(Emacs+Org-Mode) Make Eval Expression A Little Easier

Once you’ve been using Emacs for a while you end up using eval-expression a lot. 99% of the time I use it to make function calls. I never noticed before that it is kind of tedious to reach for S-M-; and then () despite using it so much. Here is a binding and a function definition that make it easier to use binding it close to home and inserting the round parentheses.

(global-set-key (kbd "M-;") #'my-eval-expression)
(define-key org-mode-map (kbd "M-;") nil)
(progn

  (defvar my-read-expression-map
    (let ((map (make-sparse-keymap)))
      (set-keymap-parent map read-expression-map)
      (define-key map [(control ?g)] #'minibuffer-keyboard-quit)
      (define-key map [up]   nil)
      (define-key map [down] nil)
      map))

  (defun my-read--expression (prompt &optional initial-contents)
    (let ((minibuffer-completing-symbol t))
      (minibuffer-with-setup-hook
          (lambda ()
            (emacs-lisp-mode)
            (use-local-map my-read-expression-map)
            (setq font-lock-mode t)
            (funcall font-lock-function 1)
            (insert "()")
            (backward-char))
        (read-from-minibuffer prompt initial-contents
                              my-read-expression-map nil
                              'read-expression-history))))

  (defun my-eval-expression (expression &optional arg)
    "Attribution: URL `https://lists.gnu.org/archive/html/help-gnu-emacs/2014-07/msg00135.html'."
    (interactive (list (read (my-read--expression ""))
                       current-prefix-arg))
    (if arg
        (insert (pp-to-string (eval expression lexical-binding)))
      (pp-display-expression (eval expression lexical-binding)
                             "*Pp Eval Output*"))))

4 thoughts on “(Emacs+Org-Mode) Make Eval Expression A Little Easier”

  1. Great idea! ;-) Another tips to save a little bit of typing is to learn M-(. It takes a bit to get a habit of using it though.

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