Added some port and string primitives.

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

diff --git a/src/scheme-library.scm b/src/scheme-library.scm
index f8c0ec4..14aa6f8 100644 (file)
--- a/src/scheme-library.scm
+++ b/src/scheme-library.scm
@@ -17,6 +17,41 @@
 
 ;; 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)
@@ -168,7 +203,7 @@
   (define (iter a count)
     (if (null? a)
       count
-      (iter (cdr a) (+ count 1))))
+      (iter (cdr a) (fix:+ count 1))))
   (iter l 0))
 
 ; Join two lists together
@@ -295,15 +330,42 @@
 (define (sum n)
 
   (define (sum-iter total count maxcount)
-    (if (> count maxcount)
+    (if (fix:> count maxcount)
       total
-      (sum-iter (+ total count) (+ count 1) maxcount)))
+      (sum-iter (fix:+ total count) (fix:+ count 1) maxcount)))
   
   (sum-iter 0 1 n))
 
 ; Recursive summation. Use this to compare with tail call
 ; optimized iterative algorithm.
 (define (sum-recurse n)
-  (if (= n 0)
+  (if (fix:= n 0)
     0
-    (+ n (sum-recurse (- n 1)))))
+    (fix:+ n (sum-recurse (fix:- n 1)))))
+
+;; MISC
+
+(define (license)
+  (display
+"This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see http://www.gnu.org/licenses/.
+"))
+
+(define (welcome)
+  (display
+"Welcome to scheme.forth.jl!
+
+Copyright (C) 2016 Tim Vaughan.
+This program comes with ABSOLUTELY NO WARRANTY; for details type '(license)'.
+Use Ctrl-D to exit.
+"))