BusFactor1Inc

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; nock.lisp - The Interpretation and Compilation of Nock Programs.
;;
;; Nock is the Maxwell's Equations of Software. It is a language that
;; powers the Urbit virtual machine; its specification can fit on a 
;; t-shirt[1].  
;;
;; In this set of Common Lisp functions below are 'tar', 
;; a Nock interpreter, 'dao', a Nock compiler and 'phi',
;; a Nock compiler driver.

BusFactor1Inc

;; A nock interpreter
(defun tar (a f)
  (labels ((fas (b a)
	     (declare (integer b))
	     (cond
               ((= b 1) a)
               ((= b 2) (car a))
               ((= b 3) (cdr a))
               ((evenp b) (car (fas (/ b 2) a)))
               ((oddp b) (cdr (fas (/ (1- (the integer b)) 2) a))))))