G'day all. On Thu, Feb 13, 2003 at 02:54:42PM -0500, David Roundy wrote:
That's pretty nice (although not quite as nice as it would be to be able to use real ifs with no extra parentheses). Any idea how to do something like this with a case? http://www.haskell.org/mailman/listinfo/haskell-cafe
In the case of Maybe, what you're really trying to do there is a kind of exception handling. You may or may not be better off using a real exception monad transformer on top of IO (or whatever the underlying monad is). One possibility is Control.Monad.Error (fromt he MTL). Here's another possibility: http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/hfl/hfl/mtl/Negate.hs?rev=1.2 I know this didn't directly answer your question, but it's good to explore the design space. Cheers, Andrew Bromage