[Python-ideas] tweaking the file system path protocol

[Koos Zevenhoven]

On Sun, May 28, 2017 at 9:15 AM, Nick Coghlan <ncoghlan at gmail.com> wrote:
>
> However, if we *did* make such a change, it should also be made for
> operator.index as well, since that is similarly inconsistent with the
> way the int/float/etc constructor protocols work:
>

Part of this discussion seems to consider consistency as the only
thing that matters, but consistency is only the surface here. I won't
comment on the __index__ issue, and especially not call it a
"misfeature", because I haven't thought about it deeply, and my
comments on it would be very shallow. I might ask about it though,
like the OP did.

Don't get me wrong, I like consistency very much. But regarding the
__fspath__ case, there are not that many people *writing*
fspath-enabled classes. Instead, there are many many many more people
*using* such classes (and dealing with their compatibility issues in
different ways). For those people, the current behavior brings
consistency---after all, it was of course designed by thinking about
it from all angles and not just based on my or anyone else's own use
cases only.

-- Koos

>     >>> from operator import index
>     >>> class MyInt(int):
>     ...     def __int__(self):
>     ...         return 5
>     ...     def __index__(self):
>     ...         return 5
>     ...
>     >>> int(MyInt(10))
>     5
>     >>> index(MyInt(10))
>     10
>     >>> class MyFloat(float):
>     ...     def __float__(self):
>     ...         return 5.0
>     ...
>     >>> float(MyFloat(10))
>     5.0
>     >>> class MyComplex(complex):
>     ...     def __complex__(self):
>     ...         return 5j
>     ...
>     >>> complex(MyComplex(10j))
>     5j
>     >>> class MyStr(str):
>     ...     def __str__(self):
>     ...         return "Hello"
>     ...
>     >>> str(MyStr("Not hello"))
>     'Hello'
>     >>> class MyBytes(bytes):
>     ...     def __bytes__(self):
>     ...         return b"Hello"
>     ...
>     >>> bytes(MyBytes(b"Not hello"))
>     b'Hello'
>
> Regards,
> Nick.
>

-- 
+ Koos Zevenhoven + http://twitter.com/k7hoven +