Add simple nested router example

examples/simple_nested_router.rs

@@ -0,0 +1,37 @@
+// A `Router`-nesting version of the example `named_path`.
+
+#![feature(async_await, futures_api)]
+
+use tide::{
+    head::{Named, NamedComponent},
+    Router,
+};
+
+struct Number(i32);
+
+impl NamedComponent for Number {
+    const NAME: &'static str = "num";
+}
+
+impl std::str::FromStr for Number {
+    type Err = std::num::ParseIntError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        s.parse().map(|num| Number(num))
+    }
+}
+
+async fn add_two(Named(number): Named<Number>) -> String {
+    let Number(num) = number;
+    format!("{} plus two is {}", num, num + 2)
+}
+
+fn build_add_two<Data: Clone + Send + Sync + 'static>(router: &mut Router<Data>) {
+    router.at("{num}").get(add_two);
+}
+
+fn main() {
+    let mut app = tide::App::new(());
+    app.at("add_two").nest(build_add_two);
+    app.serve("127.0.0.1:8000");
+}