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

Thanks, that worked!

Note that this isn't quite the right way to represent a poly if you want to get to a canonical representation.

Can you expand a bit more on this? It is not classic poly, but combination of symbolic vars,sums,products and exponentiation operations (in fact, auto-random-generated) 2012/6/17 Chaddaï Fouché :

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...

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normalize (Sum xs) = case sumPrefix . sort . filter (/= I 0) . map normalize $ xs of  [] -> I 0  [a] -> a  ys -> Sum ys