Compojure

One of the great advantages of programming in Clojure is being able to develop software interactively. With Clojure, you can see the effects of your changes to the source code just by reloading the namespace. There is no need to restart the environment, or spend time waiting on lengthy compile times.

To do this in Compojure, we need to ensure the Ring adapter doesn't block the interpreter. We can do this by placing the adapter in a background thread.

Second, we need to ensure that if we reload the handler namespace, the adapter will take code from the updated handler. Rather than passing the handler function directly to the adapter, we can pass a var instead, which will always refer to the latest handler.

Here is an example:

(future (run-jetty (var your-app) {:port 8080}))

Any time the your-app handler function changes, those changes will be displayed automatically next time you refresh your browser.