[Haskell-cafe] Re: Functional version of this OO snippet

Thomas Davie wrote:

...

You don't even need a type class, a simple data type is enough.

Very true, but I disagree that you've made it functional in any way, IO is all about sequencing things, it's very much not a functional style

...

data Engine = Engine { foo :: IO (), bar :: String -> IO () }

This is much nicer done as functions from String -> String

Sure, I agree. I was just replicating foo and bar from the OP because I don't know what kind of effect he had in mind. I mean, instead of merely mapping each command in isolation, he could want to accumulate a value or read files or something. Regards, H. Apfelmus