isearch-forward-word が気に入らないので改良版

gistfile1.txt

参考【EmacsWiki: Search At Point】 http://emacswiki.org/emacs/SearchAtPoint

isearch-forward-at-point.el

(defvar isearch-initial-string nil)
(defun isearch-set-initial-string ()
  (remove-hook 'isearch-mode-hook 'isearch-set-initial-string)
  (setq isearch-string isearch-initial-string)
  (isearch-search-and-update))
(defun isearch-forward-at-point (&optional regexp-p no-recursive-edit)
  "Interactive search forward for the symbol at point."
  (interactive "P\np")
  (if regexp-p (isearch-forward regexp-p no-recursive-edit)
	(let* ((end (progn (skip-syntax-forward "w_") (point)))
		   (begin (progn (skip-syntax-backward "w_") (point))))
	  (if (eq begin end)
		  (isearch-forward regexp-p no-recursive-edit)
		(setq isearch-initial-string (buffer-substring begin end))
		(add-hook 'isearch-mode-hook 'isearch-set-initial-string)
		(isearch-forward regexp-p no-recursive-edit)))))
(define-key isearch-mode-map "\C-w" 'isearch-forward-at-point)