[Haskell-beginners] Enum for natural numbers

[Brandon S. Allbery KF8NH]

On Dec 17, 2009, at 12:21 , kane96 at gmx.de wrote:
> toEnum should return Z for negative numbers. I did something like  
> this but the problem is I don't know how to set "less than". I tried  
> > and lt:
>
> instance Enum Nat where
>    toEnum (gt 0) = S Z
>    toEnum (lt 1) = Z


Take a look at guards.

-- 
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery at kf8nh.com
system administrator [openafs,heimdal,too many hats] allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon university    KF8NH


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