Hello Phlex, Sunday, June 3, 2007, 11:41:29 AM, you wrote:
That's precisely the thing i don't understand. In order to update node 3 with a new pointer, i need to mutate it, so i need to recreate it, and so on up to node 1.
yes, that's true
Now in this exemple, it's ok since that's a regular tree and the process can be automated, but when each node has a different type, it can become quite hairy.
may be all that you need is structure update syntax? data Planet = Planet { age :: Double , weight :: Double ..... } updatePlanet p = p {age=(age p)*2} the same applies to updating nested structures. you just return updated structure on each level of processing -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com