08 Sep 2021

a high signal to noise emacs command

Over the years, i've written perhaps hundreds of little emacs commands. Most of them looked useful at the time (why, i absolutely needed them!), but just faded away after a few weeks. There are a handful though that i use all the time, and i specially like it when their signal (features, usefulness) to noise (lines of code) ratio is above average. Here's one with a surprisingly high one:

(defun jao-buffer-same-mode (&rest modes)
  "Pop to a buffer with a mode among MODES, or the current one if not given."
  (interactive)
  (let* ((modes (or modes (list major-mode)))
         (pred (lambda (b)
                 (let ((b (get-buffer (if (consp b) (car b) b))))
                   (member (buffer-local-value 'major-mode b) modes)))))
    (pop-to-buffer (read-buffer "Buffer: " nil t pred))))