A point-free (pointless?) little program to calculate how much to invoice clients to get a desired amount after Stripe's fees.

stripe.hs

module Main where

import System.Environment

main :: IO ()
main = getArgs >>= parse >>= display . roundMoney . charge

charge :: Fractional a => a -> a
charge = (/ 0.971) . (+ 0.3)

display :: Show a => a -> IO ()
display = putStrLn . show

parse :: (Monad m, Read b) => [String] -> m b
parse = return . read . flip (!!) 0

roundMoney :: RealFrac f => f -> f
roundMoney = (/ 10.0 ^^ 2) . fromInteger . round . (100 *)