Peng Yu wrote:
On Tue, Nov 17, 2009 at 9:18 PM, alex23 <wuwe...@gmail.com> wrote:
Peng Yu <pengyu...@gmail.com> wrote:
But the document doesn't say shutil need to be imported in order to
use WindowsError. Shall the document or the code be corrected?
Neither, it's your understanding that needs correction.
Benjamin wasn't trying to say that WindowsError is defined within
shutil, he was showing that it _isn't_ defined within shutil on a non-
Windows machine.
As you're looking in shutil.py, you should have noticed this at the
very top, just beneath the declaration of the Error exception:
try:
WindowsError
except NameError:
WindowsError =one
This looks for the existence of the WindowsError exception - present
only under Windows - and if it's not there it binds the name to None.
You'll notice that the only place it's used in shutil.py is prefixed
by the test WindowsError is not None...
I think the mention of the exception being raised when a "Windows-
specific error occurs" should make it pretty clear that this is a
Windows-only exception.
I don't know about others. The wording "Windows-specific error occurs"
was ambiguous to me. It could refers to some errors resulted from
copying (on a linux machine) some files from linux file systems to
windows files systems (via samba, maybe). I recommend to revise the
document a little bit to avoid confusion.
Worse, even if the exception cannot be thrown on a non-Windows
environment, leaving it undefined makes it very awkward to write
portable code. An except clause that can never happen in a particular
environment is pretty innocent. Or somebody can use a base class for
his except clause, to catch this error and other related ones. But it
blows up if you explicitly use this exception. I think that needs
documentation, at a minimum.
DaveA
--
http://mail.python.org/mailman/listinfo/python-list
