Solve 'Geometry Basics: Circle Area in 2D' kata

src/Distance.hs

@@ -1,8 +1,8 @@
-module Distance (distance) where
+module Distance (distance, Point(..)) where
 
 -- https://www.codewars.com/kata/58dced7b702b805b200000be/train/haskell
 
-import Preloaded (Point(..))
+data Point = Point {x :: Double, y :: Double} deriving (Show)
 
 distance :: Point -> Point -> Double
 distance p1 p2 = sqrt ((x p1 - x p2) ^ 2 + (y p1 - y p2) ^ 2)

src/Geometry.hs

@@ -0,0 +1,8 @@
+module Geometry (circleArea) where
+
+import Preloaded (Point(..), Circle(..))
+
+-- https://www.codewars.com/kata/58e3f824a33b52c1dc0001c0/train/haskell
+
+circleArea :: Circle -> Double
+circleArea (Circle _ r) = r * r * pi

src/Preloaded.hs

@@ -4,7 +4,7 @@ import Data.List.Split (divvy)
 
 data Shape
   = Rectangle {width, length :: Double}
-  | Circle {radius :: Double}
+  | Circle1 {radius1 :: Double}
   deriving (Eq, Show)
 
 data RPSLS = Rock | Paper | Scissors | Lizard | Spock deriving (Show, Eq)
@@ -30,4 +30,12 @@ isWaveSorted xs
 
 data Tree = Node {val :: Int, left, right :: Maybe Tree}
 
-data Point = Point {x :: Double, y :: Double} deriving (Show)
+data Point = Point 
+  { xValue :: Double
+  , yValue :: Double 
+  } deriving (Show, Eq)
+
+data Circle = Circle
+  { center :: Point
+  , radius :: Double
+  } deriving (Show, Eq)

src/SortByArea.hs

@@ -11,4 +11,4 @@ sortByArea = sortOn toArea
 
 toArea :: Shape -> Double
 toArea (Rectangle a b) = a * b
-toArea (Circle r) = r * r * pi
+toArea (Circle1 r) = r * r * pi

test/DistanceSpec.hs

@@ -1,7 +1,6 @@
 module DistanceSpec (spec) where
 
-import Preloaded (Point(..))
-import Distance (distance)
+import Distance (distance, Point(..))
 import Test.Hspec
 import Control.Monad (unless)
 

test/GeometrySpec.hs

@@ -0,0 +1,18 @@
+module GeometrySpec where
+
+import Geometry (circleArea)
+import Preloaded
+import Test.Hspec
+import Test.Hspec.Codewars
+
+spec :: Spec
+spec = do
+  describe "Fixed Tests" $ do
+    it "circleArea $ Circle (Point 10 10) 30" $ do
+      circleArea (Circle (Point 10 10) 30) `shouldBeApprox` 2827.4333882308138
+    it "circleArea $ Circle (Point 25 (-70)) 30" $ do
+      circleArea (Circle (Point 25 (-70)) 30) `shouldBeApprox` 2827.4333882308138
+    it "circleArea $ Circle (Point (-15) 5) 0" $ do
+      circleArea (Circle (Point (-15) 5) 0) `shouldBeApprox` 0
+    it "circleArea $ Circle (Point (-15) 5) 12.5" $ do
+      circleArea (Circle (Point (-15) 5) 12.5) `shouldBeApprox` 490.8738521234052

test/SortByAreaSpec.hs

@@ -7,7 +7,7 @@ import Test.Hspec
 spec :: Spec
 spec = do
   it "example tests" $ do
-    sortByArea [ Rectangle 4.23 6.43, Circle 1.23, Circle 3.444, Rectangle 1.342 3.212 ]
-      `shouldBe` [ Rectangle 1.342 3.212, Circle 1.23, Rectangle 4.23 6.43, Circle 3.444 ]
-    sortByArea [ Rectangle 2 5, Circle 6 ] `shouldBe` [ Rectangle 2 5, Circle 6 ]
+    sortByArea [ Rectangle 4.23 6.43, Circle1 1.23, Circle1 3.444, Rectangle 1.342 3.212 ]
+      `shouldBe` [ Rectangle 1.342 3.212, Circle1 1.23, Rectangle 4.23 6.43, Circle1 3.444 ]
+    sortByArea [ Rectangle 2 5, Circle1 6 ] `shouldBe` [ Rectangle 2 5, Circle1 6 ]
     sortByArea [] `shouldBe` []