[Haskell-cafe] Re: Fair diagonals

Louis Wasserman wrote:

+1 on Control.Monad.Omega. In point of fact, your diagN function is simply

diagN = runOmega . mapM Omega

You'll find it an interesting exercise to grok the source of Control.Monad.Omega, obviously, but essentially, you're replacing concatMap with a fair (diagonal) traversal order version.

Thanks for the replies! I've looked at Omega but it's not fair enough. The sums of the indices are not non-decreasing: map sum $ runOmega . mapM each $ [[1..], [1..], [1..]] [3,4,4,4,5,5,5,5,6,6,5,6,6,7,7,5,6,7,7,8,8,6,6,7,8,8,9,9,6,7,... Is there another way to use Omega that meets this (very important) criterion or is Omega not the right tool here? Thanks, Martijn.