From c56a769fef3555a739011e5de4488818bf0d8a1a Mon Sep 17 00:00:00 2001
From: Doug Coleman <doug.coleman@gmail.com>
Date: Sun, 17 Aug 2008 12:01:04 -0500
Subject: [PATCH] add if-at, when-at, and unless-at it's like if-empty
---
extra/assocs/lib/lib.factor | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/extra/assocs/lib/lib.factor b/extra/assocs/lib/lib.factor
index 5036a13d78..5f4620fd64 100755
--- a/extra/assocs/lib/lib.factor
+++ b/extra/assocs/lib/lib.factor
@@ -37,3 +37,10 @@ IN: assocs.lib
H{ } clone [
swap [ change-at ] 2curry assoc-each
] keep ; inline
+
+: if-at ( obj assoc quot1 quot2 -- )
+ [ dupd at* [ not -rot ? ] keep ] 2dip if ; inline
+
+: when-at ( obj assoc quot -- ) [ ] if-at ; inline
+
+: unless-at ( obj assoc quot -- ) [ ] swap if-at ; inline