add syntax/strip-context

svn: r13846

collects/syntax/strip-context.ss

@@ -0,0 +1,20 @@
+#lang scheme/base
+
+(define (strip-context e)
+  (cond
+   [(syntax? e)
+    (datum->syntax #f
+                   (strip-context (syntax-e e))
+                   e
+                   e)]
+   [(pair? e) (cons (strip-context (car e))
+                    (strip-context (cdr e)))]
+   [(vector? e) (list->vector
+                 (map strip-context
+                      (vector->list e)))]
+   [(box? e) (box (strip-context (unbox e)))]
+   [(prefab-struct-key e)
+    => (lambda (k)
+         (apply make-prefab-struct
+                (strip-context (cdr (vector->list (struct->vector e))))))]
+   [else e]))