1 files changed, 42 insertions, 0 deletions
diff --git a/meap/meap-code/ch4/ch4-sat-mailbox.rs b/meap/meap-code/ch4/ch4-sat-mailbox.rs
new file mode 100644
index 0000000..81f292d
--- /dev/null
+++ b/meap/meap-code/ch4/ch4-sat-mailbox.rs
@@ -0,0 +1,42 @@
+
+#[derive(Debug)]
+struct CubeSat {
+  id: u64,
+  mailbox: Mailbox,
+}
+
+#[derive(Debug)]
+struct Mailbox {
+  messages: Vec<Message>,
+}
+
+type Message = String;
+
+struct GroundStation;
+
+impl GroundStation {
+    fn send(&self, to: &mut CubeSat, msg: Message) {
+        to.mailbox.messages.push(msg);
+    }
+}
+
+impl CubeSat {
+    fn recv(&mut self) -> Option<Message> {
+        self.mailbox.messages.pop()
+    }
+}
+
+fn main() {
+    let base = GroundStation {};
+    let mut sat_a = CubeSat { id: 0, mailbox: Mailbox { messages: vec![] } };
+
+    println!("t0: {:?}", sat_a);
+    base.send(&mut sat_a, Message::from("hello there!")); // <1>
+
+    println!("t1: {:?}", sat_a);
+
+    let msg = sat_a.recv();
+    println!("t2: {:?}", sat_a);
+
+    println!("msg: {:?}", msg);
+}