2 forall - to evaluate a function for all values of a list or matrix
14 In forall(x,y), y is the name of a function; that function
15 is performed in succession for all elements of x. This is similar
16 to modify(x, y) but x is not changed.
20 > define s(a) {n += a;}
26 > define e(a) {if (iseven(a)) print a;}