6 files changed, 352 insertions, 160 deletions

diff --git a/src/yuescript/parser.cpp b/src/yuescript/parser.cpp
index 5939793..be38e83 100644
--- a/src/yuescript/parser.cpp
+++ b/src/yuescript/parser.cpp
@@ -608,7 +608,8 @@ public:
 
 protected:
         // left and right expressions
-        _expr *m_left, *m_right;
+        _expr* m_left;
+        _expr* m_right;
 };
 
 // sequence
@@ -632,6 +633,42 @@ public:
         }
 };
 
+// sequence list
+class _seq_list : public _expr {
+public:
+        // constructor.
+        _seq_list(std::initializer_list<expr> list) {
+                m_list.reserve(list.size());
+                for (const expr& expr : list) {
+                        m_list.push_back(_private::get_expr(expr));
+                }
+        }
+
+        virtual ~_seq_list() {
+                for (_expr* expr : m_list) {
+                        delete expr;
+                }
+        }
+
+        // parse with whitespace
+        virtual bool parse_non_term(_context& con) const {
+                for (_expr* expr : m_list) {
+                        if (!expr->parse_non_term(con)) return false;
+                }
+                return true;
+        }
+
+        // parse terminal
+        virtual bool parse_term(_context& con) const {
+                for (_expr* expr : m_list) {
+                        if (!expr->parse_term(con)) return false;
+                }
+                return true;
+        }
+private:
+        std::vector<_expr*> m_list;
+};
+
 // choice
 class _choice : public _binary {
 public:
@@ -657,6 +694,46 @@ public:
         }
 };
 
+// select
+class _sel : public _expr {
+public:
+        // constructor.
+        _sel(std::initializer_list<expr> list) {
+                m_list.reserve(list.size());
+                for (const expr& expr : list) {
+                        m_list.push_back(_private::get_expr(expr));
+                }
+        }
+
+        virtual ~_sel() {
+                for (_expr* expr : m_list) {
+                        delete expr;
+                }
+        }
+
+        // parse with whitespace
+        virtual bool parse_non_term(_context& con) const {
+                _state st(con);
+                for (_expr* expr : m_list) {
+                        if (expr->parse_non_term(con)) return true;
+                        if (expr != m_list.back()) con.restore(st);
+                }
+                return false;
+        }
+
+        // parse terminal
+        virtual bool parse_term(_context& con) const {
+                _state st(con);
+                for (_expr* expr : m_list) {
+                        if (expr->parse_term(con)) return true;
+                        if (expr != m_list.back()) con.restore(st);
+                }
+                return false;
+        }
+private:
+        std::vector<_expr*> m_list;
+};
+
 // reference to rule
 class _ref : public _expr {
 public:
@@ -1186,6 +1263,14 @@ expr operator>>(const expr& left, const expr& right) {
                 new _seq(_private::get_expr(left), _private::get_expr(right)));
 }
 
+/** creates a sequence of expressions.
+        @param list list of expressions.
+        @return an expression which parses a sequence.
+*/
+expr seq(std::initializer_list<expr> list) {
+        return _private::construct_expr(new _seq_list(list));
+}
+
 /** creates a choice of expressions.
         @param left left operand.
         @param right right operand.
@@ -1196,6 +1281,14 @@ expr operator|(const expr& left, const expr& right) {
                 new _choice(_private::get_expr(left), _private::get_expr(right)));
 }
 
+/** creates multiple choices of expressions.
+        @param list list of expressions.
+        @return an expression which parses multiple choices.
+*/
+expr sel(std::initializer_list<expr> list) {
+        return _private::construct_expr(new _sel(list));
+}
+
 /** converts a parser expression into a terminal.
         @param e expression.
         @return an expression which parses a terminal.
diff --git a/src/yuescript/parser.hpp b/src/yuescript/parser.hpp
index 7bec5d5..b504866 100644
--- a/src/yuescript/parser.hpp
+++ b/src/yuescript/parser.hpp
@@ -303,6 +303,12 @@ private:
 */
 expr operator>>(const expr& left, const expr& right);
 
