General :: Shifting Positional Parameter Inside A Function?

I need to shift the positional parameters of a script inside a function, but any call to "shift 1" inside a function shifts only the parameters of that function. Is there some way of accomplishing that? I tried another approach using an alias. The problem is that I have to take the result of the alias. So I call in my script:

Code:

var=$(shiftalias)

At first time, it works correctly, but after that it does not shift the parameters anymore.