tmp.hs

data Thing = Thing
  { _foo :: Int
  , _bar :: String }
  
buildFoo :: Other -> Thing
buildfoo = Thing <$> buildFoo
                 <*> buildBar
  where buildFoo :: Other -> Int
        buildFoo = undefined
        buildBar :: Other -> String
        buildBar = undefined
        

buildThingThatMightError :: Other -> Either String Thing
buildThingThatMightError = undefined -- ?????
  where buildFoo :: Other -> Either String Int
        buildFoo = undefined
        buildBar :: Other -> Either String String
        buildBar = undefined
        
-- Switch to Either applicative like this
buildThingThatMightError' other = Thing <$> buildFoo other
                                        <*> buildBar other