However Emacs is better, cause Steve Yegge says so, and so I switched. I used yasnippet for while, and loved it. It’s a reworking of TextMate’s snippet system with added Lisp; more power without a sacrifice in ease of use. For some reason I stopped using, but since a StackOverflow question recently inspired me, I’m back with a vengence.

A yasnippet to wrap a region or the point in a html tag:

(defun wrap-region-or-point-with-html-tag (start end)
  "Wraps the selected text or the point with a tag"
  (interactive "r")
  (let (string)
    (if mark-active 
        (list (setq string (buffer-substring start end))
          (delete-region start end)))
    (yas/expand-snippet (point)
                        (point)
                        (concat "<${1:p}>" string "$0</${1:$(replace-regexp-in-string \" .*\" \"\" text)}>"))))

(global-set-key (kbd "C-W") 'wrap-region-or-point-with-html-tag)

I wrote this a while, and at the time it was one of the most complicated pieces of Lisp I had written.

I initially misread the StackOverflow question, and submitted the previous function. However once I realised that they wanted something more complex, I felt challenged and dived right in. I eventually came up with this, which hasn’t really been tested:

(defun wrap-lines-in-region-with-html-tag (start end)
  "Wraps the selected text or the point with a tag"
  (interactive "r")
  (let (string)
    (if mark-active 
        (list (setq string (buffer-substring start end))
              (delete-region start end)))
    (yas/expand-snippet
     (replace-regexp-in-string "\\(<$1>\\).*\\'" "<${1:p}>"
      (mapconcat
       (lambda (line) (format "%s" line))
       (mapcar
        (lambda (match) (concat "<$1>" match "</${1:$(replace-regexp-in-string \" .*\" \"\" text)}>"))
        (split-string string "[\r\n]")) "\n") t nil 1) (point) (point))))

From the end of the function working back (which seems to be the way with Functional style), it:

• splits the region by linebreaks
• wraps each line with the yasnippet syntax
• formats each entry as a string
• concatenates all those strings
• replaces the first yasnippet marker with a yasnippet default marker.

I think I should be able to do something better instead of (lambda (line) (format "%s" line)) but I don’t know what.

Definitely the most complex lisp I’ve written to date and I’ve learned quite a lot from writing it.

As always, improvements and suggestions welcome; help yourself to any code.