--- esa.py-	2016-09-11 23:00:00.000000000 +0900
+++ esa.py	2016-09-12 00:00:00.000000000 +0900
@@ -444,7 +444,10 @@ def do_kwd(v, expr, info):
 			do_expr( expr[3], info )
 		return None
 	if v == 'for':
-		args = expr[2][2][::2]
+		args = expr[2][2]
+		is_omit = lambda lst, i: len(lst) <= i or lst[i] == [ 'etc', ';' ]
+		f = lambda lst, i: lst[:i] + [ [ 'num', '1' ] ] + lst[i:] if is_omit(lst, i) else lst
+		args = reduce( f, [ 0, 2, 4 ], args )[::2]
 		do_expr( args[0], info )
 		while do_expr( args[1], info ):
 			do_expr( expr[3], info )