How to avoid stack space overflows?

Question

I\'ve been a bit surprised by GHC throwing stack overflows if I\'d need to get value of large list containing memory intensive elements. I did expected GHC has TCO so I\'ll neve

Answer 1

These links here will give you a good introduction to your problem of too many thunks (space leaks).

If you know what to look out for (and have a decent model of lazy evaluation), then solving them is quite easy, for example:

{-# LANGUAGE BangPatterns #-}                        

import Data.List                                     

fibs' = unfoldr (\(!a,!b) -> Just (a,(b,a+b))) (0,1) 

main = do                                            
    print $ fibs' !! (10^6)  -- no more stack overflow