From 6253d8632c319a3ca7acf1c7c3cb1cc886660273 Mon Sep 17 00:00:00 2001
From: Scott Owens <sowens@cs.utah.edu>
Date: Wed, 8 Feb 2006 16:39:29 +0000
Subject: [PATCH] Fix bug in set difference.

svn: r2170

original commit: 5fe7041f17cf06a26e9d49e2cf5e6d0a281e7bfd
---
 collects/parser-tools/lex-sre.ss | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/collects/parser-tools/lex-sre.ss b/collects/parser-tools/lex-sre.ss
index 6c8d777..9c6a6a7 100644
--- a/collects/parser-tools/lex-sre.ss
+++ b/collects/parser-tools/lex-sre.ss
@@ -73,7 +73,7 @@
       ((_ re ...)
        (char-complement (union re ...)))))
   
-  ;; char-set difference
+  ;; set difference
   (define-lex-trans (sre-- stx)
     (syntax-case stx ()
       ((_)
@@ -81,7 +81,7 @@
                            "must have at least one argument"
                            stx))
       ((_ big-re re ...)
-       (syntax (intersect big-re (~ (union re) ...))))))
+       (syntax (& big-re (complement (union re ...)))))))
   
   (define-lex-trans (sre-/ stx)
     (syntax-case stx ()