scope of a variable

Dear All:

I am working on annotations for C language. Consider the following example:

void foo() A[x][y] { };

A is a two dimensional array. A[x][y] is an element which is accessed in the foo() method. I want to know whether variables x and y have been predefined or not? How should I proceed in this regard? Which method to call on Declerator during parsing as I have not intention to do semantic analysis at this stage.

Thanks for the help.