Re: [Haskell-beginners] Getting a variables type as a string at runtime

On Sun, Jan 12, 2014 at 02:04:40PM +0000, Gareth Morgan wrote:

I have a sum type, when the input is type A I want to process it, when it is type B I want to return MyError "Expected type A but actually got type B". However I also have C,D,E,F, etc which should also return similar errors so don't want to hardcode this string.

Would pattern matching be enough for you? i.e. (very crude): data Test = Alfa | Beta | Gamma deriving (Show) testAlfa Alfa = undefined -- put your process function here testAlfa o = error $ "wasn't expecting " ++ show o main = testAlfa Beta