IO as a side-effect

Question

Am I able to write a function executing IO as a side-effect of it? For example:

f :: Int -> Int
f n = putStr "text" >> return n*2

Obviously I don't have any way to write that code without it being completely incorrect, but that should at least show roughly what I'm looking to do.

Answer 1

Your function is almost right. If it has a side effect then it needs type IO. Also, function application binds tighter than infix. Fixing these results in:

f :: Int -> IO Int
f n = putStr "text" >> return (n*2)