Add more benchmarks.

benches/iterations.rs

@@ -3,7 +3,7 @@
 ///! Test 1,000 iterations
 extern crate test;
 
-use rhai::{Engine, OptimizationLevel};
+use rhai::{Engine, OptimizationLevel, Scope, INT};
 use test::Bencher;
 
 #[bench]
@@ -23,3 +23,27 @@ fn bench_iterations_1000(bench: &mut Bencher) {
 
     bench.iter(|| engine.consume_ast(&ast).unwrap());
 }
+
+#[bench]
+fn bench_iterations_fibonacci(bench: &mut Bencher) {
+    let script = r#"
+        fn fibonacci(n) {
+            if n < 2 {
+                n
+            } else {
+                fibonacci(n-1) + fibonacci(n-2)
+            }
+        }
+    "#;
+
+    let mut engine = Engine::new();
+    engine.set_optimization_level(OptimizationLevel::None);
+
+    let ast = engine.compile(script).unwrap();
+
+    bench.iter(|| {
+        engine
+            .call_fn::<_, INT>(&mut Scope::new(), &ast, "fibonacci", (20 as INT,))
+            .unwrap()
+    });
+}