[Haskell-cafe] elem of infinite set of tuple

[Dan Doel]

On Friday 16 May 2008, leledumbo wrote:
> I don't know how Haskell should behave on this. Consider this function:
> elemOf (x,y) = (x,y) `elem` [ (a,b) | a <- [0..], b <- [0..] ]

FYI: The control-monad-omega package on hackage.haskell.org can handle this 
sort of thing (liberties taken with ghci formatting):

Prelude> :m + Control.Monad.Omega
Prelude Control.Monad.Omega>
  (1,1) `elem` runOmega (do x <- each [0..] ; y <- each [0..] ; return (x,y))
True
Prelude Control.Monad.Omega>

It does breadth-first instead of depth-first search.
-- Dan