[Python-Dev] adding Construct to the standard library?

[Travis E. Oliphant]

Greg Ewing wrote:
> Travis Oliphant wrote:
> 
>> For what it's worth,  NumPy also defines a data-type object which it 
>> uses to describe the fundamental data-type of an array.  In the context 
>> of this thread it is also yet another way to describe a binary-packed 
>> structure in Python.
> 
> Maybe there should be a separate module providing
> a data-packing facility that ctypes, NumPy, etc.
> can all use (perhaps with their own domain-specific
> extensions to it).
> 
> It does seem rather silly to have about 3 or 4
> different incompatible ways to do almost exactly
> the same thing (struct, ctypes, NumPy and now
> Construct).

I agree.  Especially with ctypes and struct now in the standard library. 
  The problem, however, is that every module does something a little-bit 
different with the object.   NumPy needs a built-in object with at least 
a few fields defined.

The idea of "specifying the data-type" is different then it's 
representation to NumPy.

After looking at it, I'm not particularly fond of Construct's way to 
specify data-types, but then again we've been developing the array 
interface for just this purpose and so have some biased opinions.

Some kind of data-type specification would indeed be useful.  NumPy 
needs a built-in (i.e. written in C) data-type object internally.  If 
that builtin object were suitable generally then all the better.

For details, look at http://numeric.scipy.org/array_interface  (in 
particular the __array_descr__ field of the interface for what we came 
up with last year over several months of discussion.


-Travis