Re: [Haskell-cafe] Top Level <-

Sittampalam, Ganesh wrote:

Can't you write two recursive modules with <- that depend on each other, so that there's no valid initialisation order?

Contrived example follows:

module Module1 where

glob1 :: IORef Int glob1 <- mod2 >>= newIORef

mod1 :: IO Int mod1 = readIORef glob1

module Module2 where

glob2 :: IORef Int glob2 <- mod1 >>= newIORef

mod2 :: IO Int mod2 = readIORef glob2

Immediatly breaking my promise to shut up.. This is illegal because you're only allowed to use ACIO in top level <- bindings and readIORef isn't (and clearly could not be) ACIO. Regards -- Adrian Hey