Xah Talk Show 2022-01-22 emacs lisp coding narrow-to-region, sort-lines, hilight-unicode, emacs vs xemacs

54:03 emacs vs xemacs, richard stallman, open source schism

write xah-narrow-to-region. if no region, just current text block. put in Xah Fly Keys, give it a key.
write xah-sort-lines, that works on current block if no region. put in Xah Fly Keys, give it a key.
write xah-hilight-unicode

(defun xah-narrow-to-region ()
  "Same as `narrow-to-region', but if no selection, narrow to the current block.
Version 2022-01-22"
  (interactive)
  (if (region-active-p)
      (progn
        (narrow-to-region (region-beginning) (region-end)))
    (progn
      (let ($p1 $p2)
        (save-excursion
          (if (re-search-backward "\n[ \t]*\n" nil "move")
              (progn (goto-char (match-end 0))
                     (setq $p1 (point)))
            (setq $p1 (point)))
          (if (re-search-forward "\n[ \t]*\n" nil "move")
              (progn (goto-char (match-beginning 0))
                     (setq $p2 (point)))
            (setq $p2 (point))))
        (narrow-to-region $p1 $p2)))))

(defun xah-sort-lines ()
  "Like `sort-lines' but if no region, do the current block.
Version 2022-01-22"
  (interactive)
  (let ($p1 $p2)
    (let (($bds (xah-get-bounds-of-block-or-region))) (setq $p1 (car $bds) $p2 (cdr $bds)))
    (sort-lines t $p1 $p2)))

(defun xah-hilight-unicode ()
  "Highlight all unicode chars in current buffer or selection.
Version 2022-01-22 2022-01-24"
  (interactive)
  (let ($p1 $p2)
    (if (region-active-p)
        (setq $p1 (region-beginning) $p2 (region-end))
      (setq $p1 (point-min) $p2 (point-max)))
    (save-restriction
      (narrow-to-region $p1 $p2)
      (goto-char (point-min))
      (while (re-search-forward "[^[:ascii:]]+" nil t)
        (put-text-property (match-beginning 0) (match-end 0)  'font-lock-face '(:background  "red"))))))

xah_talk_show_2022-01-22.txt