====== Composition operator ======

  * composition operator is "."
  * type: ''(b -> c) -> (a -> b) -> a -> c''
  * takes two functions as parameter and combines the functions
    * first function is applied to the result of the second function
  * example:<code Haskell>
import qualified Data.Char as Ch (ord)

main :: IO ()
main = 
    do
        print $ f3 'a'
        print $ f4 'a'

f1 :: Char -> Integer
f1 ch = toInteger $ Ch.ord(ch)

f2 :: Integer -> Double
f2 n = fromIntegral n :: Double

f3 :: Char -> Double
f3 = f2 . f1

f4 :: Char -> Double
f4 ch = f2 (f1 ch)</code>
    * executes with output:<code>
97.0
97.0
</code>


===== ✎ =====
~~DISCUSSION~~