a monadic if or case?

[Kevin Millikin]

On Thursday, February 13, 2003 8:33 AM, Arjan van IJzendoorn 
[SMTP:afie@cs.uu.nl] wrote:
> Not with the syntactic sugar of 'if'.
> But you can write [warning: untested code ahead]
>
> ifM :: IO Bool -> IO a -> IO a -> IO a
> ifM test yes no = do
>    b <- test
>    if b then yes else no

I had

ifM :: Monad m => m Bool -> m a -> m a -> m a
ifM tst thn els =
  do b <- tst
     if b then thn else els

And I just tested it.

----
Kevin S. Millikin      Architecture Technology Corporation
Research Scientist     Specialists in Computer Architecture
kmillikin@atcorp.com   http://www.atcorp.com