Re: [Haskell-beginners] Simplify (normalize) symbolic polynom-like expression

17 Jun 2012


      On Sun, Jun 17, 2012 at 9:36 AM, Chaddaï Fouché
 wrote:
...
normalize (Sum xs) = case sort . filter (/= I 0) . map normalize $ xs of
 [] -> I 0
 [a] -> a
 ys -> sumPrefix ys
   where
     sumPrefix (I n : I m : ys) = sumPrefix $ I (n+m) : ys
     sumPrefix ys = ys
Sorry I did this a bit too fast...
...
normalize (Sum xs) = case sumPrefix . sort . filter (/= I 0) . map normalize $ xs of
 [] -> I 0
 [a] -> a
 ys -> Sum ys