diff --git a/extra/peg/peg.factor b/extra/peg/peg.factor
index 7fa1fb90e5..411a47b9bd 100644
--- a/extra/peg/peg.factor
+++ b/extra/peg/peg.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2007 Chris Double.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: kernel sequences strings namespaces math assocs shuffle 
-       vectors arrays combinators.lib memoize ;
+       vectors arrays combinators.lib memoize math.parser ;
 IN: peg
 
 TUPLE: parse-result remaining ast ;
@@ -265,3 +265,16 @@ MEMO: delay ( parser -- parser )
 
 MEMO: list-of ( items separator -- parser )
   hide over 2array seq repeat0 [ concat ] action 2array seq [ unclip 1vector swap first append ] action ;
+
+MEMO: 'digit' ( -- parser )
+  [ digit? ] satisfy [ digit> ] action ;
+
+MEMO: 'integer' ( -- parser )
+  'digit' repeat1 [ 10 swap digits>integer ] action ;
+
+MEMO: 'string' ( -- parser )
+  [
+    [ CHAR: " = ] satisfy hide ,
+    [ CHAR: " = not ] satisfy repeat0 ,
+    [ CHAR: " = ] satisfy hide ,
+  ] { } make seq [ first >string ] action ;