[Haskell-cafe] Re: how to see operators precedence in GHCi

Bulat Ziganshin writes:

Hello ,

from http://community.livejournal.com/ru_declarative/54566.html

Q: how to see operators precedence in GHCi? A: Prelude> let showParen = (undefined::[[[[()]]]]->()) Prelude> showParen $ 2+3*4 <interactive>:1:12: No instance for (Num [[[[()]]]]) arising from use of `+' at <interactive>:1:12 Probable fix: add an instance declaration for (Num [[[[()]]]]) In the second argument of `($)', namely `2 + (3 * 4)' In the definition of `it': it = showParen $ (2 + (3 * 4))

Hmm, OK, but not that much quicker than going Prelude> :info (*) class (Eq a, Show a) => Num a where ... (*) :: a -> a -> a ... -- Defined in GHC.Num infixl 7 * Prelude> :info (+) class (Eq a, Show a) => Num a where (+) :: a -> a -> a ... -- Defined in GHC.Num infixl 6 + Prelude> -- Jón Fairbairn Jon.Fairbairn@cl.cam.ac.uk