Using Alternative <|> to fold nested if

withAlternative.hs

import Control.Monad
import Control.Applicative

checkProperty = undefined

getDmgMult t elem = maybe 1 id $ do
  e <- elem 
  let check f = checkProperty t ((==e) . f) >>= guard
  (check succ >> return 2) `mplus` (check pred >> return 0.5)

getDmgMult t elem = maybe 1 id $ do
  e <- elem 
  let check f = checkProperty t ((==e) . f) >>= guard
  2 <$ check succ <|> 0.5 <$  check pred