[Haskell-cafe] Tail recursive

[J.W. Krol]

From: jkrzzz at live.com
To: haskell-cafe at haskell.org
Subject: Tail recursive
Date: Wed, 19 Dec 2012 17:07:14 +0100




Hello,
I need a non tail recursive version of scanl, to produce a large enough list of >100K vectors (vectors defined as a list)
I have following code:
scanl'::(a -> a -> a) -> a -> [a] -> [a]scanl' f q ls      = scanl'' ls (q:[]) where											scanl'' (x:xs) ys = let 																	h   = head ys																	x'  = f x h																	ys' = x':ys																	in h `seq` x' `seq` ys' `seq` scanl'' xs ys'											scanl'' [] ys = ys
If I call this function as below I still got stack-overflow error:
head (scanl' (zipWith (+)) ([0,0]) (take 100000 (repeat [0,1])))

What do I wrong. I am not an experienced Haskell programmer, but find the behavior quite unexplainable.
Thank for your answer.
RegardsJacq

 		 	   		   		 	   		  
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