diff --git a/piclib/built-in.scm b/piclib/built-in.scm
index f884c106..6f6ee163 100644
--- a/piclib/built-in.scm
+++ b/piclib/built-in.scm
@@ -600,10 +600,23 @@
       (identifier=? use-env x use-env y))
     (make-syntactic-closure use-env '() (f expr rename compare))))
 
+(define (acons key val alist)
+  (cons (cons key val) alist))
+
 (define (ir-macro-transformer f)
   (lambda (expr use-env mac-env)
-    (define (inject identifier)
-      (make-syntactic-closure use-env '() identifier))
-    (define (compare x y)
-      (identifier=? use-env x use-env y))
-    (make-syntactic-closure mac-env '() (f (walk inject expr) inject compare))))
+    (let ((wrapped '()))
+      (define (inject obj)
+	(let ((s (make-syntactic-closure use-env '() obj)))
+	  (set! wrapped (acons s obj wrapped))
+	  s))
+      (define (extract obj)
+	(let ((t (assq obj wrapped)))
+	  (if t (cdr t) obj)))
+      (define (wrap expr)
+	(walk inject expr))
+      (define (unwrap expr)
+	(walk extract expr))
+      (define (compare x y)
+	(identifier=? use-env x use-env y))
+      (make-syntactic-closure mac-env '() (unwrap (f (wrap expr) inject compare))))))