I think this would be useful and I'll try it out in features/pep-3118#memoryview.

Syntax options that I'd prefer:

a = array.array('i', [1,2,3])
m = memoryview(a, 'B')


Or go all the way and make memoryview take any flag:

a = array.array('i', [1,2,3])
m = memoryview(a, getbuf=PyBUF_SIMPLE)


This is what I currently do in _testbuffer.c:


>>> from _testbuffer import *
>>> import array
>>> a = array.array('i', [1,2,3])
>>> nd = ndarray(a, getbuf=PyBUF_SIMPLE)
>>> nd.format
''
>>> nd.len
12
>>> nd.shape
()
>>> nd.strides
()
>>> nd.itemsize # XXX array_getbuf should set this to 1.
4



We would need to fix various getbuffer() methods to adhere to
strict rules that I've posed here:

http://mail.scipy.org/pipermail/numpy-discussion/2011-August/058189.html