In Haskell terms, Roc's `Task ok err` is essentially an `IO (Either err ok)` - the only difference between how Roc does it and how Haskell does it is that `Task` bakes in error handling whereas `IO` doesn't. (Plus the syntax sugar being different, of course.)

So the biggest difference is that algebraic effects are a separate language feature, whereas Task (like IO in Haskell) is a plain old type in the standard library that happens to represent effeects.

Incidentally, the Task.await function in Roc is based on Elm's Task.andThen - we just tried out a different name and argument order for it:

https://package.elm-lang.org/packages/elm/core/latest/Task#a...