chore: add advanced class example

examples/advanced/02_polymorphism.peb

@@ -0,0 +1,66 @@
+class Shape {
+    init(color) {
+        this.color = color
+    }
+
+    name() {
+        return "shape"
+    }
+
+    area() {
+        return 0
+    }
+
+    describe() {
+        print("A", this.color, this.name(), "with area", this.area())
+    }
+}
+
+class Rectangle < Shape {
+    init(color, width, height) {
+        super.init(color)
+        this.width = width
+        this.height = height
+    }
+
+    name() {
+        return "rectangle"
+    }
+
+    area() {
+        return this.width * this.height
+    }
+}
+
+class Square < Rectangle {
+    init(color, size) {
+        super.init(color, size, size)
+    }
+
+    name() {
+        return "square"
+    }
+}
+
+class Circle < Shape {
+    init(color, radius) {
+        super.init(color)
+        this.radius = radius
+    }
+
+    name() {
+        return "circle"
+    }
+
+    area() {
+        return this.radius * this.radius * 3.1415
+    }
+}
+
+let rect = Rectangle("red", 3, 4)
+let square = Square("green", 5)
+let circle = Circle("blue", 2)
+
+rect.describe()
+square.describe()
+circle.describe()

main.py

@@ -4,7 +4,7 @@ from src.pebble import Pebble
 
 
 def main():
-    path: Path = Path("examples/basic/21_super.peb")
+    path: Path = Path("examples/advanced/02_polymorphism.peb")
     Pebble.run_file(path)