Gacela as Guile modules.

[gacela.git] / src / gacela_misc.scm

diff --git a/src/gacela_misc.scm b/src/gacela_misc.scm
index 42c8841f7e0bf132848a09eab5a5b315b1f91a58..8e8db1341bbbecda9e4ea149eabe475a50db2f28 100644 (file)
--- a/src/gacela_misc.scm
+++ b/src/gacela_misc.scm
@@ -21,6 +21,33 @@
 (use-modules (srfi srfi-1))
 
 
+;;; Constants
+
+(define *pi* (* (asin 1) 2))
+
+
+;;; Geometry
+
+(define (degrees-to-radians angle)
+  (/ (* angle *pi*) 180))
+
+(define (radians-to-degrees angle)
+  (/ (* angle 180) *pi*))
+
+(define (distance-between-points p1 p2)
+  (define (add-power-of-two p1 p2)
+    (cond ((null? p1)
+          0)
+         (else
+          (+ (expt (- (car p1) (car p2)) 2)
+             (add-power-of-two (cdr p1) (cdr p2))))))
+
+  (cond ((not (= (length p1) (length p2)))
+        #f)
+       (else
+        (sqrt (add-power-of-two p1 p2)))))
+
+
 ;;; Functions
 
 (define (nearest-power-of-two n)
@@ -29,6 +56,15 @@
          (else (power (* p 2) n))))
   (power 1 n))
 
-(define-macro (pushnew elem list)
-  `(cond ((not (find (lambda (e) (eq? e ,elem)) ,list))
-         (set! ,list (cons ,elem ,list)))))
+;(define-macro (pushnew elem list)
+;  `(cond ((not (find (lambda (e) (eq? e ,elem)) ,list))
+;        (set! ,list (cons ,elem ,list)))))
+
+(define (assoc-multiple-set! alist . pairs)
+  (define (amset! alist pairs)
+    (cond ((< (length pairs) 2)
+          alist)
+         (else
+          (assoc-set! alist (car pairs) (cadr pairs))
+          (amset! alist (cddr pairs)))))
+  (amset! alist pairs))