[Haskell-cafe] Execution Contexts

[Benjamin Franksen]

On Sunday 28 November 2004 13:53, Keean Schupke wrote:
> ... here is an example object
> in actuall Haskell code using the HList library...
>
>  >point = do
>  >      x <- newIORef 0
>  >      returnIO $ mutableX .=. x
>  >       .*. getX .=. readIORef x
>  >       .*. moveD .=. (\d -> modifyIORef x ((+) d))
>  >       .*. emptyRecord
>
> And here's the object in use:
>  >myFirstOOP = do
>  >     p <- point
>  >     p # getX >>= print
>  >     p # moveD $ 3
>  >     p # getX >>= print
>
> As you can see no lifting or awkwardness involved... the syntax looks
> very much like the OCaml example it was ported from.

Very nice. This would be enough for single threaded programs and as long as 
the local state is simple.

I think it would get quite awkward as soon as you want to provide

- more mutable members
- synchronized access + asynchronous methods

(i.e. _reactive_ objects)

I am ready to be proved wrong, though.

Ben