Hi Jason!
2008/12/22 Jason Dusek
So an iteratee is not like a cursor because it does not "own" the collection -- it just tells us how to step it. The enumerator "owns" the collection and provides a way to scope resource use?
Iteratee does not know anything about resources, it doesn't need to. It is just a function which, given an input stream (which is either EOF, block of data or an IO error string), decides what to do, one of: * yield with some (useful) results (and with the rest of the input) * request more input by returning a continuation The enumerator on the other hand, decides when to open the resource (a file, for example), when to close it, and how to "step" through it. Iteratee only gets the fruits of this hard work. :)
it just tells us how to step it
I would say that it just tells us how to react to various forms of input. :) This is much like the function you pass to foldr. I hope this clarifies iteratees a bit (and that my understanding is correct). Cheers, Artyom Shalkhakov.