Emacs: is it possible to automatically insert semicolons in js2-mode?

Question

I'm using this superb js2-mode fork, along with autopairs to make Javascript editing awesome in Emacs. However it occurs to me that since js2-mode is a full parser, it should be possible to automatically insert semi-colons whenever I'm in a function calling context.

I thought I'd ask if anyone's looked into this before I dig too much deeper.

What do you mean by "function calling context"? Inside of functions? How would the mechanism for example know whether you want a semicolon after the `return` in `return\n{ ... }`? — Niklas B., Feb 11 '12 at 16:06
Covering all corner cases isn't necessary here. Just when I call `fooFunc(` ");" is automatically inserted, but when I declare `function(`, only ")" is inserted. — event_jr, Feb 11 '12 at 16:58
I have solved this, and will post as a github project when I get some time. It works well, corner cases not withstanding. — event_jr, Feb 24 '12 at 00:54

score 4 · Accepted Answer · edited Mar 25 '15 at 03:00

Here is my code that solves this:

le-js2-mode-setup-partial.el

(defvar js2-semicolon-contexts (list js2-NAME js2-LP js2-SCRIPT js2-CALL js2-BLOCK))
(defun autopair-js2-maybe-insert-semi-colon (action pair pos-before)
  "handler for automatically inserting semi-colon at the end of function call.
"
  ;; (message "node before is %s" (js2-node-type (js2-node-at-point (- (point) 1))))
  ;; (message "action is %s" action)
  ;; (message "pair is %c" pair)
  ;; (message "context is %s" (buffer-substring-no-properties (point-at-bol) (point-at-eol)))
  ;; (message "point is %s" (point))
  (cond ((and (eq action 'opening)
              (eq pair ?\))
             (save-excursion
               (goto-char pos-before)
               (skip-chars-backward " \t")
               ;; (message "node is %s." (js2-node-type (js2-node-at-point (point))))
               (memq (js2-node-type (js2-node-at-point (point))) js2-semicolon-contexts)
               ))
         (save-excursion
           (let ((forward-sexp-function nil))
             (goto-char pos-before)
             (forward-sexp))
           (if (looking-at-p "[^[:graph:]]*$")
             (insert ";"))))))

;;;###autoload
(defun le::js2-mode-setup ()
  (setq autopair-handle-action-fns
        (list #'autopair-default-handle-action
              #'autopair-js2-maybe-insert-semi-colon))
  (rebox-mode 1)
  (le::prog-modes-setup))
;;;###autoload(add-hook 'js2-mode-hook 'le::js2-mode-setup)

You can also get this code from this GitHub Gist.

Emacs: is it possible to automatically insert semicolons in js2-mode?

1 Answers1