[Python-3000-checkins] r60376 - in python/branches/py3k: Lib/test/test_float.py Lib/test/test_long.py Objects/stringlib/formatter.h

[Nick Coghlan]

eric.smith wrote:
> Author: eric.smith
> Date: Sun Jan 27 22:07:59 2008
> New Revision: 60376
> 
> Modified:
>    python/branches/py3k/Lib/test/test_float.py
>    python/branches/py3k/Lib/test/test_long.py
>    python/branches/py3k/Objects/stringlib/formatter.h
> Log:
> Restrict format presentation types to those specified in the 'Standard Format Specifiers' section of PEP 3101.

I think this checkin goes too far in removing support for the floating 
point formatting codes from integers. Guido objected to %d working on 
floats last year, but expected %f and friends to continue to work on 
integers [1]. This makes sense when you consider that there is no data 
loss in displaying an integer as a floating point number, while there is 
a definite potential for data loss when going the other way.

Perhaps the PEP needs a tweak (referencing Guido's email) to state 
explicitly that the builtin integers understand the floating point 
formatting codes, but the builtin and standard library floating point 
types don't understand the integer codes? That area of the PEP is 
slightly problematic anyway where it suggests that integers could handle 
the floating point codes by delegating to float() - that isn't quite 
true, since the maximum precision on floats is less than the maximum 
precision on integers.

Cheers,
Nick.

[1]
http://mail.python.org/pipermail/python-3000/2007-August/009066.html


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Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
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