[Haskell-cafe] Re: breadth first search one-liner?

[Bertram Felgenhauer]

Bertram Felgenhauer wrote:
> or
>     bfs next start = lefts . takeWhile (not . null)

I copied the wrong version. This should be

    bfs next start = rights . concat . takeWhile (not . null) 
    -- rest unchanged
         . unfoldr (Just . span (either (const False) (const True)) . tail)
         $ fix (nub . (Left 0 :) . (Right start :)
               . (>>= either ((:[]) . Left . succ) (map Right . next)))

Bertram