Function argument conformity check

[crazychimp132 at gmail.com]

On Jun 18, 5:05 pm, George Sakkis <george.sak... at gmail.com> wrote:
> On Jun 18, 3:41 pm, dlists.... at gmail.com wrote:
>
>
>
> > On Jun 18, 3:13 pm, Cédric Lucantis <o... at no-log.org> wrote:
>
> > > Hi,
>
> > > Le Wednesday 18 June 2008 20:19:12 dlists.... at gmail.com, vous avez écrit :
>
> > > > Hi. I am looking for a way to check if some given set of (*args,
> > > > **kwds) conforms to the argument specification of a given function,
> > > > without calling that function.
>
> > > > For example, given the function foo:
> > > > def foo(a, b, c): pass
>
> > > > and some tuple args and some dict kwds, is there a way to tell if i
> > > > _could_ call foo(*args, **kwds) without getting an exception for those
> > > > arguments? I am hoping there is a way to do this without actually
> > > > writing out the argument logic python uses.
>
> > > Each function object is associated to a code object which you can get with
> > > foo.func_code. Two of this object's attributes will help you: co_argcount and
> > > co_varnames. The first is the number of arguments of the function, and the
> > > second a list of all the local variables names, including the arguments
> > > (which are always the first items of the list). When some arguments have
> > > default values, they are stored in foo.func_defaults (and these arguments are
> > > always after non-default args in the co_argnames list).
>
> > > Finally, it seems that some flags are set in code.co_flags if the function
> > > accepts varargs like *args, **kwargs, but I don't know where these are
> > > defined.
>
> > > Note that I never found any doc about that and merely guessed it by playing
> > > with func objects, so consider all this possibly wrong or subject to change.
>
> > > --
> > > Cédric Lucantis
>
> > I am aware of these attributes, although you can get them all in a
> > more organized form using the getfullargspec function in the inspect
> > module from the standard library.
>
> > The problem is that using these attributes, I would essentially have
> > to re-write the logic python uses when calling a function with a given
> > set of arguments. I was hoping there is a way to get at that logic
> > without rewriting it.
>
> Sure; copy it from someone that has already done it ;-)
>
> http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/551779
>
> HTH,
> George

This is exactly what I was looking for- thanks!