Re: [Haskell-cafe] global variables

Taral wrote:

On 5/23/07, Adrian Hey wrote:

...

I think I still prefer..

var :: IORef Int var <- newIORef 3

So do I. For one very good reason: this syntax could be defined as a "constructor" syntax and guaranteed to run before main.

Or even at compile time (which is why I think it's reasonable to regard operations like newIORef etc.. as not really being "IO" operations at all). But anyway, the constraints of the ACIO monad allow creation to occur at any time before the first attempt to read or write the IORef.

The other syntaxes proposed don't strike me as sufficiently rigorous.

Me neither. It's always been a great source of puzzlement to me why this very simple and IMO conservative proposal should be so controversial. Unless someone can point out some severe semantic difficulty or suggest something better it seems like a no-brainer to me. Regards -- Adrian Hey