Question

I want to concatenate strings in Haskell and also integers
from function like this:

arc 13 34 234 3

13 34 234 3 will be arguments of arc function and I want output like

"arc(13, 34, 234, 3)"

as a String how can I implement this?

Answer 1

If you want String output, the typical technique is to create a ShowS, which is just another name for String -> String.

showsArc :: Int -> Int -> Int -> Int -> ShowS
showsArc a b c d = showString "arc" . shows (a, b, c, d)

>>> showsArc 13 34 234 3 []
"arc(13,34,234,3)"

The [] at the end of the function call is just an empty string. It lets you attach data to the end without worrying about O(N) string concatenation.

>>> showsArc 13 34 234 3 " and some extra text"
"arc(13,34,234,3) and some extra text"