Isaac Dupree wrote:
var :: IORef Int var = {-# EVALUATE_THIS_TEXT_ONLY_ONCE #-} (unsafePerformIO (newIORef 3))
I think I still prefer.. var :: IORef Int var <- newIORef 3 or, more likely.. var :: IORef Int var <- ACIO.newIORef 3 The <- syntax should make the intended semantics clear and unambiguous, so it becomes the problem of individual implementors (not standards writers) to make sure that whatever optimisations or transformations that may be appropriate for their implementation preserve those semantics. (IOW there's no need to worry about what a pragma really means in operational terms, AFAICS). The ACIO monad also restricts what programmers may use on the rhs of the <-. But if you want a good name for the pragma how about this..
var :: IORef Int var = {-# <- #-} (unsafePerformIO (newIORef 3))
:-) Regards -- Adrian Hey