From 78486f0d80e7c9b9adb18679f5506cbf6ec9519f Mon Sep 17 00:00:00 2001
From: Joe Groff <arcata@gmail.com>
Date: Fri, 5 Feb 2010 14:09:43 -0800
Subject: [PATCH] json: if-json-null combinator, in the same vein as if-zero,
 if-empty, etc.

---
 basis/json/json.factor | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/basis/json/json.factor b/basis/json/json.factor
index d7cfc0e5bc..790e85d610 100644
--- a/basis/json/json.factor
+++ b/basis/json/json.factor
@@ -1,7 +1,15 @@
+USING: kernel vocabs.loader ;
 IN: json
-USE: vocabs.loader
 
 SINGLETON: json-null
 
+: if-json-null ( x if-null else -- )
+    [ dup json-null? ]
+    [ [ drop ] prepose ]
+    [ ] tri* if ; inline
+
+: when-json-null ( x if-null -- ) [ ] if-json-null ; inline
+: unless-json-null ( x else -- ) [ ] swap if-json-null ; inline
+
 "json.reader" require
 "json.writer" require