Use Haskell to display a ByteString as hex

bytestringToHex.hs

-- can be used in ghci
import qualified Data.ByteString as B
import Numeric (showHex)
import qualified Data.ByteString.Lazy as LBS
import qualified Data.Binary               as B

-- encode some object to a binary ByteString
let s = (B.encode someObjectThatHasBinaryInstance)

let prettyPrint = P.concatMap ((\x -> "0x"++x++" ") . flip showHex "") . B.unpack :: B.ByteString -> String

prettyPrint (LBS.toStrict s)

prettyPrint :: ByteString -> String
prettyPrint = B.foldr showHex ""

original example:

GHCi> prettyPrint "ab\0"
"0x61 0x62 0x0 "

1st comment code:

GHCi> prettyPrint "ab\0"
"61620"

I would have expected "616200". Maybe 0-padding to two hex digits is missing?

{-# LANGUAGE OverloadedStrings #-}
import qualified Data.Text as T
import Data.Text (Text)
import Text.Printf
import Data.ByteString.Lazy (ByteString)
import qualified Data.ByteString.Lazy as B

toHexString :: ByteString -> Text
toHexString = B.foldr (\b -> (<>) (T.pack $ printf "%02x" b)) ""

This one seemed to work for me, but requires Printf.