Function: math-decompose-units

math-decompose-units is a byte-compiled function defined in calc-units.el.gz.

Signature

(math-decompose-units UNITS)

Source Code

;; Defined in /usr/src/emacs/lisp/calc/calc-units.el.gz
(defun math-decompose-units (units)
  (let ((u (math-check-unit-name units)))
    (and u (eq (car-safe (nth 1 u)) '+)
	 (setq units (nth 1 u))))
  (setq units (calcFunc-expand units))
  (and (eq (car-safe units) '+)
       (let ((entry (list units calc-internal-prec calc-prefer-frac)))
	 (or (equal entry (car math-decompose-units-cache))
	     (let ((ulist nil)
		   (utemp units))
	       (while (eq (car-safe utemp) '+)
		 (setq ulist (cons (math-decompose-unit-part (nth 2 utemp))
				   ulist)
		       utemp (nth 1 utemp)))
	       (setq ulist (cons (math-decompose-unit-part utemp) ulist)
		     utemp ulist)
	       (while (setq utemp (cdr utemp))
		 (unless (equal (nth 2 (car utemp)) (nth 2 (car ulist)))
		   (error "Inconsistent units in sum")))
	       (setq math-decompose-units-cache
		     (cons entry
			   (sort ulist
                                 (lambda (x y)
                                   (not (Math-lessp (nth 1 x)
                                                    (nth 1 y)))))))))
	 (cdr math-decompose-units-cache))))