[Python-Dev] PEP 467: last round (?)

[Ethan Furman]

On 09/03/2016 05:08 AM, Martin Panter wrote:
> On 1 September 2016 at 19:36, Ethan Furman wrote:

>> Deprecation of current "zero-initialised sequence" behaviour without removal
>> ----------------------------------------------------------------------------
>>
>> Currently, the ``bytes`` and ``bytearray`` constructors accept an integer
>> argument and interpret it as meaning to create a zero-initialised sequence
>> of the given size::
>>
>>      >>> bytes(3)
>>      b'\x00\x00\x00'
>>      >>> bytearray(3)
>>      bytearray(b'\x00\x00\x00')
>>
>> This PEP proposes to deprecate that behaviour in Python 3.6, but to leave
>> it in place for at least as long as Python 2.7 is supported, possibly
>> indefinitely.
>
> Can you clarify what “deprecate” means? Just add a note in the
> documentation, [...]

This one.

>> Addition of "getbyte" method to retrieve a single byte
>> ------------------------------------------------------
>>
>> This PEP proposes that ``bytes`` and ``bytearray`` gain the method
>> ``getbyte``
>> which will always return ``bytes``::
>
> Should getbyte() handle negative indexes? E.g. getbyte(-1) returning
> the last byte.

Yes.

>> Open Questions
>> ==============
>>
>> Do we add ``iterbytes`` to ``memoryview``, or modify
>> ``memoryview.cast()`` to accept ``'s'`` as a single-byte interpretation?  Or
>> do we ignore memory for now and add it later?
>
> Apparently memoryview.cast('s') comes from Nick Coghlan:
> <https://marc.info/?i=CADiSq7e=8ieyeW-tXf5diMS_5NuAOS5udv-3g_w3LTWN9WboJw@mail.gmail.com>.
> However, since 3.5 (https://bugs.python.org/issue15944) you can call
> cast("c") on most memoryviews, which I think already does what you
> want:
>
>>>> tuple(memoryview(b"ABC").cast("c"))
> (b'A', b'B', b'C')

Nice!

--
~Ethan~