diff --git a/collects/parser-tools/lex.ss b/collects/parser-tools/lex.ss
index d404077..b0a1386 100644
--- a/collects/parser-tools/lex.ss
+++ b/collects/parser-tools/lex.ss
@@ -12,7 +12,7 @@
 
   (provide lexer lexer-src-pos define-lex-abbrev define-lex-abbrevs
 	   position-offset position-line position-col position?
-           define-tokens define-empty-tokens token-name token-value file-path)
+           define-tokens define-empty-tokens token-name token-value token? file-path)
   
   (define file-path (make-parameter #f))