[Python-3000] Immutable bytes -- looking for volunteer

[Talin]

Guido van Rossum wrote:
> This may have passed in a thread where no-one was listening, so I'm
> repeating it here.
> 
> I'm considering the following option: bytes would always be immutable,
> and for the few places (mostly in io.py) where a mutable bytes buffer
> would be handy, we use the array module. Then it would also make sense
> to make b[0] return a bytes array of length 1 instead of a small int
> -- bytes would be more similar to str in 2.x, albeit completely
> incompatible with str in terms of mixed operations.
> 
> It would help if someone explored creating a patch to implement this,
> just to see the minimum amount of code that would need to change
> compared to 3.0a1. (The challenge includes making all the tests pass
> again.)

I don't know if I mentioned this before, since (a) I didn't want to be a 
distraction while you were busy trying to make mutable bytes work 
everywhere, and (b) I didn't want to sound completely insane. However - 
here is my vision of how things would look in an ideal world:

Data Type   AbstractSequence  Immutable   Mutable
=========   ================  =========   =======
byte        ByteSequence      bytes       buffer
character   CharSequence      str         strbuf

'buffer' could be an array.array, although if it's used frequently 
enough an optimized special-case 'buffer' class might be better. And it 
can have methods that array doesn't have.

-- Talin