I'm looking for a function (perhaps called 'freevars') that does much of the same work as 'freeof', but simply returns a list of all the free variables in an expression. Obviously, 'x' is not free in integrate(x^2,x,0,t), but 't' is.
Thus, every element v in freevars(exp) has not(freeof(v,exp)), and there are no other variables vext not in freevars(exp) such that not(freeof(vext,exp)).
Does such a function exist in Maxima/Macsyma? (It may only be a Lisp function, not a Maxima function; this is ok -- I'll figure out how to call the Lisp function.)