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commit fc798ea1666c7d14db6c14b150ae480338bd4a1a
parent 3b5732fb6ea24216ec83cd8bba3add7788bc141a
Author: Ryan Culpepper <ryanc@racket-lang.org>
Date:   Sat, 10 Feb 2007 03:46:12 +0000

Macro stepper: factored derivation synthesis code into separate module

svn: r5585

original commit: 204516bad91acb472c33eb872fa1c496a10a2c14

Diffstat:
M
collects/macro-debugger/model/stx-util.ss
 | 
9
+++++----

1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/collects/macro-debugger/model/stx-util.ss b/collects/macro-debugger/model/stx-util.ss
@@ -64,9 +64,10 @@
     (cond [(zero? n) null]
           [else (cons (stx-car items) (stx-take (stx-cdr items) (sub1 n)))]))
 
+  ;; stx-improper-length : syntax -> number
   (define (stx-improper-length stx)
-    (if (stx-pair? stx)
-        (add1 (stx-improper-length (stx-cdr stx)))
-        0))
-
+    (let loop ([stx stx] [n 0])
+      (if (stx-pair? stx)
+          (loop (stx-cdr stx) (add1 n))
+          n)))
   )