问题:

When using the leiningen REPL, is there a way to make a file or ns automatically reload in the repl on file save. Currently I reload the ns by typing the following in the repl - (use 'sample.ns :reload-all).

However can I have it reload automatically on file save ?

回答1:

Clojure-Watch library does what you need. It observes a file and performs some action. In your case, an action would be to reload a namespace from that file. Also, it requires to write some initial code to launch the observer.

This way seems a bit complicated to me. Plain REPL launched directly from Lein is not effective way to develop. You better to use some Clojure-friendly editor like Emacs or Lightable.

回答2:

Most major editors support custom hotkey bindings and have a Clojure plugin that allows you to connect to the active REPL over the network (via "nREPL"). Personally, I use vim and therefore use vim-fireplace for this purpose.

This means you can have a custom hotkey for reloading whatever file you're editing as you edit it. From there, it's typically trivial to add a custom on-save hook that does the reloading.