shapes of justice

src/visitor/Tupfile

@@ -0,0 +1,3 @@
+include_rules
+
+: main.go |> !gccgo |> ../../bin/visitor

src/visitor/main.go

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+package main
+
+// Shape defines the base for shape functions
+type Shape interface {
+	Area() float64
+	Perimeter() float64
+}
+
+type Square struct {
+	Shape
+	Arm float64
+}
+
+func (s *Square) Area() float64 {
+	return s.Arm * s.Arm
+}
+
+func (s *Square) Perimeter() float64 {
+	return s.Arm * 4
+}
+
+type Triangle struct {
+	Shape
+	Base   float64
+	Height float64
+}
+
+func (t *Triangle) Area() float64 {
+	return (t.Base * t.Height) / 2
+}
+
+func (t *Triangle) Perimeter() float64 {
+	return 0.0 // I forgot how to do this from just base and height.
+}
+
+func main() {
+	t := &Triangle{
+		Base:   15,
+		Height: 30,
+	}
+
+	myT := t.(Shape)
+}