If I have an EnumeratorT and a corresponding IterateeT I can run them together:
val en: EnumeratorT[String, Task] = EnumeratorT.enumList(List("a", "b", "c"))
val it: IterateeT[String, Task, Int] = IterateeT.length
(it &= en).run : Task[Int]
If the enumerator monad is “bigger” than the iteratee monad, I can use up or, more generally, Hoist to “lift” the iteratee to match:
val en: EnumeratorT[String, Task] = ...
val it: IterateeT[String, Id, Int] = ...
val liftedIt = IterateeT.IterateeTMonadTrans[String].hoist(
implicitly[Task |>=| Id]).apply(it)
(liftedIt &= en).run: Task[Int]
But what do I do when the iteratee monad is “bigger” than the enumerator monad?
val en: EnumeratorT[String, Id] = ...
val it: IterateeT[String, Task, Int] = ...
it &= ???
There doesn’t seem to be a Hoist instance for EnumeratorT, nor any obvious “lift” method.
