emacs临时绑定一个elisp函数到某个键组合

(global-set-key (kbd "<f8>")
   (lambda() 
        (interactive)
        (save-buffer)
        (call-process-shell-command "latex -interact=batchmode -output-format=pdf assignment_2")
        (message "having generated pdf successfully")))

必须调用“interactive“函数。