inspect feature

[George Sakkis]

On Oct 14, 3:06 am, "Gabriel Genellina" <gagsl-... at yahoo.com.ar>
wrote:
> En Fri, 10 Oct 2008 14:18:53 -0300, Aaron "Castironpi" Brady
> <castiro... at gmail.com> escribió:
>
>
>
> > On Oct 10, 3:36 am, Bruno Desthuilliers <bruno.
> > 42.desthuilli... at websiteburo.invalid> wrote:
> >> I don't get what you're after ??? The decorator has full access to both
> >> the actual params *and* the function's signature (via
> >> inspect.getargspec). So your initial question "if you wanted a decorator
> >> that examines the parameters to a function" seems fully answered. You
> >> will indeed have to write a couple lines of code if you want the same
> >> formating as the one you'd get with inspect.currentframe(), but what ?
>
> >> FWIW, Michele Simionato's decorator module has some trick to allow for
> >> signature-preserving decorators, so you may want to have a look - but
> >> I'm not sure if this would solve your problem - at least in a sane way.
>
> > It's not exactly the next Millennium problem, but there are some
> > substantial checks you have to do on a per-parameter basis to see the
> > same thing that a function sees, when all you have is *args, **kwargs.
>
> > You are wrapping a function with this signature:
>
> > def f( a, b, c= None, *d, **e ):
>
> > You want to find out the values of 'a', 'b', and 'c' in a decorator.
> > You have these calls:
>
> > f( 0, 1, 'abc', 'def', h= 'ghi' )
> > f( 0, 1 )
> > f( 0, 1, h= 'abc' )
> > f( 0, 1, 'abc', c= 'def' ) #raise TypeError: multiple values
>
> > How do you determine 'a', 'b', and 'c'?
>
> I'm afraid you'll have to duplicate the logic described here:  http://docs.python.org/reference/expressions.html#id9
> To my knowledge, there is no available Python code (in the stdlib or
> something) that already does that.

I wrote such a beast some time ago; it's hairy but to the best of my
knowledge it seems to reproduce the standard Python logic:
http://code.activestate.com/recipes/551779/

George