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[Python-Dev] PEP 332 revival in coordination with pep 349? [ Was:Re: release plan for 2.5 ?]

Adam Olsen rhamph at gmail.com
Wed Feb 15 12:08:46 CET 2006 
On 2/15/06, Ron Adam <rrr at ronadam.com> wrote:
> Greg Ewing wrote:
> > Ron Adam wrote:
> >>     b = bytes(0L) ->  bytes([0,0,0,0])
> >
> > No, bytes(0L) --> TypeError because 0L doesn't implement
> > the iterator protocol or the buffer interface.
>
> It wouldn't need it if it was a direct C memory copy.
>
> > I suppose long integers might be enhanced to support the
> > buffer interface in 3.0, but that doesn't seem like a good
> > idea, because the bytes you got that way would depend on
> > the internal representation of long integers. In particular,
>
> Since some longs will be of different length, yes a bytes(0L) could give
> differing results on different platforms, but it will always give the
> same result on the platform it is run on. I actually think this is a
> plus and not a problem. If you are using Python to implement a byte
> interface you need to *know* it is different, not have it hidden.
>
>      bytesize = len(bytes(0L))  # find how long a long is

I believe you're confusing a C long with a Python long.  A Python long
is implemented as an array and has variable size.

In any case we already have the struct module:

>>> import struct
>>> struct.calcsize('l')
4

--
Adam Olsen, aka Rhamphoryncus
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