Re: Finding Unused Identifiers

[August Karlstrom <fusionfive@comhem.se>]

Peter Tury wrote:
> As the first easiest(?) step it might help if you generate a list of all
> words what has only one instance in that file (and that instance is in an
> outermost defvar...)? If the list would have a form what is usable in
> compilation mode, then one could go throught it easily and check what
> should really be removed...

I wrote the following, which basically does what I want:

(defconst my-elisp-global-decl-re
   (concat "^[ \t]*("
           (regexp-opt '("defconst" "defimage" "defmacro" "defsubst"
                         "defun" "defvar"))
           "[ \t]+\\<\\(\\w+\\)\\>"))


(defun my-elisp-unused-globals ()
   "Return a list of unused global identifiers.  Returns a list of
global identifiers in the current buffer declared with defconst,
defimage, defmacro, defsubst, defun or defvar that are never
accessed in the same buffer.  Requires that no local identifier
uses the same name as a global identifier."
   (let ((pos nil)
         (res nil)
         (id nil))
     (save-excursion
       (beginning-of-buffer)
       (setq pos (re-search-forward my-elisp-global-decl-re nil t))
       (while (not (null pos))
         (save-excursion
           (setq id (match-string-no-properties 1))
           (setq pos (re-search-forward
                      (concat "\\<" id "\\>") nil t))
           (when (null pos)
             (setq pos (re-search-backward
                        (concat "\\<" id "\\>") nil t 2)))
           (when (null pos)
             (setq res (cons id res))))
         (setq pos (re-search-forward
                    my-elisp-global-decl-re nil t))))
     res))


(defun my-elisp-list-unused-globals ()
   "Display the list returned by `my-elisp-unused-globals'. Output
is written to a separate buffer."
   (interactive)
   (let ((unused-globals (my-elisp-unused-globals))
         (buffer nil))
     (setq buffer (get-buffer-create "*Elisp Unused Globals*"))
     (when (= (count-windows) 1) (split-window))
     (other-window 1)
     (switch-to-buffer buffer)
     (erase-buffer)
     (if (null unused-globals)
         (insert "No unused global identifiers found.")
       (insert "Found unused global identifier(s):\n\n")
       (mapc '(lambda (x) (insert x) (newline)) unused-globals)
       (switch-to-buffer buffer))))


August

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