Hallo, Suppose a function: def f(param) where the format of the param is a tuple containing lists and tuples e.g. (a,[b,(c,[a,b])]) For efficiency I want to put these functions (I have more than one) into C. How can I best do this? Thanks, Naudts Guido Informaticus Tel. 02/542.76.01 Fax: 02/538.01.80 E-mail: guido.naudts at just.fgov.be