1 files changed, 4 insertions, 3 deletions

diff --git a/src/yuescript/yue_parser.cpp b/src/yuescript/yue_parser.cpp
index 6ecd369..5628062 100755
--- a/src/yuescript/yue_parser.cpp
+++ b/src/yuescript/yue_parser.cpp
@@ -323,7 +323,8 @@ YueParser::YueParser() {
                 expr("&") |
                 expr("|") |
                 expr(">>") |
-                expr("<<");
+                expr("<<") |
+                expr("??");
 
         Update = Space >> update_op >> expr("=") >> Exp;
 
@@ -360,7 +361,7 @@ YueParser::YueParser() {
                 expr("//") |
                 set("+-*/%><|&~");
         exp_op_value = Space >> BinaryOperator >> *SpaceBreak >> pipe_exp;
-        Exp = Seperator >> pipe_exp >> *exp_op_value;
+        Exp = Seperator >> pipe_exp >> *exp_op_value >> -(Space >> expr("??") >> Exp);
 
         DisableChain = pl::user(true_(), [](const item_t& item) {
                 State* st = reinterpret_cast<State*>(item.user_data);
@@ -424,7 +425,7 @@ YueParser::YueParser() {
         Metatable = expr('#');
         Metamethod = Name >> expr('#');
 
-        existential_op = expr('?');
+        existential_op = expr('?') >> not_(expr('?'));
         chain_call = (Callable | String) >> -existential_op >> ChainItems;
         chain_item = and_(set(".\\")) >> ChainItems;
         chain_dot_chain = DotChainItem >> -existential_op >> -ChainItems;