Re: Finding Unused Identifiers

[August Karlstrom <fusionfive@comhem.se>]

Markus Triska wrote:
> The comment "that are never accessed in the same buffer" is also incorrect:
> 
> (defvar falsepositive 0)
> 
> (eval `(print ,(intern (concat "false" "positive"))))
> 
> ==>
> 
> Found unused global identifier(s):
> 
> falsepositive
> 
> 
> Hyphenated identifiers can yield false negatives:
> 
> (defvar has-hyphen 0)
> 
> (print 'has)
> 
> ==>
> 
> No unused global identifiers found.

Thanks Markus for your remarks. When I tested my functions I had 
previously changed the syntax class for `-' to "w" (word) and then 
forgot that, so I never noticed the problem. I wonder why the syntax 
class of dash is not "word" by default in LISP buffers.

Here is a corrected version:

(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 occur only
once in the same buffer.  Requires that no local identifier uses
the same name as a global identifier."
   (let ((pos nil)
         (res nil)
         (id nil)
         (saved-syntax (char-syntax ?-)))
     (modify-syntax-entry ?- "w")
     (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))))
     (modify-syntax-entry ?- (string saved-syntax))
     res))


Regards,

August

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