[Haskell-cafe] Monads

[Albert Y. C. Lai]

On 12-09-30 06:33 PM, Jake McArthur wrote:
> When discussing monads, at least, a side effect is an effect that is
> triggered by merely evaluating an expression. A monad is an interface
> that decouples effects from evaluation.

I don't understand that definition. Or maybe I do subconsciously.

I have

s :: State Int ()
s = do { x <- get; put (x+1) }

Is there an effect triggered by merely evaluating s?

I have

m :: IO ()
m = if True then putStrLn "x" else putChar 'y'

Is there an effect triggered by merely evaluating m?

What counts as "evaluate"?