ADT explained proper

101companies · May 21, 2015 · 3f6e56d · 3f6e56d
1 parent b1e3537
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diff --git a/concepts/Abstract_data_type/Point.hs b/concepts/Abstract_data_type/Point.hs
@@ -0,0 +1,12 @@
+module Point(
+  Point, -- constructor is NOT exported
+  mkPoint,
+  getX,
+  getY
+) where
+
+data Point = Point { getX :: Int, getY :: Int }
+  deriving (Eq, Show, Read)
+
+mkPoint :: Int -> Int -> Point
+mkPoint = Point
diff --git a/concepts/Abstract_data_type/PointProperties.hs b/concepts/Abstract_data_type/PointProperties.hs
@@ -0,0 +1,8 @@
+import Point
+import Test.QuickCheck
+
+prop_getX :: Int -> Int -> Bool
+prop_getX x y = getX (mkPoint x y) == x
+
+prop_getY :: Int -> Int -> Bool
+prop_getY x y = getY (mkPoint x y) == y