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

[Travis Oliphant]

Paul Moore wrote:
> 
> 
> Enough of the abstract. As a concrete example, suppose I have a (byte)
> string in my program containing some binary data - an ID3 header, or a
> TCP packet, or whatever. It doesn't really matter. Does your proposal
> offer anything to me in how I might manipulate that data (assuming I'm
> not using NumPy)? (I'm not insisting that it should, I'm just trying
> to understand the scope of the PEP).
> 

What do you mean by "manipulate the data."  The proposal for a 
data-format object would help you describe that data in a standard way 
and therefore share that data between several library that would be able 
to understand the data (because they all use and/or understand the 
default Python way to handle data-formats).

It would be up to the other packages to "manipulate" the data.

So, what you would be able to do is take your byte-string and create a 
buffer object which you could then share with other packages:

Example:

b = buffer(bytestr, format=data_format_object)

Now.

a = numpy.frombuffer(b)
a['field1']  # prints data stored in the field named "field1"

etc.

Or.

cobj = ctypes.frombuffer(b)

# Now, cobj is a ctypes object that is basically a "structure" that can 
be passed # directly to your C-code.

Does this help?

-Travis