until -package:numeric-prelude -package:util -package:xmonad-contrib -package:base-compat -package:rebase -package:llvm-hs-pure -package:sparse-linear-algebra package:selective

untilRight :: (Monoid a, Selective f) => f (Either a b) -> f (a, b)
selective Control.Selective
Keep running an effectful computation until it returns a Right value, collecting the Left's using a supplied Monoid instance.