[Python-Dev] [Python-checkins] r64424 - in python/trunk:Include/object.h Lib/test/test_sys.py Misc/NEWSObjects/intobject.c Objects/longobject.c Objects/typeobject.cPython/bltinmodule.c

[Mark Dickinson]

On Fri, Jun 27, 2008 at 8:02 PM, Guido van Rossum <guido at python.org> wrote:
> Now that I've learned about the hex float format supported by C++ and
> Java, I wonder if it wouldn't be better to support conversion to and
> from that format and nothing else.

By the way, this particular format is also recommended by the draft versions
of IEEE 754r that I've seen:  section 7.12.2 of draft version 1.2.5
(this is publicly
available---there's a link from the wikipedia 754r page) says:

"""Implementations supporting binary formats shall provide conversions
between all supported internal binary
formats and external hexadecimal character sequences. External
hexadecimal character sequences for finite
numbers are of the form specified by C99 subclauses:
6.4.4.2 floating constants,
20.1.3 strtod,
7.19.6.2 fscanf (a, e, f, g), and
7.19.6.1 fprintf (a, A)."""

More recent 754r drafts spell the grammar out explicitly instead of
referring to C99,
and weaken the 'shall' (i.e., 'is required to') to a 'should' ('is
recommended to').

Mark