Type mismatch with function

Question

I made the following code:

formateaAux2::[String] -> [String]
formateaAux2 xs = map (++ " ") xs

formateaAux1::[String] -> Int -> [String]
formateaAux1 xs n 
            |n > 0 = do 
                       x <- (formateaAux2(take n xs)) ++ (drop (length(xs) - n) xs)
                       formateaAux1 x (n - length(xs)) -- where it errors
            |n <= 0 = []
formateaAux1 [] _ = []

The purpose of these functions is the following:

• formateaAux2 takes a list of strings and adds a blank space " " to each element in it. (works OK)
• formateaAux1 is supposed to take a list of strings and a number, and use formateaAux2 on n words. If n is greater than the number of words in the list, it'll repeat the same process until n = 0.

Imagine the list of strings is ["Hello", "World"] and n is 4, the objective would be to have as output ["Hello ", "World "], with two blank spaces after each word. If n were 3, then only "Hello" would have two spaces after it, "World" only have one.

So far so good, but I'm getting the following type error telling me that in formateaAux1 x (n - length(xs)), the code expects x to be of type [String] and yet it only gets String. However x should be of type [String] since I'm concatenating a list made from formateaAux2 (which returns [String]) and the higher order function drop, right?

Been at this for a while and I don't know where to look at anymore (though it's probably something trivial), any help is appreciated!

Answer 1

Thanks to what @chi said:

formateaAux2::[String] -> [String]
formateaAux2 xs = map (++ " ") xs


formateaAux1::[String] -> Int -> [String]
formateaAux1 xs n 
            |n > 0 = let x = (formateaAux2(take n xs)) ++ (drop n xs) in
                       formateaAux1 x (n - length(xs))
            |n <= 0 = xs
formateaAux1 [] _ = []