new tasks

Task/Classes/Haskell/classes-3.hs

@@ -0,0 +1,21 @@
+class Example (x) # 'x' is a field in class
+
+  # method definition
+  method double ()
+    return 2 * x
+  end
+
+  # 'initially' block is called on instance construction
+  initially (x)
+    if /x # if x is null (not given), then set field to 0
+      then self.x := 0
+      else self.x := x
+end
+
+procedure main ()
+  x1 := Example ()  # new instance with default value of x
+  x2 := Example (2) # new instance with given value of x
+  write (x1.x)
+  write (x2.x)
+  write (x2.double ()) # call a method
+end