typing-speed.el

;;; typing-speed.el --- Minor mode which displays your typing speed

;; Copyright (C) 2008 Wangdera Corporation

;; Permission is hereby granted, free of charge, to any person
;; obtaining a copy of this software and associated documentation 
;; files (the "Software"), to deal in the Software without 
;; restriction, including without limitation the rights to use, 
;; copy, modify, merge, publish, distribute, sublicense, and/or sell 
;; copies of the Software, and to permit persons to whom the 
;; Software is furnished to do so, subject to the following 
;; conditions:

;; The above copyright notice and this permission notice shall be 
;; included in all copies or substantial portions of the Software.

;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 
;; OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
;; NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
;; HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 
;; WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
;; FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 
;; OTHER DEALINGS IN THE SOFTWARE.

;; Author: Craig Andera <candera@wangdera.com>

;; Commentary: Invoke this minor mode to have your typing speed 
;; continuously displayed in the mode line, in the format [75 WPM] 
;; To use, just load this file and invoke (typing-speed-mode) or 
;; (turn-on-typing-speed-mode)

(define-minor-mode typing-speed-mode 
    "Displays your typing speed in the status bar." 
  :lighter typing-speed-mode-text 
  :group typing-speed 
  (if typing-speed-mode 
      (progn 
    (add-hook 'post-command-hook 'typing-speed-post-command-hook) 
    (setq typing-speed-event-queue '()) 
    (setq typing-speed-update-timer (run-with-timer 0 typing-speed-update-interval 'typing-speed-update))) 
      (progn 
    (remove-hook 'post-command-hook 'typing-speed-post-command-hook) 
    (cancel-timer typing-speed-update-timer))))

(defcustom typing-speed-window 5 
  "The window (in seconds) over which typing speed should be evaluated." 
  :group 'typing-speed)

(defcustom typing-speed-mode-text-format " [%s WPM]" 
  "A format string that controls how the typing speed is displayed in the mode line. 
Must contain exactly one %s delimeter where the typing speed will be inserted." 
  :group 'typing-speed)

(defcustom typing-speed-update-interval 1 
  "How often the typing speed will update in the mode line, in seconds. 
It will always also update after every command." 
  :group 'typing-speed)

(defvar typing-speed-mode-text (format typing-speed-mode-text-format 0)) 
(defvar typing-speed-event-queue '()) 
(defvar typing-speed-update-timer nil)

(defun typing-speed-post-command-hook () 
  "When typing-speed-mode is enabled, fires after every command. If the 
command is self-insert-command, log it as a keystroke and update the 
typing speed." 
  (if (eq this-command 'self-insert-command) 
    (let ((current-time (float-time))) 
      (push current-time typing-speed-event-queue) 
      (typing-speed-update))))

(defun typing-speed-update () 
  "Calculate and display the typing speed." 
  (let ((current-time (float-time))) 
    (setq typing-speed-event-queue 
      (typing-speed-remove-old-events 
       (- current-time typing-speed-window) 
       typing-speed-event-queue)) 
    (typing-speed-message-update)))

(defun typing-speed-message-update () 
  "Updates the status bar with the current typing speed" 
  (let* ((chars-per-second (/ (length typing-speed-event-queue) (float typing-speed-window))) 
     (chars-per-min (* chars-per-second 60)) 
     (words-per-min (/ chars-per-min 5))) 
    (setq typing-speed-mode-text (format " [%s WPM]" (floor words-per-min))) 
    (force-mode-line-update)))

(defun typing-speed-remove-old-events (threshold queue) 
  "Removes events older than than the threshold (in seconds) from the specified queue" 
  (if (or (null queue) 
      (> threshold (car queue))) 
      nil 
      (cons (car queue) 
        (typing-speed-remove-old-events threshold (cdr queue)))))

(defun turn-on-typing-speed () 
  "Turns on typing-speed-mode" 
  (if (not typing-speed-mode) 
      (typing-speed-mode)))

(defun turn-off-typing-speed () 
  "Turns off typing-speed-mode" 
  (if typing-speed-mode 
      (typing-speed-mode)))