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

[Christian Heimes]

Terry Reedy wrote:
> If orig_data were mutable (the new buffer, as proposed in the PEP), would 
> not
> 
> for i in range(len(orig_data)):
>   orig_data[i] &= 0x1F
> 
> do it in place? (I don't have .0a1 to try on the current bytes.)

Good catch!

Python 3.0a1 (py3k:58282, Sep 29 2007, 15:07:57)
[GCC 4.1.2 (Ubuntu 4.1.2-0ubuntu4)] on linux2
>>> orig_data = b"abc"
>>> orig_data
b'abc'
>>> for i in range(len(orig_data)):
...   orig_data[i] &= 0x1F
...
>>> orig_data
b'\x01\x02\x03'

It'd be useful and more efficient if the new buffer type would support
the bit wise operations directly:

>>> orig_data &= 0x1F
TypeError: unsupported operand type(s) for &=: 'bytes' and 'int'
>>> orig_data &= b"\x1F"
TypeError: unsupported operand type(s) for &=: 'bytes' and 'bytes'

Christian