If I were to have implemented this in code, I would have probably wrapped this into something like Iterator::Simple, which wraps the 'iteratee' into an object, and adds syntactic sugar that sets it up to be accessed with ->next(), <$it>, and other sugar and coercions that help to gloss over some of the details. I believe that the object created by the module would fit the definition of the iterator. I do agree that the function I provided should have probably been referred to in my test code as $cb or some such.