[Python-Dev] Proposing "Argument Clinic", a new way of specifying arguments to builtins for CPython

[Antoine Pitrou]

Le Mon, 03 Dec 2012 14:29:35 -0800,
Larry Hastings <larry at hastings.org> a écrit :
> 
>    /*[clinic]
>    dbm.open -> mapping
>    basename=dbmopen
> 
>        const char *filename;
>            The filename to open.

So how does it handle the fact that filename can either be a unicode
string or a fsencoding-encoded bytestring? And how does it do the right
encoding/decoding dance, possibly platform-specific?

>        static char *_keywords[] = {"filename", "flags", "mode", NULL};
> 
>        if (!PyArg_ParseTupleAndKeywords(args, kwargs,
>            "s|si", _keywords,
>            &filename, &flags, &mode))
>            return NULL;

I see, it doesn't :-)

> But the biggest unresolved question... is this all actually a terrible
> idea?

I like the idea, but it needs more polishing. I don't think the various
"duck types" accepted by Python can be expressed fully in plain C types
(e.g. you must distinguish between taking all kinds of numbers or only
an __index__-providing number).

Regards

Antoine.