+; Rational primitives
+
+(define (numerator x)
+ (if (ratnum? x)
+ (rat:numerator x)
+ x))
+
+(define (denominator x)
+ (if (ratnum? x)
+ (rat:denominator x)
+ (if (fixnum? x)
+ 1
+ 1.0)))
+
+(define (rat:+ x y)
+ (make-rational (fix:+ (fix:* (numerator x) (denominator y))
+ (fix:* (denominator x) (numerator y)))
+ (fix:* (denominator x) (denominator y))))
+
+(define (rat:- x y)
+ (make-rational (fix:- (fix:* (numerator x) (denominator y))
+ (fix:* (denominator x) (numerator y)))
+ (fix:* (denominator x) (denominator y))))
+
+(define (rat:* x y)
+ (make-rational (fix:* (numerator x) (numerator y))
+ (fix:* (denominator x) (denominator y))))
+
+(define (rat:/ x y)
+ (make-rational (fix:* (numerator x) (denominator y))
+ (fix:* (denominator x) (numerator y))))
+
+(define (rat:1/ x)
+ (make-rational (denominator x) (numerator x)))
+