is the compatibility target, all of those defines could be removed
but they are necessary upstream in simplejson because it supports >= 2.4

On 2009/02/28 09:28:11, Martin v. Löwis wrote:
> Is Python before 2.6 even supported anymore? ISTM that the usage of .format on
> strings outrules Python2.5 and earlier.