[comp.lang.misc] Yields clause in CLU

news@santra.UUCP (news) (04/14/88)

Why is the "Yields" clause in the iterator abstraction in CLU optional.
This means that I can write an iterator abstraction that is not meant to
return any object, but rather for its side-effect. 
Isn't that contradictory with the idea of an iterator abstraction?