until -package:numeric-prelude -package:util -package:xmonad-contrib -package:LambdaHack -package:prelude-compat -package:basic-prelude -package:snap-core -package:llvm-hs-pure -package:elerea -package:yesod-paginator package:selective
Keep running an effectful computation until it returns a
Right value, collecting the Left's using a supplied
Monoid instance.