1 files changed, 48 insertions, 23 deletions

diff --git a/src/yuescript/yue_parser.cpp b/src/yuescript/yue_parser.cpp
index f215ee4..99fea0a 100644
--- a/src/yuescript/yue_parser.cpp
+++ b/src/yuescript/yue_parser.cpp
@@ -93,6 +93,11 @@ YueParser::YueParser() {
                 return false;
         });
 
+        export_expression_error = pl::user(true_(), [](const item_t& item) {
+                throw ParserError("invalid export expression"sv, item.begin);
+                return false;
+        });
+
         #define ensure(patt, finally) ((patt) >> (finally) | (finally) >> cut)
 
         #define key(str) (expr(str) >> not_alpha_num)
@@ -666,29 +671,48 @@ YueParser::YueParser() {
                 State* st = reinterpret_cast<State*>(item.user_data);
                 st->exportCount++;
                 return true;
-        }) >> (pl::user(space >> ExportDefault >> space >> Exp, [](const item_t& item) {
-                State* st = reinterpret_cast<State*>(item.user_data);
-                if (st->exportDefault) {
-                        throw ParserError("export default has already been declared"sv, item.begin);
-                }
-                if (st->exportCount > 1) {
-                        throw ParserError("there are items already being exported"sv, item.begin);
-                }
-                st->exportDefault = true;
-                return true;
-        })
-        | (not_(space >> ExportDefault) >> pl::user(true_(), [](const item_t& item) {
-                State* st = reinterpret_cast<State*>(item.user_data);
-                if (st->exportDefault && st->exportCount > 1) {
-                        throw ParserError("can not export any more items when 'export default' is declared"sv, item.begin);
-                }
-                return true;
-        }) >> space >> ExpList >> -(space >> Assign))
-        | space >> pl::user(Macro, [](const item_t& item) {
-                State* st = reinterpret_cast<State*>(item.user_data);
-                st->exportMacro = true;
-                return true;
-        })) >> not_(space >> StatementAppendix);
+        }) >> (
+                pl::user(space >> ExportDefault >> space >> Exp, [](const item_t& item) {
+                        State* st = reinterpret_cast<State*>(item.user_data);
+                        if (st->exportDefault) {
+                                throw ParserError("export default has already been declared"sv, item.begin);
+                        }
+                        if (st->exportCount > 1) {
+                                throw ParserError("there are items already being exported"sv, item.begin);
+                        }
+                        st->exportDefault = true;
+                        return true;
+                }) |
+                not_(space >> ExportDefault) >> pl::user(true_(), [](const item_t& item) {
+                        State* st = reinterpret_cast<State*>(item.user_data);
+                        if (st->exportDefault && st->exportCount > 1) {
+                                throw ParserError("can not export any more items when 'export default' is declared"sv, item.begin);
+                        }
+                        return true;
+                }) >> (
+                        and_(set(".[")) >> ((pl::user(and_('.' >> Metatable), [](const item_t& item) {
+                                State* st = reinterpret_cast<State*>(item.user_data);
+                                if (st->exportMetatable) {
+                                        throw ParserError("module metatable duplicated"sv, item.begin);
+                                }
+                                if (st->exportMetamethod) {
+                                        throw ParserError("metatable should be exported before metamethod"sv, item.begin);
+                                }
+                                st->exportMetatable = true;
+                                return true;
+                        }) | pl::user(and_(".<"), [](const item_t& item) {
+                                State* st = reinterpret_cast<State*>(item.user_data);
+                                st->exportMetamethod = true;
+                                return true;
+                        }) | true_()) >> (DotChainItem | index) >> space >> Assign | export_expression_error) |
+                        space >> ExpList >> -(space >> Assign)
+                ) |
+                space >> pl::user(Macro, [](const item_t& item) {
+                        State* st = reinterpret_cast<State*>(item.user_data);
+                        st->exportMacro = true;
+                        return true;
+                })
+        ) >> not_(space >> StatementAppendix);
 
         VariablePair = ':' >> Variable;
 
@@ -897,6 +921,7 @@ ParseInfo YueParser::parse(std::string_view codes, rule& r) {
                         res.moduleName = std::move(state.moduleName);
                         res.exportDefault = state.exportDefault;
                         res.exportMacro = state.exportMacro;
+                        res.exportMetatable = !state.exportMetatable && state.exportMetamethod;
                 }
         } catch (const ParserError& err) {
                 res.error = {err.what(), err.line, err.col};