[duped]

No, the code you're looking at is using a bunch of macros to implement an embeded DSL on top of Rust.

For example this:

    #[get("/echo")]
    fn echo_stream(ws: WebSocket) -> Stream!['static] {
        Stream! { ws =>
            for await message in ws {
                yield message?;
            }
        }
    }

Is not valid Rust code. The `for await message in ws` is particularly egregious.