Dave Bayer wrote:
The code is very fast for its size; I haven't seen Haskell code posted on the web that comes close, and it is faster than any of my other tries (I posted this code to http://www.haskell.org/haskellwiki/Prime_numbers). Effectively, it steals a heap data structure out of thin air by exploiting the implementation of lazy evaluation. It would seem that GHC's core data structures are coded closer to the machine that anything I can write _in_ Haskell. So much for studying how to explicitly write a good heap!
Indeed, it was irritating that I could not make an explicit efficiently-catenable-list data that was nearly as fast as the dlist technique ([a] -> [a]), or even the similarly-performing (forall b. (a -> b -> b) -> b -> b) that does not really take advantage of the heavily optimized [] type. Although, I did not try too hard since the implicit version works just fine. Isaac