(original) (raw)

On Apr 6, 2016 12:47 PM, "Brett Cannon" <brett@python.org> wrote:
\>
\>
\>
\> On Wed, 6 Apr 2016 at 10:41 Wes Turner <wes.turner@gmail.com> wrote:
\>>
\>> \* +1 for \_\_path\_\_, \_\_fspath\_\_
\>> (though I don't know what each does)
\>
\>
\> Returns a string representing a file system path.

Why two methods? \_\_uripath\_\_?

(scheme, host (port), path, query, fragment) so, not \_\_uripath\_\_

what would be the difference between \_\_path\_\_ and \_\_fspath\_\_?

>
\>>
\>> \* why not Text(basestring / bytestring) and pathlib.Path(Text)?
\>
\>
\> See the points about next() vs \_\_next\_\_()

Path(b'123') / u'456'

similarly,
Path(b'123') / UTF8 / UTF16

>
\>>
\>> \* are there examples of cases where this cannot be?
\>
\>
\> I don't understand what you think "cannot be".

What one recommends (path.py(str) / str(pathlib.Path()) + getattr) is distinct from what any given programmer chooses to do with their code.

>
\>>
\>> \* if not, +1 for subclassing str/Text
\>>
\>> \* where are the examples of method collisions between the str interface and the pathlib.Path interface?
\>
\>
\> There aren't any and that's partially why some people wanted the str subclass to begin with.
\>
\> Please consider this thread a str-subclass-free zone. This line of discussion is to flesh out the proposal for a path protocol as a proposal against subclassing str, not to settle the whole discussion outright. If you want to continue to debate the subclassing-str side of this please use the other thread.

this seems to be a sudden, arbitrary distinction.

are these proposals necessarily disjoint?

so,
adding getattr(path, '\_\_path\_\_', path) to stdlib and other code is going to prevent which edge cases (before os.path.normpath()\* anyway) for which benefit?

when do I do getattr(path, '\_\_fspath\_\_', path)?

>
\> -Brett
\>
\>>
\>> \* str.\_\_div\_\_ is nonsensical
\>> \* pathlib.Path.\_\_div\_\_ is super-useful

ah, not .\_\_add\_\_() but .append()

I suppose the request here is for the cases which would be prevented (that we need to learn to look for)

>>
\>>
\>>
\>> On Apr 6, 2016 10:10 AM, "Ethan Furman" <ethan@stoneleaf.us> wrote:
\>>>
\>>> On 04/05/2016 11:57 PM, Nick Coghlan wrote:
\>>>>
\>>>> On 6 April 2016 at 16:53, Nathaniel Smith <njs@pobox.com> wrote:
\>>>>>
\>>>>> On Tue, Apr 5, 2016 at 11:29 PM, Nick Coghlan <ncoghlan@gmail.com> wrote:
\>>>
\>>>
\>>>>>> I'd missed the existing precedent in DirEntry.path, so simply taking
\>>>>>> that and running with it sounds good to me.
\>>>>>
\>>>>>
\>>>>> This makes me twitch slightly, because NumPy has had a whole set of
\>>>>> problems due to the ancient and minimally-considered decision to
\>>>>> assume a bunch of ad hoc non-namespaced method names fulfilled some
\>>>>> protocol -- like all .sum methods will have a signature that's
\>>>>> compatible with numpy's, and if an object has a .log method then
\>>>>> surely that computes the logarithm (what else in computing could "log"
\>>>>> possibly refer to?), etc. This experience may or may not be relevant,
\>>>>> I'm not sure -- sometimes these kinds of twitches are good guides to
\>>>>> intuition, and sometimes they are just knee-jerk responses to an old
\>>>>> and irrelevant problem :-)
\>>>>>
\>>>>> But you might want to at least think about
\>>>>> how common it might be to have existing objects with unrelated
\>>>>> attributes that happen to be called "path", and the bizarro problems
\>>>>> that might be caused if someone accidentally passes one of them to a
\>>>>> function that expects all .path attributes to be instances of this new
\>>>>> protocol.
\>>>>
\>>>>
\>>>> sys.path, for example.
\>>>>
\>>>> That's why I'd actually prefer the implicit conversion protocol to be
\>>>> the more explicitly named "\_\_fspath\_\_", with suitable "\_\_fspath\_\_ =
\>>>> path" assignments added to DirEntry and pathlib. However, I'm also not
\>>>> offering to actually \*do\* the work here, and the casting vote goes to
\>>>> the folks pursuing the implementation effort.
\>>>
\>>>
\>>> If we decide upon \_\_fspath\_\_ (or \_\_path\_\_) I will do the work on pathlib and scandir to add those attributes.
\>>>
\>>> --
\>>> \~Ethan\~
\>>> \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
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\>>
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