Greg Ewing wrote:
> tomer filiba wrote:
>
>> yes, but +=/-= can be overriden to provide "efficient seeking". and, just
>> thought about it: just like negative indexes of sequences, negative positions
>> should be relative to the end of the stream. for example:
>>
>> f.position = 4 # absolute -- seek(4, "start")
>> f.position += 6 # relative to current -- seek(6, "curr")
>> f.position = -7 # relative to end of stream -- seek(-7, "end")
>
> How would you seek to exactly the end of the file,
> without introducing signed integer zeroes to Python?-)
Since it doesn't mean anything else, you could define a position of "None" as
meaning 'just past the last valid byte in the file' (i.e., right at the end).
Then "f.position = None" would seek to the end. This actually matches the way
None behaves when it is used as the endpoint of a slice: range(3)[0:None]
returns [0, 1, 2, 3].
If that's not intuitive enough for your tastes, then a class attribute would
also work:
f.position = f.END
(f.END would be serving as 'signed zero', since f.position -=1 and f.position
= -1 would do the same thing)
FWIW, I also realised my objection to properties raising IOError doesn't apply
for IO streams - unlike path objects, an IO stream *only* makes sense if you
have access to the underlying IO layer. So documenting certain properties as
potentially raising IOError seems legitimate in this case.
I'm glad I thought of that, since I like this API a lot better than mucking
around with passing strings to seek() ;)
Cheers,
Nick.
--
Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia
---------------------------------------------------------------
http://www.boredomandlaziness.org
_______________________________________________
Python-3000 mailing list
[email protected]
http://mail.python.org/mailman/listinfo/python-3000
Unsubscribe:
http://mail.python.org/mailman/options/python-3000/archive%40mail-archive.com
