December 28, 2015 07:37 · Dec 28, 2015
diff --git a/playground.rs b/playground.rs
@@ -0,0 +1,41 @@
+#[derive(Clone, Copy)]
+struct Comp;
+struct USB;
+struct Card;
+
+impl USB {
+    fn get_version(&self) -> Option<f64> {
+        Some(1.2)
+    }
+}
+
+impl Card {
+    fn get_usb(&self) -> Option<USB> {
+        Some(USB)
+    }
+}
+
+impl Comp {
+    fn get_soundcard(&self, number: i32) -> Option<Card> {
+        match number {
+            0 => Some(Card),
+            _ => None,
+        }
+    }
+}
+
+fn get_version(computer: Comp, card_number: i32) -> Option<f64> {
+    computer.get_soundcard(card_number)
+            .and_then(|card| card.get_usb())
+            .and_then(|usb| usb.get_version())
+}
+
+fn main() {
+    let computer = Comp;
+
+    let version = get_version(computer, 0);
+    println!("{:?}", version);
+
+    let version = get_version(computer, 1);
+    println!("{:?}", version);
+}