Home Original page

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

Victor Stinner victor.stinner at gmail.com
Thu Sep 1 17:06:15 EDT 2016 
2016-09-01 21:36 GMT+02:00 Ethan Furman <ethan at stoneleaf.us>:
> Abstract
> ========
>
> This PEP proposes five small adjustments to the APIs of the ``bytes`` and
> ``bytearray`` types to make it easier to operate entirely in the binary
> domain:

You should add bchr() in the Abstract.


> * Deprecate passing single integer values to ``bytes`` and ``bytearray``
> * Add ``bytes.fromsize`` and ``bytearray.fromsize`` alternative constructors

I understand that main reason for this change is to catch bugs when
bytes(obj) is used and obj is not supposed to be an integer.

So I expect that bytes(int) will be quickly deprecated, but the PEP
doesn't schedule a removal of the feature. So it looks more than only
adding an alias to bytes(int).

I would prefer to either schedule a removal of bytes(int), or remove
bytes.fromsize() from the PEP.


> * Add ``bytes.fromord`` and ``bytearray.fromord`` alternative constructors

Hum, you already propose to add a builtin function. Why would we need
two ways to create a single byte?

I'm talking about bchr(int)==bytes.fromord(int). I'm not sure that
there is an use case for bytearray.fromord(int).


> * Add ``bytes.getbyte`` and ``bytearray.getbyte`` byte retrieval methods
> * Add ``bytes.iterbytes`` and ``bytearray.iterbytes`` alternative iterators

I like these ones :-)



> In particular, there's a reasonable case to be made
> that ``bytes(x)`` (where ``x`` is an integer) should behave like the
> ``bytes.fromint(x)`` proposal in this PEP.

"fromint"? Is it bytes.fromord()/bchr()?


> 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?

It's nice to have bytes.iterbytes() to help porting Python 2 code, but
I'm not sure that this function would be super popular in new Python 3
code.

I don't think that a memoryview.iterbytes() (or cast("s")) would be useful.

Victor
More information about the Python-Dev mailing list