print ("a is "||a);
type(a, string);
print("c is "||c);
a := 'a':
print ("a is "||a);
type(a, symbol);
unassign('c');
print("c is "||c);
                       "a is Hello World"
                              true
                            "c is 3"
                            "a is a"
                              true
                            "c is c"