update doc in lisp file header comments

zero-framework.el

 ;; -*- lexical-binding: t -*-
 ;; the zero Chinese input method framework for emacs.
 ;; implemented as a minor mode.
-;; (load-file "~/lisp/elisp/zero/zero-panel.elc")
-;; (load-file "~/lisp/elisp/zero/zero-framework.elc")
 
 ;;==============
 ;; dependencies

zero-pinyin.el

 ;; -*- lexical-binding: t -*-
 ;; a pinyin input method for zero-framework
+;; use use this input method, add in emacs init file:
+;; (add-to-list 'load-path "~/lisp/elisp/zero")
+;; (require 'zero-pinyin)
+;; (zero-set-default-im 'pinyin)
 
 ;;==============
 ;; dependencies

zero-quickdial.el

 ;; -*- lexical-binding: t -*-
-;; a simple input method written as an emacs minor mode
+;; zero-quickdial input method written as an emacs minor mode.
+;;
+;; to use this input method,
+;; M-x zero-quickdial-mode    ; turn on IM
+;; type 1 will insert one
+;; type 2 will insert two
+;; type 3 will insert three.
+;; M-x zero-quickdial-mode    ; turn off IM
+;;
+;; This is just a demo of how emacs minor mode can work as input method.
 
 (defun zero-quickdial-insert-one ()
   (interactive)
@@ -13,18 +22,17 @@
   (interactive)
   (insert "three"))
 
-(defvar zero-quickdial-mode-map nil "zero-quickdial-mode keymap")
-
-(setq zero-quickdial-mode-map
-      (list 'keymap
-	    '(49 . zero-quickdial-insert-one)
-	    '(50 . zero-quickdial-insert-two)
-	    '(51 . zero-quickdial-insert-three)))
+(defvar zero-quickdial-mode-map
+  '(keymap
+    (49 . zero-quickdial-insert-one)
+    (50 . zero-quickdial-insert-two)
+    (51 . zero-quickdial-insert-three))
+  "zero-quickdial-mode keymap")
 
 (define-minor-mode zero-quickdial-mode
   "a simple input method written as an emacs minor mode"
   nil
-  "Quickdial"
+  " Quickdial"
   zero-quickdial-mode-map)
 
 (provide 'zero-quickdial)

zero-table.el

 ;; -*- lexical-binding: t -*-
-;; a simple input method written as an emacs minor mode
-;; (load-file "~/lisp/elisp/zero/zero-panel.elc")
-;; (load-file "~/lisp/elisp/zero/zero-framework.elc")
-;; (load-file "~/lisp/elisp/zero/zero-table.elc")
+;; a demo table based input method based on zero-framework.el
+;;
+;; when you type the key in `zero-table-table', IM will insert the
+;; corresponding value.
+;;
+;; To use this demo IM,
+;;   (add-to-list 'load-path "~/lisp/elisp/zero")
+;;   (require 'zero-table)
+;;   (zero-set-default-im 'zero-table) ; set as default IM
+;;   or (zero-set-im 'zero-table)      ; set as current buffer's IM
 
 ;;==============
 ;; dependencies