tasks a-s

Task/Polymorphism/Ela/polymorphism-1.ela

@@ -0,0 +1,45 @@
+type Point = Point x y
+
+instance Show Point where
+  showf _ (Point x y) = "Point " ++ (show x) ++ " " ++ (show y)
+
+instance Name Point where
+  getField nm (Point x y)
+    | nm == "x" = x
+    | nm == "y" = y
+    | else = fail "Undefined name."
+  isField nm _ = nm == "x" or nm == "y"
+
+pointX = flip Point 0
+
+pointY = Point 0
+
+pointEmpty = Point 0 0
+
+type Circle = Circle x y z
+
+instance Show Circle where
+  showf _ (Circle x y z) =
+    "Circle " ++ (show x) ++ " " ++ (show y) ++ " " ++ (show z)
+
+instance Name Circle where
+  getField nm (Circle x y z)
+    | nm == "x" = x
+    | nm == "y" = y
+    | nm == "z" = z
+    | else = fail "Undefined name."
+  isField nm _ = nm == "x" or nm == "y" or nm == "z"
+
+circleXZ = flip Circle 0
+
+circleX x = Circle x 0 0
+
+circleYZ = Circle 0
+
+circleY y = Circle 0 y 0
+
+circleZ = Circle 0 0
+
+circleEmpty = Circle 0 0 0
+
+circleX 1 2

Task/Polymorphism/Ela/polymorphism-2.ela

@@ -0,0 +1,2 @@
+c = circleX 12
+c.x //Evaluates to 12