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

[Paul Moore]

On 10/31/06, Travis Oliphant <oliphant.travis at ieee.org> wrote:
> Martin v. Löwis wrote:
> > [...] because I still don't quite understand what the PEP
> > wants to achieve.
> >
>
> Are you saying you still don't understand after having read the extended
> buffer protocol PEP, yet?

I can't speak for Martin, but I don't understand how I, as a Python
programmer, might use the data type objects specified in the PEP. I
have skimmed the extended buffer protocol PEP, but I'm conscious that
no objects I currently use support the extended buffer protocol (and
the PEP doesn't mention adding support to existing objects), so I
don't see that as too relevant to me.

I have also installed numpy, and looked at the help for numpy.dtype,
but that doesn't add much to the PEP. The freely available chapters of
the numpy book explain how dtypes describe data structures, but not
how to use them. The freely available Numeric documentation doesn't
refer to dtypes, as far as I can tell. Is there any documentation on
how to use dtypes, independently of other features of numpy? If not,
can you clarify where the benefit lies for a Python user of this
proposal? (I understand the benefits of a common language for
extensions to communicate datatype information, but why expose it to
Python? How do Python users use it?)

This is probably all self-evident to the numpy community, but I think
that as the PEP is aimed at a wider audience it needs a little more
background.

Paul.