anythingから、ローカルにあるrubygemsのソースを開く ref: http://qiita.com/items/7a832e99d18cc8e507fd

file0.lisp

(defvar anything-c-sources-local-gem-file
  '((name . "gems (local)")
    (candidates-in-buffer)
    (init . (lambda ()
              (unless (anything-candidate-buffer)
                (call-process-shell-command
                 "gem list" nil (anything-candidate-buffer 'global)
                 ))))
    (action . (lambda (gem-name)
                (setq gem-name (replace-regexp-in-string "\s+(.+)$" "" gem-name))
                (with-temp-buffer
                  (call-process "gem" nil t nil "which" gem-name)
                  (let ((path (buffer-substring-no-properties (point-min)
                                                              (- (point-max) 1))))
                    (if (file-exists-p path)
                        (find-file path)
                      (message "no such file or directory:\"%s\"" path))))
                ))))

(defun anything-local-gems ()
  (interactive)
  (anything-other-buffer
   '(anything-c-sources-local-gem-file)
   "*anything local gems*"
  ))