🚀 go-pugleaf

The following code will display an approximation of the US national debt
in the wholine.  This (rather large) number will be displayed in the 
file-state sheet when there are no open files, and it will update about
once a second.  Setting the variable *WHOLINE-DISPLAY-NATIONAL-DEBT*
to NIL will make it go away (just the number, not the debt).

	-- Jamie "Yow, am I socially conscious yet?" Zawinski


PS: I don't think it creates any garbage, since bignum consing happens
    on the PDL, and this code reuses the string that is drawn.

PPS: There is little chance of this working on a microexplorer.


;;; -*- Mode:Lisp Syntax:Common-Lisp; Package:USER; -*-

;;; File "NATIONAL-DEBT".
;;; Display a running total of the US national debt in the wholine.
;;; Inspired by a similar program for the Amiga by Ron Charlton.
;;; Numbers come from the Survey of Current Business, 1989.
;;;
;;;  9 Oct 89   Jamie Zawinski   Created.

(defconstant DEC-31-88-NATIONAL-DEBT 2707284000000
  "The US National Debt as of Dec 31, 1988.")

(defconstant DEC-31-88-NATIONAL-DEBT-DELTA 7673.015L0
  "The rate of increase of the US National Debt as of Dec 31, 1988 (in dollars per second).")

(defun national-debt-at (universal-time)
  (let* ((dec-31-88 #.(encode-universal-time 0 0 24 31 12 1988))
	 (seconds-since-then (- universal-time dec-31-88))
	 (delta-since-then (truncate (* DEC-31-88-NATIONAL-DEBT-DELTA
					seconds-since-then))))
    (+ DEC-31-88-NATIONAL-DEBT delta-since-then)))

(defvar *wholine-national-debt-string*
	(make-array 21 :element-type 'string-char :fill-pointer 0)
  "A string which is reused when computing the national debt.")

(defvar *wholine-display-national-debt* t
  "Whether the wholine file-state sheet should display the current US national debt when there is nothing else to show.")

(profile:define-profile-variable *wholine-display-national-debt* (:ucl)
  :cvv-type :boolean)

(defmethod (tv:who-line-file-sheet :after :update) ()
  "Display the national debt, if nothing else is there."
  (declare (optimize (speed 3)))  ; Turn on format-optimization.
  (when (and *wholine-display-national-debt*
	     (eq tv:who-line-item-state 'tv:null))
    (let ((string *wholine-national-debt-string*))
      (declare (string string))
      (setf (fill-pointer string) 1)
      (setf (schar string 0) #\$)
      (format string "~:D"
	      (the integer (national-debt-at (get-universal-time))))
      (send self :clear-screen)
      (send self :string-out-explicit string
            (- (tv:sheet-inside-width) (send self :string-length string))))))