[Python-Dev] PEP: Adding data-type objects to Python

[Travis Oliphant]

Martin v. Löwis wrote:
> Stephan Tolksdorf schrieb:
> 
>>While Travis' proposal encompasses the data format functionality within 
>>the struct module and overlaps with what ctypes has to offer, it does 
>>not aim to replace ctypes.
> 
> 
> This discussion could have been a lot shorter if he had said so.
> Unfortunately (?) he stated that it was *precisely* a motivation
> of the PEP to provide a standard data description machinery that
> can then be adopted by the struct, array, and ctypes modules.

Struct and array I was sure about.  Ctypes less sure.  I'm very sorry 
for the distraction I caused by mis-stating my objective.   My objective 
is really the extended buffer protocol.  The data-type object is a means 
to that end.

I do think ctypes could make use of the data-type object and that there 
is a real difference between using Python type objects as data-format 
descriptions and using another Python type for those descriptions.  I 
thought to go the ctypes route (before I even knew what ctypes did) but 
decided against it for a number of reasons.

But, nonetheless those are side issues.  The purpose of the PEP is to 
provide an object that the extended buffer protocol can use to share 
data-format information.  It should be considered primarily in that context.

-Travis