Global variables?

[Andrew J Bromage]

G'day all.

On Fri, Jan 31, 2003 at 09:08:22AM +0100, Ralf Hinze wrote:

> John Hughes wrote a nice pearl on the subject, see
> 
> 	http://www.math.chalmers.se/~rjmh/Globals.ps

Nice!  Why isn't RefMonad in hslibs?

Possibly because of the class signature:

	class Monad m => RefMonad m r | m -> r where
		{- etc -}

It makes perfect sense for there to be more than one kind of "ref"
for a given monad.  Indeed, sometimes it's important.  Quite often, I
use a custom ref built on top of IORef which supports Ord, as this is
needed for hash consing.

Cheers,
Andrew Bromage