That can't, but with https://gist.github.com/605891 you can, using syntax like:

    [(1..6),(4..6),(7..9)].comprehension { |a, b, c| a + b + c if a % 2 == 0 }

And if you go to extremes like https://gist.github.com/3356675 you can use Haskell-like syntax:

    [a + b | a <- ['n','p'..'t'], b <- %w[a i u e o]]

Ruby's blocks and method_missing are very powerful.