exec/load -path searching and finding libraries

some-misc-fns.el

(defun exec-path-search (regexp)
  (flatten (remove-if-not 'identity
             (mapcar (lambda (dir) (directory-files dir t regexp))
                     exec-path))))

(defun load-path-search (&optional regexp full-path)
  (unless regexp (set 'regexp "elc?$"))
  (uniq (sort (flatten
               (remove-if-not 'identity
                              (mapcar (lambda (dir) (directory-files dir full-path regexp)) load-path)))
              'string-lessp)))

(defun libraries-matching (regexp)
  (uniq (mapcar (lambda (f) (symbolify (file-name-sans-extension (file-name-nondirectory f))))
                (load-path-search (concat regexp ".*elc?$")))))