[Haskell-cafe] Re: [Haskell] Top Level <-

Judah Jacobson wrote:

I've been wondering: is there any benefit to having top-level ACIO'd <- instead of just using runOnce (or perhaps "oneshot") as the primitive for everything?

I don't think oneshots are very good for open witness declarations (such as the open exceptions I mentioned originally), since there are pure functions that do useful things with them. Not sure about TVars either, which operate in the STM monad. Would you also need a oneshotSTM (or a class)? -- Ashley Yakeley