--- es_i.py-	2016-10-06 00:00:00.000000000 +0900
+++ es_i.py	2016-10-06 01:00:00.000000000 +0900
@@ -169,6 +169,12 @@ def tree_op2(lst, ops, e, k1, v1):
 		err_not_found("right term op='{}'".format(v1))
 	return [ op2( ops, e, k1, v1, r[0] ) ] + r[1:]
 
+def tree_op_fdef_arg(lst, ops):
+	if [ 'op', ',' ] not in lst:
+		return tree_op(lst, ops)
+	i = lst.index( [ 'op', ',' ] )
+	return tree_op( lst[:i], ops ) + [ lst[i] ] + tree_op_fdef_arg( lst[i+1:], ops )
+
 def tree_op(lst, ops):
 	tstk_push( [ 'op', lst ] )
 	if len(lst) == 0:
@@ -181,7 +187,7 @@ def tree_op(lst, ops):
 	elif k == 'fcall':
 		e = [ k, v, tree_op( [ e[2] ], ops )[0] ]
 	elif k == 'fdef':
-		e2 = e[2][:2] + [ tree_op( e[2][2], ops ) ]
+		e2 = e[2][:2] + [ tree_op_fdef_arg( e[2][2], ops ) ]
 		e = [ k, v, e2, e[3], tree_op( [ e[4] ], ops )[0] ]
 
 	if k == 'op':