Add threading example.

examples/threading.rs

@@ -0,0 +1,51 @@
+use rhai::{Engine, RegisterFn, INT};
+
+fn main() {
+    // Channel: Script -> Master
+    let (tx_script, rx_master) = std::sync::mpsc::channel();
+    // Channel: Master -> Script
+    let (tx_master, rx_script) = std::sync::mpsc::channel();
+
+    // Spawn thread with Engine
+    std::thread::spawn(move || {
+        // Create Engine
+        let mut engine = Engine::new();
+
+        // Register API
+        // Notice that the API functions are blocking
+        engine
+            .register_fn("get", move || rx_script.recv().unwrap())
+            .register_fn("put", move |v: INT| tx_script.send(v).unwrap());
+
+        // Run script
+        engine
+            .consume(
+                r#"
+                    print("Starting script loop...");
+
+                    loop {
+                        let x = get();
+                        print("Script Read: " + x);
+                        x += 1;
+                        print("Script Write: " + x);
+                        put(x);
+                    }
+                "#,
+            )
+            .unwrap();
+    });
+
+    // This is the main processing thread
+
+    println!("Starting main loop...");
+
+    let mut value: INT = 0;
+
+    while value < 10 {
+        println!("Value: {}", value);
+        // Send value to script
+        tx_master.send(value).unwrap();
+        // Receive value from script
+        value = rx_master.recv().unwrap();
+    }
+}