[functional-tests] fluid-let

2017-08-23 11:10:53 +01:00 · 2017-08-23 11:10:53 +01:00 · bc765ce89d
commit bc765ce89d
parent 2fe464a4cf
1 changed files with 14 additions and 1 deletions
--- a/functional-tests/utils.scm
+++ b/functional-tests/utils.scm
@ -2,7 +2,8 @@
  (utils)
  (export inc!
          dec!
-          swap!)
+          swap!
+          fluid-let)
  (import (rnrs))

  (define-syntax inc!
@ -21,4 +22,16 @@
       (let ((tmp x))
        (set! x y)
        (set! y tmp)))))
+
+  (define-syntax fluid-let
+    (syntax-rules ()
+      ((_ ((x e)) b1 b2 ...)
+       (let ((y e))
+        (let ((swap (lambda ()
+                      (let ((t x))
+                       (set! x y)
+                       (set! y t)))))
+          (dynamic-wind swap (lambda ()
+                               b1 b2 ...)
+                        swap))))))
  )