Thank you.

I assumed when I saw this:

"we could use Maybe's mplus to define a function, parent s = (mother s) `mplus` (father s)"

that mplus was *already* present in Maybe.

Michael

--- On Fri, 5/1/09, Neil Mitchell <ndmitchell@gmail.com> wrote:

From: Neil Mitchell <ndmitchell@gmail.com>
Subject: Re: [Haskell-cafe] chr/ord?
To: "michael rice" <nowgate@yahoo.com>
Cc: "haskell-cafe@haskell.org" <haskell-cafe@haskell.org>, "Anton van Straaten" <anton@appsolutions.com>
Date: Friday, May 1, 2009, 6:32 AM

Hi

> But I get this when I try to use it:
>
> sheep.hs:30:22: Not in scope: `mplus'
> [michael@localhost ~]$

You need to import Control.Monad. You can find answers to these sorts
of questions with Hoogle: http://haskell.org/hoogle/?hoogle=mplus

Thanks

Neil