[Python-Dev] Fwd: I was just thinking that os.path could use some love... (original) (raw)

Guido van Rossum guido at python.org
Wed Jan 30 22:26:08 CET 2013

Thoughts on os.path? What happened to the idea of a new path object?

--Guido

---------- Forwarded message ---------- From: Talin <viridia at gmail.com> Date: Wed, Jan 30, 2013 at 12:34 PM Subject: Re: I was just thinking that os.path could use some love... To: Guido van Rossum <guido at python.org>

On Wed, Jan 30, 2013 at 11:33 AM, Guido van Rossum <guido at python.org> wrote:

Hmm... Mind if I just forward to python-dev? IIRC there's been some discussion about a newfangled path object, but I lost track of where the discussion went. (Or you can post there yourself. :-)

Sure - forward away. Is this the same as the path object idea that was floated 5 years ago? I've yet to see any set of convenience methods for paths that are so compelling as to be worth all of the time and energy needed to update all of the various APIs which now expect paths to be passed in as strings.

On Wed, Jan 30, 2013 at 11:13 AM, Talin <viridia at gmail.com> wrote: > I just realized that os.path hasn't changed in a long time. Here's a couple > of ideas for additions: > > os.path.splitall(path) - splits all path components into a tuple - so for > example, 'this/is/a/path' turns into ('this', 'is', 'a', 'path'). If there's > a trailing slash, the last item in the tuple will be a zero-length string. > The main reason for having this in os.path is so that we can remain > separator-character-agnostic. Would it also return a leading empty string if the path starts with /? What about Windows C: or //host/ prefixes??? I would say that it should only split on directory separators, not any other kind of delimiter, so that each component is a valid filesystem identifier. Further, the operation should be reversible by calling os.path.join(*dirnames). So it's a little more complex than just string.split('/').

Part of the reason for wanting the splitall function is to implement the common prefix function - you take all the paths, bust them into tuples, look for the longest tuple prefix, and then join the result back into a path. This means that os.path.join(*os.path.splitall(path)) must reproduce the original path exactly.

> An alternative would be to add an optional 'maxsplits' parameter to > os.path.split. Default would be 1; 0 = unlimited. Main disadvantage would be > that no one would ever use values 2, 3, etc... but it would be more > compatible with other split apis. > > A version of os.path.commonprefix that always produces valid paths (and > works by path component, not character-by-character). > > I can probably think of others if I look at some other path manipulation > apis. llvm::sys::path has a bunch if I recall... > > -- > -- Talin

-- --Guido van Rossum (python.org/~guido)

-- -- Talin

-- --Guido van Rossum (python.org/~guido)

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