How do I automatically run a binary in the background using Emacs Lisp when in a particular major mode?

Question

I would like to automatically run the purescript language server binary in the background when Emacs loads a .purs PureScript file in PureScript mode. Is there an easy way to do this using Emacs Lisp in my init.el file?

Answer 1

(defun my-program ()
  (message "Start to run my-program")
  ;; Replace with your binary.
  (shell-command "pwd"))
(add-hook 'purescript-mode-hook #'my-program)