There is a special form of comment which should be used with great care. Here is an illustration:
Everything between the ``/* ... */'' will be ignored by Prolog. It is best to put this just before the code discussed.
we now define append/3 so that
it can be used as a generator
The danger is that the programmer might forget to close off an opened comment which normally has disastrous consequences. On the positive side, it can be used to comment out chunks of code during program development.