In the sense that this blocking can be fully or partially reified. I don't know much about OCaml's implementation of their lwt library, so I'll give an example from Java: In Java you can create a thread running a single subroutine, have that block by calling `park`, and then hold on to that blocked function in a form of a reified object (the thread), which you can resume at any time. This is not possible in Haskell, you cannot hold onto blocked subroutines (i.e. continuations); instead, you hold onto a chain of functions connected via a monad (or monads).
> This is not possible in Haskell, you cannot hold onto blocked subroutines (i.e. continuations); instead, you hold onto a chain of functions connected via a monad (or monads).
I don't understand what this means, and I certainly don't understand the difference between the two things.
This means that Haskell doesn't have an object representing a function blocked in mid-operation. The difference is one of abstraction (obviously all languages can ultimately express all computations), which affects composition and mental overhead. These, of course, are empirical effects, and so their merits cannot be justified on any theoretical grounds (theoretically, monads and continuations are the same).
