From ab56eb0e48b9e1f82b035ab43ff6bf491815eb98 Mon Sep 17 00:00:00 2001
From: Doug Coleman <doug.coleman@gmail.com>
Date: Sun, 17 Aug 2008 21:27:35 -0500
Subject: [PATCH] add ?at, simplify if-at

---
 extra/assocs/lib/lib.factor | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/extra/assocs/lib/lib.factor b/extra/assocs/lib/lib.factor
index 5f4620fd64..2a8634987f 100755
--- a/extra/assocs/lib/lib.factor
+++ b/extra/assocs/lib/lib.factor
@@ -38,8 +38,11 @@ IN: assocs.lib
         swap [ change-at ] 2curry assoc-each
     ] keep ; inline
 
+: ?at ( obj1 assoc -- obj1/obj2 )
+    dupd at* [ nip ] [ drop ] if ;
+
 : if-at ( obj assoc quot1 quot2 -- )
-    [ dupd at* [ not -rot ? ] keep ] 2dip if ; inline
+    [ ?at dup ] 2dip if ; inline
 
 : when-at ( obj assoc quot -- ) [ ] if-at ; inline