[Python-3000] PEP 3137: Immutable Bytes and Mutable Buffer

[Guido van Rossum]

[PEP 3137]
> > **Open Issue:** I'm undecided on whether indexing bytes and buffer
> > objects should return small ints (like the bytes type in 3.0a1, and
> > like lists or array.array('B')), or bytes/buffer objects of length 1
> > (like the str type).  The latter (str-like) approach will ease porting
> > code from Python 2.x; but it makes it harder to extract values from a
> > bytes array.

On 9/26/07, Brett Cannon <brett at python.org> wrote:
> How much do you care about making the 2 -> 3 transition easy?  If you
> don't go the str way then comparisons like ``bytes_[0] == b"A"`` won't
> work unless you allow comparisons between ints and length 1
> bytes/buffers.  Extracting a single item is not horrendous if you pass
> it to int().
>
> Personally I say go with the list-like semantics.  Having the
> following code return false seems odd (but not ridiculous) to me::
>
>   stuff = bytes([0, 1])
>   stuff[1] = 42
>   stuff[1] == 42
>
> So unless int comparisons are allowed I am -0 on the str-like semantics.

int comparisons would stick out like a sore thumb, especially since
they can only be reasonably made to work on 1-byte strings.

I'm still undecided (despite Marcin's eloquent argument for ints as
bytes) but I'm open for votes for this case.

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)