Implement SQRT function

[jscl.git] / src / numbers.lisp

diff --git a/src/numbers.lisp b/src/numbers.lisp
index 18d679c..a386972 100644 (file)
--- a/src/numbers.lisp
+++ b/src/numbers.lisp
@@ -13,35 +13,34 @@
 ;; You should have received a copy of the GNU General Public License
 ;; along with JSCL.  If not, see <http://www.gnu.org/licenses/>.
 
-;;;; Various numeric functions and constants
+(/debug "loading numbers.lisp!")
 
-;; TODO: Use MACROLET when it exists
-(defmacro define-variadic-op (operator initial-value)
-  (let ((init-sym   (gensym))
-        (dolist-sym (gensym)))
-    `(defun ,operator (&rest args)
-       (let ((,init-sym ,initial-value))
-         (dolist (,dolist-sym args)
-           (setq ,init-sym (,operator ,init-sym ,dolist-sym)))
-         ,init-sym))))
+;;;; Various numeric functions and constants
 
-(define-variadic-op + 0)
-(define-variadic-op * 1)
+(macrolet ((def (operator initial-value)
+             (let ((init-sym   (gensym))
+                   (dolist-sym (gensym)))
+               `(defun ,operator (&rest args)
+                  (let ((,init-sym ,initial-value))
+                    (dolist (,dolist-sym args)
+                      (setq ,init-sym (,operator ,init-sym ,dolist-sym)))
+                    ,init-sym)))))
+  (def + 0)
+  (def * 1))
 
 ;; - and / work differently from the above macro.
 ;; If only one arg is given, it negates it or takes its reciprocal.
 ;; Otherwise all the other args are subtracted from or divided by it.
-;; TODO: Use MACROLET when it exists
-(defmacro define-sub-or-div (operator unary-form)
-  `(defun ,operator (x &rest args)
-     (cond
-       ((null args) ,unary-form)
-       (t (dolist (y args)
-            (setq x (,operator x y)))
-          x))))
-
-(define-sub-or-div - (-   x))
-(define-sub-or-div / (/ 1 x))
+(macrolet ((def (operator unary-form)
+             `(defun ,operator (x &rest args)
+                (cond
+                  ((null args) ,unary-form)
+                  (t (dolist (y args)
+                       (setq x (,operator x y)))
+                     x)))))
+  (def - (-   x))
+  (def / (/ 1 x)))
+
 
 (defun 1+ (x) (+ x 1))
 (defun 1- (x) (- x 1))
@@ -59,35 +58,70 @@
 (defun zerop (x) (= x 0))
 (defun plusp (x) (< 0 x))
 
-;; TODO: Use MACROLET when it exists
-(defmacro defcomparison (operator)
-  `(defun ,operator (x &rest args)
-     (dolist (y args) 
-       (if (,operator x y)
-         (setq x    (car args))
-         (return-from ,operator nil)))
-     t))
-
-(defcomparison >)
-(defcomparison >=)
-(defcomparison =) 
-(defcomparison <)
-(defcomparison <=)
-(defcomparison /=)
+(defun signum (x)
+  (if (zerop x) x (/ x (abs x))))
+
+(macrolet ((def (operator)
+             `(defun ,operator (x &rest args)
+                (dolist (y args) 
+                  (if (,operator x y)
+                      (setq x    (car args))
+                      (return-from ,operator nil)))
+                t)))
+  (def >)
+  (def >=)
+  (def =) 
+  (def <)
+  (def <=)
+  (def /=))
 
 (defconstant pi 3.141592653589793) 
 
 (defun evenp (x) (= (mod x 2) 0))
 (defun oddp  (x) (not (evenp x)))
 
-(flet ((%max-min (x xs func)
-         (dolist (y xs) 
-           (setq x  (if (funcall func x (car xs)) x y)))
-         x))
-  (defun max (x &rest xs) (%max-min x xs #'>))
-  (defun min (x &rest xs) (%max-min x xs #'<))) 
+(macrolet ((def (name comparison)
+             `(defun ,name (x &rest xs)
+                (dolist (y xs) 
+                  (when (,comparison y x)
+                    (setq x y)))
+                x)))
+  (def max >)
+  (def min <))
 
 (defun abs (x) (if (> x 0) x (- x)))
 
 (defun expt (base power) (expt base              power))
 (defun exp  (power)      (expt 2.718281828459045 power))
+
+(defun sqrt (x) (sqrt x))
+
+(defun gcd-2 (a b)
+  (if (zerop b)
+      (abs a)
+    (gcd-2 b (mod a b))))
+
+(defun gcd (&rest integers)
+  (cond ((null integers)
+        0)
+       ((null (cdr integers))
+        (abs (first integers)))
+       ((null (cddr integers))
+        (gcd-2 (first integers) (second integers)))
+       (t
+        (apply #'gcd (gcd (first integers) (second integers)) (nthcdr 2 integers)))))
+
+(defun lcm-2 (a b)
+  (if (or (zerop a) (zerop b))
+      0
+    (/ (abs (* a b)) (gcd a b))))
+
+(defun lcm (&rest integers)
+  (cond ((null integers)
+        1)
+       ((null (cdr integers))
+        (abs (first integers)))
+       ((null (cddr integers))
+        (lcm-2 (first integers) (second integers)))
+       (t
+        (apply #'lcm (lcm (first integers) (second integers)) (nthcdr 2 integers)))))