chapter16: added 3 exercises from heavy lifting exercise

Author: mukeshsoni

chapter16/heavy_lifting.hs

@@ -0,0 +1,23 @@
+-- Instructions
+-- Add fmap, parentheses, and function composition to the expression
+-- as needed for the expression to typecheck and produce the 
+-- expected result.
+
+-- 1. a = (+1) $ read "[1]" :: [Int]
+a :: [Int]
+a = fmap (+1) $ (read "[1]" :: [Int])
+
+-- 2. b = (++ "lol") (Just ["Hi,", "Hello"])
+-- Expected value of b is Just ["Hi,lol", "Hellolol"]
+b :: Maybe [ String ]
+b = (fmap . fmap) (++ "lol") (Just ["Hi", "Hello"])
+
+-- 3. c = (*2) (\x -> x - 2)
+-- Preluce> c 1
+-- -2
+-- Solution Note - This one is tricky since the fmap is happening over the function functor (yes, no typo there)
+c = fmap (*2) (\x -> x - 2)
+
+main = do
+    putStrLn (show a)
+    putStrLn (show b)