[Haskell-cafe] nested maybes

[Martin DeMello]

On 2/5/07, Bulat Ziganshin <bulat.ziganshin at gmail.com> wrote:
> Hello J.,
>
> Sunday, February 4, 2007, 11:46:57 PM, you wrote:
>
> > exists s wmap = isJust $ find (==s) . snd =<< Map.lookup (sort s) wmap
>
> exists s wmap =      Map.lookup (sort s) wmap
>                 >>== snd
>                 >>== find (==s)
>                 >>== isJust
>
> a>>==b = a>>=return.b

Very nice! Didn't know about >>==. Thanks to everyone else who
responded too; I'm learning a lot from this thread.

martin