Re: [Haskell-beginners] A "show" error

I use Hugs.  And I must use it... ________________________________ From: Ozgur Akgun To: bahadýr altan Cc: "beginners@haskell.org" Sent: Sunday, 11 March 2012, 21:26 Subject: Re: [Haskell-beginners] A "show" error Hi again, What interpreter do you use? With ghci, I don't get any errors. *Main> f (Branch 12 (Branch 15 Empty Empty) (Branch 28 Empty Empty)) (12,15,Empty,Empty,28,Empty,Empty) On 11 March 2012 19:10, bahadýr altan wrote: Hi, 

I'm trying to process on a tree with this function :

f (Branch x (Branch y y1 y2) (Branch z z1 z2)) = (x,y,y1,y2,z,z1,z2)

and my tree declaration is this : 

data Tree = Empty | Branch Integer Tree Tree deriving (Show)

And I'm getting this error : 

Main> f (Branch 12 (Branch 15 Empty Empty) (Branch 28 Empty Empty)) ERROR - Cannot find "show" function for: *** Expression : f (Branch 12 (Branch 15 Empty Empty) (Branch 28 Empty Empty)) *** Of type    : (Integer,Integer,Tree,Tree,Integer,Tree,Tree)

I'll be happy if you help me to get rid of this error.. -- Ozgur Akgun