He uses Emacs. He’s also known as snogglethorpe.

miles at

永日の 澄んだ紺から 永遠へ

The code the end of my .emacs file...

   ;; Display "Don't Panic" in large, friendly, letters
   (setq initial-scratch-message
	 (propertize "Don't\nPanic\n"
		     'font-lock-face '(:height 10.0 :inherit variable-pitch))
	 inhibit-startup-screen t)

Some fun little minor modes

   ;;; ----------------------------------------------------------------
   ;;; twisted-mode, Miles Bader <miles /at/>
   (defvar twisted-mode-map
     (let ((map (make-sparse-keymap)))
       (define-key map [remap self-insert-command] 'self-insert-twisted)
       (define-key map [remap delete-backward-char] 'delete-char)
       (define-key map [remap backward-delete-char] 'delete-char)
       (define-key map [remap backward-delete-char-untabify] 'delete-char)
     "Keymap for `twisted-mode'.")
   (define-minor-mode twisted-mode
     "When enabled, self-inserting characters are inserted in \"twisted\" form
   See the variable `twisted-mapping' for the mapping used."
     :lighter " pǝʇsᴉʍT")
   (defvar twisted-mapping
     '((?a . ?ɐ) (?b . ?q) (?c . ?ɔ) (?d . ?p)
       (?e . ?ǝ)           (?g . ?ᵷ) (?h . ?ɥ)
       (?i . ?ᴉ)           (?k . ?ʞ) ;(?l . ?ꞁ)
       (?m . ?ɯ) (?n . ?u)            (?p . ?d)
       (?q . ?b) (?r . ?ɹ)           (?t . ?ʇ)
       (?u . ?n) (?v . ?ʌ) (?w . ?ʍ)
       (?y . ?ʎ)
       (?, . ?‘) (?' . ?‚)
       (?. . ?˙) (?? . ?¿) (?! . ?¡)
       (?( . ?)) (?) . ?() (?[ . ?]) (?] . ?[)
       (?< . ?>) (?> . ?<)
       (?“ . ?„)
     "Mapping from normal characters to twisted characters used by `self-insert-twisted'.")
   (defun self-insert-twisted (arg)
     "Like `self-insert-command', but try to insert a twisted variant.
   The mapping from normal character to twisted characters is taken
   from `twisted-mapping'."
     (interactive "p")
     (setq last-command-char
	   (or (cdr (assq last-command-char twisted-mapping))
     (self-insert-command arg)
     (backward-char arg))

   ;;; ----------------------------------------------------------------
   ;;; caps-lock-mode, Miles Bader <miles /at/>
   (defvar caps-lock-mode-map
     (let ((map (make-sparse-keymap)))
       (define-key map [remap self-insert-command] 'self-insert-upcased)
   (define-minor-mode caps-lock-mode
     "When enabled, convert all self-inserting characters to uppercase."
     :lighter " CapsLock")
   (defun self-insert-upcased (arg)
     (interactive "p")
     (setq last-command-char (upcase last-command-char))
     (self-insert-command arg))

   ;;; ----------------------------------------------------------------
   ;;; literal-tab-mode, Miles Bader <miles /at/>
   (defvar literal-tab-mode-map
     (let ((map (make-sparse-keymap)))
       (define-key map [?\t] 'self-insert-command)
   (define-minor-mode literal-tab-mode
     "When enabled, force the TAB key to insert a literal tab character."
     :lighter " LitTab")
   (define-globalized-minor-mode global-literal-tab-mode literal-tab-mode
   (defun turn-on-literal-tab-mode () (literal-tab-mode 1))

Useful. I’ve added it to my .emacs.

Frob for displaying a list of fonts available via font-config

   ;;; ----------------------------------------------------------------
   ;;; list-fonts-display, Miles Bader <>
   (defun list-fonts-display (&optional matching)
     "Display a list of font-families available via font-config, in a new buffer.
   If the optional argument MATCHING is non-nil, only font families
   matching that regexp are displayed; interactively, a prefix
   argument will prompt for the regexp.
   The name of each font family is displayed using that family, as
   well as in the default font (to handle the case where a font
   cannot be used to display its own name)."
       (and current-prefix-arg
	    (read-string "Display font families matching regexp: "))))
     (let (families)
	 (shell-command "fc-list : family" t)
	 (goto-char (point-min))
	 (while (not (eobp))
	   (let ((fam (buffer-substring (line-beginning-position)
	     (when (or (null matching) (string-match matching fam))
	       (push fam families)))
       (setq families
	     (sort families
		   (lambda (x y) (string-lessp (downcase x) (downcase y)))))
       (let ((buf (get-buffer-create "*Font Families*")))
	 (with-current-buffer buf
	   (dolist (family families)
	     ;; We need to pick one of the comma-separated names to
	     ;; actually use the font; choose the longest one because some
	     ;; fonts have ambiguous general names as well as specific
	     ;; ones.
	     (let ((family-name
		    (car (sort (split-string family ",")
			       (lambda (x y) (> (length x) (length y))))))
		   (nice-family (replace-regexp-in-string "," ", " family)))
	       (insert (concat (propertize nice-family
					   'face (list :family family-name))
			       " (" nice-family ")"))
	   (goto-char (point-min)))
	 (display-buffer buf))))

Alternative visual bell; flashes the echo-area in red

    ;; --------------------------------------------------------
    ;; nice little alternative visual bell; Miles Bader <miles /at/>
    (defcustom echo-area-bell-string "*DING* " ;"♪"
     "Message displayed in mode-line by `echo-area-bell' function."
     :group 'user)
    (defcustom echo-area-bell-delay 0.1
     "Number of seconds `echo-area-bell' displays its message."
     :group 'user)
    ;; internal variables
    (defvar echo-area-bell-cached-string nil)
    (defvar echo-area-bell-propertized-string nil)
    (defun echo-area-bell ()
     "Briefly display a highlighted message in the echo-area.
    The string displayed is the value of `echo-area-bell-string',
    with a red background; the background highlighting extends to the
    right margin.  The string is displayed for `echo-area-bell-delay'
    This function is intended to be used as a value of `ring-bell-function'."
     (unless (equal echo-area-bell-string echo-area-bell-cached-string)
       (setq echo-area-bell-propertized-string
                `(space :align-to (- right ,(+ 2 (length echo-area-bell-string)))))
              'face '(:background "red")))
       (setq echo-area-bell-cached-string echo-area-bell-string))
     (message echo-area-bell-propertized-string)
     (sit-for echo-area-bell-delay)
     (message ""))
    (setq ring-bell-function 'echo-area-bell)

Pretty fun !

You wrote the lexical scope branch and I think that was awesome. Can you write about the history of that and the challenges involved? That would be super interesting.