Get actual call signature?

[George Sakkis]

On Mar 18, 6:40 am, Jarek Zgoda <jzg... at o2.usun.pl> wrote:
> Say, I have a function defined as:
>
> def fun(arg_one, arg_two='x', arg_three=None):
>     pass
>
> Is there any way to get actual arguments that will be effectively used
> when I call this function in various ways, like:
>
> fun(5) => [5, 'x', None]
> fun(5, arg_three=['a', 'b']) => [5, 'x', ['a', 'b']]
> fun(5, 'something') => [5, 'something', None]
>
> (et caetera, using all possible mixes of positional, keyword and default
> arguments)
>
> I'd like to wrap function definition with a decorator that intercepts
> not only passed arguments, but also defaults that will be actually used
> in execution.
>
> If this sounds not feasible (or is simply impossible), I'll happily
> throw this idea and look for another one. ;)

I also needed this for a typecheck module I had written some time ago.
It is feasible, but it's rather hairy. I can dig up the code, polish
it and post it as a recipe (or maybe as a patch to the inspect stdlib
module where it belongs).

George