diff --git a/extra/peg/ebnf/ebnf-tests.factor b/extra/peg/ebnf/ebnf-tests.factor
index 7aa61e84da..cf16fad2cd 100644
--- a/extra/peg/ebnf/ebnf-tests.factor
+++ b/extra/peg/ebnf/ebnf-tests.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2007 Chris Double.
 ! See http://factorcode.org/license.txt for BSD license.
 !
-USING: kernel tools.test peg peg.ebnf words ;
+USING: kernel tools.test peg peg.ebnf words math math.parser ;
 IN: peg.ebnf.tests
 
 { T{ ebnf-non-terminal f "abc" } } [
@@ -160,6 +160,13 @@ IN: peg.ebnf.tests
   "1-1" [EBNF foo='1' '+' '1' => [[ drop "foo" ]] | '1' '-' '1' => [[ drop "bar" ]] EBNF] call parse-result-ast
 ] unit-test
 
+{ 6 } [
+  "4+2" [EBNF num=[0-9] => [[ digit> ]] foo=num:x '+' num:y => [[ drop x y + ]] EBNF] call parse-result-ast
+] unit-test
+
+{ 6 } [
+  "4+2" [EBNF foo=[0-9]:x '+' [0-9]:y => [[ drop x digit> y digit> + ]] EBNF] call parse-result-ast
+] unit-test
 
 { V{ V{ 49 } "+" V{ 49 } } } [ 
   #! Test direct left recursion. 
diff --git a/extra/peg/ebnf/ebnf.factor b/extra/peg/ebnf/ebnf.factor
index f98b08093a..74b3e3540d 100644
--- a/extra/peg/ebnf/ebnf.factor
+++ b/extra/peg/ebnf/ebnf.factor
@@ -283,7 +283,7 @@ M: ebnf-optional (transform) ( ast -- parser )
     drop
   ] [
     [
-      "[let* | " %
+      "USING: locals namespaces ;  [let* | " %
       [ dup % " [ \"" % % "\" get ] " % ] each
       " | " %
       %