Now I have one problem (Well 2 really but the second one is just me not having programmed in haskell for so long that I forgot). getLine is used for the sole purpous of stopping the program and allowing the user to read the error message before the window closes but error does not allow me to do that and aparently using a lambda function (As shown below) does not work (It gives error upon compilation
when ((length keyno /= 1) && (keyno /= "1") && (keyno /= "0")) (\_ -> putStrLn "Please input either 0 or 1 as key number"
getLine
exitWith ExitSuccess)
So is there anyway to fix that?
You need a "do" not a lambda ( or use >> ) when (stuff) (do putStrLn "blah" getLine exitWith ExitSuccess) or when (stuff) (putStrLn "blah" >> getLine >> exitWith ExitSuccess)
The second error is that apparenlty (keyno /= "1") and (keyno /= "0") do not work, but I suspect that, like Java, one can't compare strings using = sign or am I wrong?
No, that should work. Haskell equality is not at all like Java equality. In java, '=' basicaly means pointer equality. I am not aware of a way to even make that comparison in Haskell (in general). Haskell '=' behaves a lot more like equals() in Java. Remove the length test and I think your condition will do what you expect.