benchmark.json: adding a json benchmark.

extra/benchmark/json/json.factor

@@ -0,0 +1,11 @@
+! Copyright (C) 2012 John Benediktsson
+! See http://factorcode.org/license.txt for BSD license.
+USING: assocs json.reader json.writer kernel math math.parser
+sequences ;
+IN: benchmark.json
+
+: json-benchmark ( -- )
+    200 iota [ [ number>string ] keep ] H{ } map>assoc
+    1,000 [ >json json> ] times drop ;
+
+MAIN: json-benchmark