Add (limited) multiplication to stdlib.

Author: dvanhorn

langs/outlaw/compile.rkt

@@ -70,6 +70,7 @@
          system-type ;; hard-coded
          not findf
          read-line
+         * ; limited
          exact->inexact / expt string->keyword ; unimplemented
          ;; Op0
          read-byte peek-byte void

langs/outlaw/stdlib.rkt

@@ -13,6 +13,7 @@
          not
          findf
          read-line
+         * ; limited
          char-alphabetic? char-whitespace?
          displayln ; only works for strings
          write-string
@@ -92,6 +93,21 @@
 (define (procedure? x) (%procedure? x))
 (define (eq-hash-code x) (%eq-hash-code x))
 
+(define (* x y)
+  (match x
+    [0 0]
+    [1 y]
+    [2  (arithmetic-shift y 1)]
+    [4  (arithmetic-shift y 2)]
+    [8  (arithmetic-shift y 3)]
+    [10 ; 10a=2^3a+2a
+     (+ (arithmetic-shift y 1)
+        (arithmetic-shift y 3))]
+    [16 (arithmetic-shift y 4)]
+    [64 (arithmetic-shift y 6)]
+    [_ (error "unimplemented multiplication")]))
+
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Op2
 (define (+ . xs)

langs/outlaw/test/test-runner.rkt

@@ -668,7 +668,16 @@
                 #f)
   (check-equal? (run '(apply string-append (list "x")))
                 "x")
-  )
+
+  (check-equal? (run '(* 0 8)) 0)
+  (check-equal? (run '(* 1 8)) 8)
+  (check-equal? (run '(* 2 9)) 18)
+  (check-equal? (run '(* 2 -3)) -6)
+  (check-equal? (run '(* 4 3)) 12)
+  (check-equal? (run '(* 8 3)) 24)
+  (check-equal? (run '(* 16 2)) 32)
+  (check-equal? (run '(* 10 5)) 50)
+  (check-equal? (run '(* 64 2)) 128))
 
 
 (define (test-runner-io run)