emacsd / init-imenu.el

;;; init-imenu.el
;; Copyright (C) Yagnesh Raghava Yakkala.
;; License: GPL v3 or later

;;; from emacs-starter-kit
(require 'imenu)

(defun ido-imenu ()
  "Update the imenu index and then use ido to select a symbol to navigate to.
Symbols matching the text at point are put first in the completion list."
  (let ((name-and-pos '())
        (symbol-names '()))
    (flet ((addsymbols (symbol-list)
                       (when (listp symbol-list)
                         (dolist (symbol symbol-list)
                           (let ((name nil) (position nil))
                              ((and (listp symbol) (imenu--subalist-p symbol))
                               (addsymbols symbol))

                              ((listp symbol)
                               (setq name (car symbol))
                               (setq position (cdr symbol)))

                              ((stringp symbol)
                               (setq name symbol)
                               (setq position (get-text-property 1 'org-imenu-marker symbol))))

                             (unless (or (null position) (null name))
                               (add-to-list 'symbol-names name)
                               (add-to-list 'name-and-pos (cons name position))))))))
      (addsymbols imenu--index-alist))
    ;; If there are matching symbols at point, put them at the beginning of `symbol-names'.
    (let ((symbol-at-point (thing-at-point 'symbol)))
      (when symbol-at-point
        (let* ((regexp (concat (regexp-quote symbol-at-point) "$"))
               (matching-symbols (delq nil (mapcar (lambda (symbol)
                                                     (if (string-match regexp symbol) symbol))
          (when matching-symbols
            (sort matching-symbols (lambda (a b) (> (length a) (length b))))
            (mapc (lambda (symbol) (setq symbol-names (cons symbol (delete symbol symbol-names))))
    (let* ((selected-symbol (ido-completing-read "Symbol? " symbol-names))
           (position (cdr (assoc selected-symbol name-and-pos))))
      (goto-char position))))

(global-set-key (kbd "C-x C-i") 'ido-imenu)

;;; mail mode
(setq message-imenu-generic-expression
      '(("Subject"  "^\\(Subject:\\).*" 1)
        ("Cc"     "^\\(C[Cc]:\\).*" 1)
        ("To"     "^\\(To:\\).*" 1)
        ("From"  "^\\(From:\\).*" 1)))

(add-hook 'message-mode-hook
          (lambda ()
            (setq imenu-generic-expression message-imenu-generic-expression)))

;;; init-imenu.el ends here