Primitive ratnum operations implemented.

[scheme.forth.jl.git] / src / scheme-library.scm

diff --git a/src/scheme-library.scm b/src/scheme-library.scm
index fc3c9b9..85580fd 100644 (file)
--- a/src/scheme-library.scm
+++ b/src/scheme-library.scm
@@ -17,8 +17,65 @@
 
 ;; NUMBERS
 
+; 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)))
+
+; Type dispatch and promotion
+
+(define (type-dispatch ops x)
+  (if (flonum? x)
+    ((cdr ops) x)
+    ((car ops) x)))
+
+(define (promote-dispatch ops x y)
+  (if (flonum? x)
+    (if (flonum? y)
+      ((cdr ops) x y)
+      ((cdr ops) x (fixnum->flonum y)))
+    (if (flonum? y)
+      ((cdr ops) (fixnum->flonum x) y)
+      ((car ops) x y))))
+
 ; Unary ops
 
+(define (neg x)
+  (type-dispatch (cons fix:neg flo:neg) x))
+
+(define (abs x)
+  (type-dispatch (cons fix:abs flo:abs) x))
+
 (define (flo:1+ x) (flo:+ x 1.0))
 (define (flo:1- x) (flo:- x 1.0))
 
@@ -40,31 +97,17 @@
 (define (truncate x)
   (apply-to-flonum flo:truncate x))
 
-; Type dispatch and promotion
-
-(define (type-dispatch ops x)
-  (if (flonum? x)
-    ((cdr ops) x)
-    ((car ops) x)))
-
-(define (promote-dispatch ops x y)
-  (if (flonum? x)
-    (if (flonum? y)
-      ((cdr ops) x y)
-      ((cdr ops) x (fixnum->flonum y)))
-    (if (flonum? y)
-      ((cdr ops) (fixnum->flonum x) y)
-      ((car ops) x y))))
-
 ; Binary operations
 
+(define (fix:/ x y) ; Non-standard definition while we don't have rationals
+  (if (fix:= 0 (fix:remainder x y))
+    (fix:quotient x y)
+    (flo:/ (fixnum->flonum x) (fixnum->flonum y))))
+
 (define (pair+ x y) (promote-dispatch (cons fix:+ flo:+) x y))
 (define (pair- x y) (promote-dispatch (cons fix:- flo:-) x y))
 (define (pair* x y) (promote-dispatch (cons fix:* flo:*) x y))
-(define (pair/ x y) (promote-dispatch
-                      (cons (lambda 'args
-                              (error "Division unsupported for integers."))
-                            flo:/) x y))
+(define (pair/ x y) (promote-dispatch (cons fix:/ flo:/) x y))
 
 (define (pair> x y) (promote-dispatch (cons fix:> flo:>) x y))
 (define (pair< x y) (promote-dispatch (cons fix:< flo:<) x y))
@@ -72,9 +115,6 @@
 (define (pair<= x y) (promote-dispatch (cons fix:<= flo:<=) x y))
 (define (pair= x y) (promote-dispatch (cons fix:= flo:=) x y))
 
-(define (neg x)
-  (type-dispatch (cons fix:neg flo:neg) x))
-
 (define (null? arg)
   (eq? arg '()))