So I'm learning Haskell and have a broader programm which i want to run, but I managed to narrow down why it doesn't work to this problem:
putSentence:: String -> IO ()
putSentence sentence = print sentence
func 0 = putSentence "Sample Text."
func x = if 3 == x then putSentence "Three." func (x-1) else putSentence "Not three." func (x-1)
The above code doesn't compile because putSentence takes the following func (x-1) as an additional argument. This is the first time Haskell did it like that for me, and I already tried shuffling the priority around with parentheses and $, but didn't find a way to fix it, so help would be appreciated.
The expression
putSentence "Three." func (x-1)
calls putSentence with three arguments: "Three.", func, and (x-1). This is wrong.
What you probably want to do is to perform the IO actions one after another. For that you can use >>:
putSentence "Three." >> func (x-1)
Alternatively, use a do block:
do putSentence "Three."
func (x-1)
E.g.
func x = if 3 == x
then do
putSentence "Three."
func (x-1)
else do
putSentence "Not three."
func (x-1)