[Python-Dev] Positional-only parameters in Python

[Victor Stinner]

2018-01-18 10:26 GMT+01:00 Larry Hastings <larry at hastings.org>:
> Why did Argument Clinic choose that syntax?  It was suggested by one Guido
> van Rossum in March 2012: (...)
> I'm not wading into the debate over what syntax Python should use if it adds
> positional-only parameters, except to say that I think "/" is reasonable.
> If Python winds up using a different syntax, I'd look into modifying
> Argument Clinic so that it accepts both this hypothetical new syntax and the
> existing syntax using "/".

The "/" syntax is used since Python 3.5, at least in some function docstrings:
---
$ python3.5
Python 3.5.4+ (heads/3.5:fd8614c5c5, Dec 18 2017, 12:53:10)
>>> help(abs)
Help on built-in function abs in module builtins:

abs(x, /)
    Return the absolute value of the argument.
---

inspect.signature() is able to parse this syntax, but currently, it is
only used to parse __text_signature__ attribute of builtin functions.

Victor