On 2/15/06, Neil Schemenauer <[EMAIL PROTECTED]> wrote:
> This could be a replacement for PEP 332. At least I hope it can
> serve to summarize the previous discussion and help focus on the
> currently undecided issues.
>
> I'm too tired to dig up the rules for assigning it a PEP number.
> Also, there are probably silly typos, etc. Sorry.
I may check it in for you, although right now it would be good if we
had some more feedback.
I noticed one behavior in your pseudo-code constructor that seems
questionable: while in the Q&A section you explain why the encoding is
ignored when the argument is a str instance, in fact you require an
encoding (and one that's not "ascii") if the str instance contains any
non-ASCII bytes. So bytes("\xff") would fail, but bytes("\xff",
"blah") would succeed. I think that's a bit strange -- if you ignore
the encoding, you should always ignore it. So IMO bytes("\xff") and
bytes("\xff", "ascii") should both return the same as bytes([255]).
Also, there's a code path where the initializer is a unicode instance
and its encode() method is called with None as the argument. I think
both could be fixed by setting the encoding to
sys.getdefaultencoding() if it is None and the argument is a unicode
instance:
def bytes(initialiser=[], encoding=None):
if isinstance(initialiser, basestring):
if isinstance(initialiser, unicode):
if encoding is None:
encoding = sys.getdefaultencoding()
initialiser = initialiser.encode(encoding)
initialiser = [ord(c) for c in initialiser]
elif encoding is not None:
raise TypeError("explicit encoding invalid for non-string "
"initialiser")
create bytes object and fill with integers from initialiser
return bytes object
BTW, for folks who want to experiment, it's quite simple to create a
working bytes implementation by inheriting from array.array. Here's a
quick draft (which only takes str instance arguments):
from array import array
class bytes(array):
def __new__(cls, data=None):
b = array.__new__(cls, "B")
if data is not None:
b.fromstring(data)
return b
def __str__(self):
return self.tostring()
def __repr__(self):
return "bytes(%s)" % repr(list(self))
def __add__(self, other):
if isinstance(other, array):
return bytes(super(bytes, self).__add__(other))
return NotImplemented
--
--Guido van Rossum (home page: http://www.python.org/~guido/)
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