Rudimentary stepper.

Author: dvanhorn

langs/a86/stepper.rkt

@@ -0,0 +1,42 @@
+#lang racket
+(provide main)
+
+(require redex)
+
+(define-language L)
+
+;; A reduction relation that just relates elements
+;; of the list to their successors
+(define (r ls)
+  (define i 0)
+  (reduction-relation L
+                      (--> any_i
+                           any_j
+                           (where any_j
+                                  ,(begin
+                                     (set! i (add1 i))
+                                     (list-ref ls (min i (sub1 (length ls)))))))))
+
+
+;; reads log file from stdin
+(define (main)
+  (define ls
+    (let loop ()
+      (if (eof-object? (read))
+          '()
+          (cons (read) (loop)))))
+  
+  ;; replace instr indices with their instructions
+  (define ls1
+    (map (λ (s)
+           (map (λ (p)
+                  (match p
+                    [(list 'instr i)
+                     (list 'instr (list-ref (list-ref ls 0)
+                                            (add1 i)))]
+                    [_ p]))
+                s))
+         ls))
+
+  ;; run the stepper
+  (stepper (r (rest ls1)) (first (rest ls1))))