From c7500a09908b4463f5c29c17afc7a17a118ff2b2 Mon Sep 17 00:00:00 2001
From: James Cash <james.nvc@gmail.com>
Date: Wed, 14 May 2008 20:46:22 -0400
Subject: [PATCH] error checks for look up an undefined function

---
 extra/lisp/lisp.factor | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/extra/lisp/lisp.factor b/extra/lisp/lisp.factor
index 8582021d6d..3e4cdca41f 100644
--- a/extra/lisp/lisp.factor
+++ b/extra/lisp/lisp.factor
@@ -76,6 +76,7 @@ PRIVATE>
 ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
 SYMBOL: lisp-env
+ERROR: no-such-var var ;
 
 : init-env ( -- )
   H{ } clone lisp-env set ;
@@ -84,7 +85,7 @@ SYMBOL: lisp-env
   swap lisp-env get set-at ;
   
 : lisp-get ( name -- word )
-  lisp-env get at ;
+  dup lisp-env get at [ ] [ no-such-var ] ?if ;
   
 : funcall ( quot sym -- * )
   dup lisp-symbol?  [ name>> lisp-get ] when call ; inline
\ No newline at end of file