[Haskell] Re: Overloading show

karczma karczma at info.unicaen.fr
Fri Sep 10 18:54:07 EDT 2004

Stephan Zaubzer writes: 

> Here my attempts: 
> data Entry a  = EmptyEntry | MakeEntry a a 
> showEntry :: (Show a) => Entry a -> String
> showEntry EmptyEntry = "Empty"
> showEntry MakeEntry a b = show a ++ ": " ++ show b 
> what am I doing wrong? I have seen this way on some tutorials.

I believe that if you looked cautiously at the system response
you would guess yourself. 

Parentheses missing, it should be 

showEntry (MakeEntry a b) = ... 

Jerzy Karczmarczuk 

... who has a pleasure of correcting thousands students' programs
per year, so this kind of error burns his eyes... 

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