Incremental mark for clojure

tbatchelli.el

;;;;; extend selection in clojure
;;;; from: http://xahlee.org/emacs/syntax_tree_walk.html

(defun semnav-up (arg)
  (interactive "p")
  (when (nth 3 (syntax-ppss))
    (if (> arg 0)
        (progn
          (skip-syntax-forward "^\"")
          (goto-char (1+ (point)))
          (decf arg))
      (skip-syntax-backward "^\"")
      (goto-char (1- (point)))
      (incf arg)))
  (up-list arg))

(defun extend-selection (arg &optional incremental)
  "Mark the symbol surrounding point.
Subsequent calls mark higher levels of sexps."
  (interactive (list (prefix-numeric-value current-prefix-arg)
                     (or (and transient-mark-mode mark-active)
                         (eq last-command this-command))))
  (if incremental
      (progn
        (semnav-up (- arg))
        (forward-sexp)
        (mark-sexp -1))
    (if (> arg 1)
        (extend-selection (1- arg) t)
      (if (looking-at "\\=\\(\\s_\\|\\sw\\)*\\_>")
          (goto-char (match-end 0))
        (unless (memq (char-before) '(?\) ?\"))
          (forward-sexp)))
      (mark-sexp -1))))

(define-key clojure-mode-map [f6] 'extend-selection)