diff -ur v6/ezyaml.py v7/ezyaml.py
--- v6/ezyaml.py	2018-08-31 22:53:33.000000000 +0900
+++ v7/ezyaml.py	2018-08-31 22:54:11.000000000 +0900
@@ -7,6 +7,8 @@
 	sys.exit(1)
 
 qts = ('"', "'")
+kwd_true = [ 'True', 'true', 'TRUE', 'ON', 'On', 'on' ]
+kwd_false = [ 'False', 'false', 'FALSE', 'OFF', 'Off', 'off' ]
 
 def parse(s):
 	lst = ['']
@@ -126,6 +128,12 @@
 	except ValueError:
 		pass
 
+	if s in kwd_true:
+		return True
+	if s in kwd_false:
+		return False
+	if s == 'null':
+		return None
 	if s == '[]':
 		return []
 	if s == '{}':
@@ -202,8 +210,7 @@
 	return '\n'.join(lines)
 
 def need_quote(s):
-	kwd = [ '', 'True', 'true', 'TRUE', 'False', 'false', 'FALSE', 'ON', 'On', 'on', 'OFF', 'Off', 'off' ]
-	if s in kwd:
+	if s in [''] + kwd_true + kwd_false:
 		return True
 
 	hts = [ ('[', ']'), ('{', '}') ]