eldoc-overlay-mode.el

   1 ;;; eldoc-overlay-mode.el --- Display eldoc with contextual documentation overlay.
   2
   3 ;; Author: stardiviner <numbchild@gmail.com>
   4 ;; Keywords: eldoc overlay
   5 ;; URL: https://github.com/stardiviner/eldoc-overlay
   6 ;; Created: 14th Jan 2017
   7 ;; Version: 0.0.1
   8 ;; Package-Requires: ((emacs "24.3"))
   9
  10 ;;; Commentary:
  11
  12
  13
  14 ;;; Code:
  15 ;;; ----------------------------------------------------------------------------
  16
  17 (defvar eldoc-overlay-display-overlay nil)
  18
  19 (defun eldoc-overlay-delete-string-display ()
  20   (when (overlayp eldoc-overlay-display-overlay)
  21     (delete-overlay eldoc-overlay-display-overlay))
  22   (remove-hook 'post-command-hook 'eldoc-overlay-delete-string-display))
  23
  24 (defun eldoc-overlay-string-display-next-line (string)
  25   "Overwrite contents of next line with STRING until next command."
  26   (let ((str (concat (make-string (1+ (current-indentation)) 32)
  27                      (copy-sequence string)))
  28         start-pos end-pos)
  29     (unwind-protect
  30         (save-excursion
  31           (eldoc-overlay-delete-string-display)
  32           (forward-line)
  33           (setq start-pos (point))
  34           (end-of-line)
  35           (setq end-pos (point))
  36           (setq eldoc-overlay-display-overlay (make-overlay start-pos end-pos))
  37           ;; Hide full line
  38           (overlay-put eldoc-overlay-display-overlay 'display "")
  39           ;; Display message
  40           (overlay-put eldoc-overlay-display-overlay 'before-string str))
  41       (add-hook 'post-command-hook 'eldoc-overlay-delete-string-display))))
  42
  43 (defun eldoc-overlay-display-message-momentary (format-string &rest args)
  44   "Display eldoc message near point."
  45   (when format-string
  46     (eldoc-overlay-string-display-next-line
  47      (apply 'format format-string args))))
  48
  49 (defvar eldoc-overlay-mode-map
  50   (let ((map (make-sparse-keymap)))
  51     map))
  52
  53 (define-minor-mode eldoc-overlay-mode
  54   "Minor mode for displaying eldoc with contextual documentation overlay."
  55   t
  56   :lighter "ElDoc overlay"
  57   :keymap eldoc-overlay-mode-map
  58   :global t
  59   (if eldoc-overlay-mode
  60       (setq eldoc-message-function #'eldoc-overlay-display-message-momentary)
  61     (setq eldoc-message-function #'eldoc-minibuffer-message)
  62     )
  63   )
  64
  65 ;;; ----------------------------------------------------------------------------
  66
  67 (provide 'eldoc-overlay-mode)
  68
  69 ;;; eldoc-overlay-mode.el ends here