diff options
Diffstat (limited to 'Haskell-book/08/src')
| -rw-r--r-- | Haskell-book/08/src/Exercises.purs | 72 | ||||
| -rw-r--r-- | Haskell-book/08/src/Main.purs | 9 | ||||
| -rw-r--r-- | Haskell-book/08/src/WordNumber.purs | 30 |
3 files changed, 111 insertions, 0 deletions
diff --git a/Haskell-book/08/src/Exercises.purs b/Haskell-book/08/src/Exercises.purs new file mode 100644 index 0000000..12460a8 --- /dev/null +++ b/Haskell-book/08/src/Exercises.purs @@ -0,0 +1,72 @@ +module Exercises where + +import Data.Tuple (Tuple(..), fst, snd) +import Prelude + +-- +-- Reviewing currying +-- +cattyConny :: String -> String -> String +cattyConny x y = x <> " mrow " <> y + +flippy :: String -> String -> String +flippy = flip cattyConny + +appedCatty :: String -> String +appedCatty = cattyConny "woops" + +frappe :: String -> String +frappe = flippy "haha" + +-- +-- Recursion +-- +-- Exercise 2 +sumNumbers :: Int -> Int +sumNumbers x = sumNumbers' x 0 + where sumNumbers' 0 acc = 0 + sumNumbers' n acc = n + (sumNumbers' (n - 1) acc) + +-- Exercise 2 +multiply :: Int -> Int -> Int +multiply _ 0 = 0 +multiply x 1 = x +multiply x y = x + multiply x (y - 1) + +-- +-- Fixing dividedBy +-- +data DividedResult = + Result Int + | DividedByZero + +instance showDividedResult :: Show DividedResult where + show :: DividedResult -> String + show (Result n) = show n + show DividedByZero = show "Divided by zero" + +go :: Int -> Int -> Int -> Tuple Int Int +go n d count + | n < d = Tuple count n + | otherwise = go (n - d) d (count + 1) + +abs :: Int -> Int +abs x + | x < 0 = -x + | otherwise = x + +dividedBy :: Int -> Int -> Tuple DividedResult DividedResult +dividedBy num denom + | denom == 0 = Tuple DividedByZero DividedByZero + | (num * denom) < 0 = let tuple = go (abs num) (abs denom) 0 in + Tuple (Result (-(fst tuple))) (Result (snd tuple)) + | otherwise = let tuple = go (abs num) (abs denom) 0 in + Tuple (Result (fst tuple)) (Result (snd tuple)) + +-- +-- McCarthy 91 function +-- +mc91 :: Int -> Int +mc91 n + | n > 100 = n - 10 + | otherwise = mc91 (mc91 (n + 11)) diff --git a/Haskell-book/08/src/Main.purs b/Haskell-book/08/src/Main.purs new file mode 100644 index 0000000..abe68ec --- /dev/null +++ b/Haskell-book/08/src/Main.purs @@ -0,0 +1,9 @@ +module Main where + +import Prelude +import Control.Monad.Eff (Eff) +import Control.Monad.Eff.Console (CONSOLE, log) + +main :: forall e. Eff (console :: CONSOLE | e) Unit +main = do + log "Hello sailor!" diff --git a/Haskell-book/08/src/WordNumber.purs b/Haskell-book/08/src/WordNumber.purs new file mode 100644 index 0000000..5d73db5 --- /dev/null +++ b/Haskell-book/08/src/WordNumber.purs @@ -0,0 +1,30 @@ +module WordNumber where + +import Data.Array (reverse) +import Data.Maybe (Maybe(..)) +import Data.String (joinWith) +import Data.Tuple (Tuple(..)) +import Data.Unfoldable (unfoldr) +import Prelude + +digitToWord :: Int -> String +digitToWord 0 = "null" +digitToWord 1 = "one" +digitToWord 2 = "two" +digitToWord 3 = "three" +digitToWord 4 = "four" +digitToWord 5 = "five" +digitToWord 6 = "six" +digitToWord 7 = "seven" +digitToWord 8 = "eight" +digitToWord 9 = "nine" +digitToWord _ = "" + +digits :: Int -> Array Int +digits n = reverse $ unfoldr unfold n + where unfold x + | x == 0 = Nothing + | otherwise = Just (Tuple (mod x 10) (div x 10)) + +wordNumber :: Int -> String +wordNumber n = joinWith "-" $ map digitToWord (digits n) |
