diff --git a/extra/lisp/lisp.factor b/extra/lisp/lisp.factor
index e051241a32..3dba8cfb1d 100644
--- a/extra/lisp/lisp.factor
+++ b/extra/lisp/lisp.factor
@@ -1,8 +1,16 @@
 ! Copyright (C) 2008 James Cash
 ! See http://factorcode.org/license.txt for BSD license.
-USING: kernel peg.ebnf peg.expr ;
+USING: kernel peg.ebnf peg.expr math.parser sequences arrays ;
 IN: lisp
 
-EBNF: expr
-list  = "(" ( atom | list )* ")"   =>  [[ second 1array ]]
+EBNF: lisp-expr
+digit      = [0-9]                     => [[ digit> ]]
+integer    = (digit)+                  => [[ 10 digits>integer ]]
+float      = (digit)+ "." (digit)*     => [[ 3 head 3append string>number ]]
+number     = integer
+             | float
+identifier = [a-zA-Z] ([a-zA-Z0-9])*
+atom       = number
+             | identifier          
+list       = "(" (atom|list)* ")"      =>  [[ second 1array ]]
 ;EBNF
\ No newline at end of file
diff --git a/extra/lisp/tags.txt b/extra/lisp/tags.txt
index 0ca0d1aa8c..eee3fba9aa 100644
--- a/extra/lisp/tags.txt
+++ b/extra/lisp/tags.txt
@@ -1 +1 @@
-Lisp languages
+lisp