[Python-ideas] Working with Path objects: p-strings?

[Michel Desmoulin]

Le 26/03/2016 11:35, Koos Zevenhoven a écrit :
> On Sat, Mar 26, 2016 at 1:56 AM, Chris Angelico <rosuav at gmail.com
> <mailto:rosuav at gmail.com>> wrote:
> [...]
> 
>     If Path objects had universal support in the stdlib *and* significant
>     support in third-party libraries, they could be the one obvious way to
>     do pretty much anything involving paths. 
> 
> 
> True. I suppose many third-party libraries will just work when the
> stdlib functions they use [like open(...) and os.path.join(...)] have
> started accepting Path objects. Then, if a third-party library returns a
> string, one would need to convert it into a path. That is, unless you
> just directly pass it to open(...) or something so you don't care. How
> many reasonably things can a library do with paths without just passing
> them to stdlib functions?
> 
> [...] 
> 
>      Should syntax precede or follow extensive usage?
> 
> 
> Does anything learned from the evolution of string formatting apply here?
>  
> 
>     [1] Overloading division doesn't really do anything for you, other
>     than the way it looks similar to the normal path sep. It's really more
>     of a concatenation operation, which would normally be + not /.
> 
> 
> I agree that joining paths with / is the least interesting feature of
> pathlib.Path. 

Quite the contratry:

- it saves "+" so that "+" still returns a string if needed an not a
Path object, preserving compatibility.

- on the other hand, "/" is garantied to return a Path object, meaning
you can chain the method you listed : Path('test/') / 'foo').method

- it ensure your don't have double "/" around :

>>> Path('test/') / 'foo'
PosixPath('test/foo')

>>> Path('test') / 'foo'
PosixPath('test/foo')

- it will insert "\" if you need it to. Dealing with "\" is really
annoying because it's an escape caracter, so it abstract that for you.

- it marks clearly in the code that you are doing a concatenation of
directories and files, and not something like a prefix, a suffix. You
can spot quickly the places in the code where you deal with hierarchy.

It's a subtile but quite awesome feature.

> 
> Some of this can of course be done with os.path.* too, but here's the
> list of methods and properties on Path:
> 
> ['absolute', 'anchor', 'as_posix', 'as_uri', 'chmod', 'cwd', 'drive',
> 'exists', 'expanduser', 'glob', 'group', 'home', 'is_absolute',
> 'is_block_device', 'is_char_device', 'is_dir', 'is_fifo', 'is_file',
> 'is_reserved', 'is_socket', 'is_symlink', 'iterdir', 'joinpath',
> 'lchmod', 'lstat', 'match', 'mkdir', 'name', 'open', 'owner', 'parent',
> 'parents', 'parts', 'read_bytes', 'read_text', 'relative_to', 'rename',
> 'replace', 'resolve', 'rglob', 'rmdir', 'root', 'samefile', 'stat',
> 'stem', 'suffix', 'suffixes', 'symlink_to', 'touch', 'unlink',
> 'with_name', 'with_suffix', 'write_bytes', 'write_text']
> 
>  - Koos
> 
> 
> 
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