Emacs lisp is not multi-threaded. async-eval.el explores possibilities to work around this. It allows forms to be evaluated in a different Emacs process. This means that the executed code cannot access the current environment, and the code’s side effects cannot be used directly. There is a small overhead from starting a new process.
(async-eval
(lambda (result) (message "async result: <%s>" result))
(let ((sum 0)
(i 10000000))
(while (> i 0)
(setq sum (+ sum i)
i (1- i)))
sum))async-eval can take care of exporting function definitions to the new process:
(defun fib (n)
"Intentionally slow fibonacci numbers."
(if (< n 2)
n
(+ (fib (1- n)) (fib (- n 2))))) (async-eval-with-export '(fib)
(lambda (result) (message "async result: <%s>" result))
(fib 30))