replace_program() - replaces the program in this_object()
void replace_program( string str );
replace_program() replaces the program in this_object() with that of an object it inherits. The string argument is the filename of the object whose program is to be used. Once the replacement takes place, the current object effectively becomes a clone of that other object, but with its current filename and global variable values. The program is not actually replaced until the current execution is completed.