tasks a-s

Task/Polymorphism/E/polymorphism-1.e

@@ -0,0 +1,23 @@
+def makePoint(x, y) {
+  def point implements pbc {
+    to __printOn(out) { out.print(`<point $x,$y>`) }
+    to __optUncall() { return [makePoint, "run", [x, y]] }
+    to x() { return x }
+    to y() { return y }
+    to withX(new) { return makePoint(new, y) }
+    to withY(new) { return makePoint(x, new) }
+  }
+  return point
+}
+
+def makeCircle(x, y, r) {
+  def circle extends makePoint(x, y) implements pbc {
+    to __printOn(out) { out.print(`<circle $x,$y r $r>`) }
+    to __optUncall() { return [makeCircle, "run", [x, y, r]] }
+    to r() { return r }
+    to withX(new) { return makeCircle(new, y, r) }
+    to withY(new) { return makeCircle(x, new, r) }
+    to withR(new) { return makeCircle(x, y, new) }
+  }
+  return circle
+}

Task/Polymorphism/E/polymorphism-2.e

@@ -0,0 +1,4 @@
+def p := makePoint(0.5, 0.5)
+def c := makeCircle(1, 1, 2)
+println(p)
+println(c)