Question

I have a basic function that accepts an Int and returns a list:

generateCode rnd = 
  [sharpOrDot i rnd  | i <- [0..24]]

I call it from my main function like this:

do
  r  <- (randomIO :: IO Int)
  generateCode r

Shouldn’t r <- (randomIO :: Int) “unpack” the Int part from IO Int and hence just pass a Int to generateCode?

It returns the error

Couldn't match expected type `IO a0' with actual type `[Char]'

Thanks

Answer 1

I think the last line must be return (generateCode r). Else your do-block would “break out” of the IO monad, which is impossible (well, without using the function with the name we don’t dare to speak out).