[Python-Dev] Defining a path protocol (original) (raw)

Chris Barker - NOAA Federal chris.barker at noaa.gov
Wed Apr 6 20:43:42 EDT 2016

Ah, good point. I think that kills path then as an option.

Darn. I really preferred that. Oh well.

fspath

+0.1

But not a big deal. I think this is pretty much for occasional use by library authors, so not a big deal what it is named.

Which also means that I don't think we need a built-in function that calls it, either. How often do people need a stringified-path version of an arbitrary object?

Which makes me think: str() calls str on an arbitrary object, and creates a new string object.

But fspath(), if it exists, would call fspath on an arbitrary object, and create a new string -- not a new Path. That may be confusing...

If we were starting from scratch, I suppose path would return a Path object -- it would be a protocol one could use to duck-type a path.

But since we have history, we are creating a protocol that conforms to the existing string-as-path protocol.

So are we imagining that future libs will be written that only take objects with a fspath method? In which case, do we need to add it to str? In which case, this is all kind of pointless.

Or maybe all future libs will continue to accept either an str or an object with fspath. In which case, this is pretty pointless, too.

I guess what I'm wondering is if we are stuck with str-paths as the lingua-Franca for paths forever. In which case, we should embrace that and just call str() on anything passed in as a path argument.

Sure, then open(3.5) will give you a file not found error, or maybe create a file with a weird name, but really? Who's going to make that mistake and not figure it out really quickly?

-CHB

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