On 05/10/2010 12:04, Steven D'Aprano wrote:
On Tue, 5 Oct 2010 07:21:15 pm Chris Withers wrote:
On 25/09/2010 04:25, Steven D'Aprano wrote:
1. Return the case of a filename in some canonical form which
depends on the file system?
2. Return the case of a filename as it is actually stored on disk?
How do 1 and 2 differ?
Case #1 imposes a particular canonical form, regardless of what is
actually stored on disk. It is similar to normpath, except that we
could have different canonical forms depending on what the file system
was. normpath merely generalises from the operating system, and never
looks at the file system.
Ah, okay, yeah, that's actually an anti-goal for me ;-)
Case #2 says to actually look at the file and see what the file system
considers it's name to be. Consider a NTFS file system. By default it
is case-preserving and case-insensitive, although that can be changed.
(Just because a file system is NTFS doesn't mean that will be
case-insensitive. NTFS can also run in a POSIX mode which is
case-sensitive. But I digress.)
Yeah, this is definitely where I think the missing use case lies...
FWIW, the use case that setuptools has (and
for which it currently incorrectly uses normpath) is number 2.
4. Return the case of a filename in some arbitrarily-chosen
canonical form which does not depend on the file system?
This is what normpath does, but only if you're on Windows ;-)
Not quite. macpath.normcase() also lowercases the path. So does the
module for OS/2.
Interesting, since I develop on MacOS, Linux and Windows and only
experienced the problem caused by setuptools normcase'ing distribution
names on Windows. The MacOS case also isn't in the docs.
In any case, Windows is not a file system. It is quite possible to have
virtually any combination of case-destroying, case-preserving,
-sensitive and -insensitive file systems on the one Windows system. Say,
a FAT12 floppy, an NTFS partition, and an ext2 USB stick. Windows
doesn't ship with native support for ext2, but that doesn't mean it
can't be installed with third party drivers.
yes, exactly!
normpath pays no attention to any of this, and just lowercases the path.
At least that's cheap, and consistent, even if it solves the wrong
problem :)
...and creates a few more along the way ;-)
Chris
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Simplistix - Content Management, Batch Processing & Python Consulting
- http://www.simplistix.co.uk
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