[Haskell-cafe] case of (was: [Haskell] Mixing monadic and non-monadic functions)

[Donn Cave]

On Mon, 19 Sep 2005, Andrew Pimlott wrote:
> On Sat, Sep 17, 2005 at 06:56:36PM +0100, Ben Rudiak-Gould wrote:
> >   * The new syntax is really nice as a replacement for the annoyingly
> >     common "x <- foo ; case x of..." idiom that I've always disliked.
> 
> I might wish for "case of" to mean "\x -> case x of":
> 
>     foo >>= case of ...
> 
> Useful outside of monads, eg to write anonymous functions for map.

The ordinary lambda comes close - in ghc anyway, it supports
pattern matching.  But I can't work out the syntax for multiple
cases, which would obviously be needed to make it practically
useful.

e.g., this seems to be OK:
    getArgs >>= \ (a:_) -> putStrLn (show a)

but how do you write
    getArgs >>= \	[] -> putStrLn "(no arguments)"
			(a:_) -> putStrLn (show a)

(pardon me if I missed where you were going in "case of ...")

	Donn Cave, donn at drizzle.com