+/** creates a sequence of expressions.
+        @param list list of expressions.
+        @return an expression which parses a sequence.
+*/
+expr seq(std::initializer_list<expr> list);
+
 /** creates a choice of expressions.
         @param left left operand.
         @param right right operand.
@@ -310,6 +316,12 @@ expr operator>>(const expr& left, const expr& right);
 */
 expr operator|(const expr& left, const expr& right);
 
+/** creates multiple choices of expressions.
+        @param list list of expressions.
+        @return an expression which parses multiple choices.
+*/
+expr sel(std::initializer_list<expr> list);
+
 /** converts a parser expression into a terminal.
         @param e expression.
         @return an expression which parses a terminal.
diff --git a/src/yuescript/yue_ast.h b/src/yuescript/yue_ast.h
index 86f1904..6a1a940 100644
--- a/src/yuescript/yue_ast.h
+++ b/src/yuescript/yue_ast.h
@@ -521,11 +521,12 @@ class unary_value_t;
 class FunLit_t;
 
 AST_NODE(SimpleValue)
-        ast_sel<true, const_value_t,
+        ast_sel<true,
+        TableLit_t, const_value_t,
         If_t, Switch_t, With_t, ClassDecl_t,
         ForEach_t, For_t, While_t, Do_t, Try_t,
         unary_value_t,
-        TblComprehension_t, TableLit_t, Comprehension_t,
+        TblComprehension_t, Comprehension_t,
         FunLit_t, Num_t> value;
         AST_MEMBER(SimpleValue, &value)
 AST_END(SimpleValue, "simple_value"sv)
diff --git a/src/yuescript/yue_compiler.cpp b/src/yuescript/yue_compiler.cpp
index 6d33a7e..5a54a05 100644
--- a/src/yuescript/yue_compiler.cpp
+++ b/src/yuescript/yue_compiler.cpp
@@ -71,7 +71,7 @@ static std::unordered_set<std::string> Metamethods = {
         "close"s // Lua 5.4
 };
 
-const std::string_view version = "0.15.21"sv;
+const std::string_view version = "0.15.22"sv;
 const std::string_view extension = "yue"sv;
 
 class YueCompilerImpl {
diff --git a/src/yuescript/yue_parser.cpp b/src/yuescript/yue_parser.cpp
index d23ff4b..e8b47b7 100644
--- a/src/yuescript/yue_parser.cpp
+++ b/src/yuescript/yue_parser.cpp
@@ -56,27 +56,25 @@ YueParser::YueParser() {
         num_char = range('0', '9') >> *(range('0', '9') | expr('_') >> and_(range('0', '9')));
         num_char_hex = range('0', '9') | range('a', 'f') | range('A', 'F');
         num_lit = num_char_hex >> *(num_char_hex | expr('_') >> and_(num_char_hex));
-        Num = (
-                "0x" >> (
-                        +num_lit >> (
-                                '.' >> +num_lit >> -num_expo_hex |
-                                num_expo_hex |
-                                lj_num |
+        Num = sel({
+                expr("0x") >> (
+                        +num_lit >> sel({
+                                seq({expr('.'), +num_lit, -num_expo_hex}),
+                                num_expo_hex,
+                                lj_num,
                                 true_()
-                        ) | (
-                                '.' >> +num_lit >> -num_expo_hex
-                        )
-                )
-        ) | (
-                +num_char >> (
-                        '.' >> +num_char >> -num_expo |
-                        num_expo |
-                        lj_num |
+                        }) | seq({
+                                expr('.'), +num_lit, -num_expo_hex
+                        })
+                ),
+                +num_char >> sel({
+                        seq({expr('.'), +num_char, -num_expo}),
+                        num_expo,
+                        lj_num,
                         true_()
-                )
-        ) | (
-                '.' >> +num_char >> -num_expo
-        );
+                }),
+                seq({expr('.'), +num_char, -num_expo})
+        });
 
         Cut = false_();
         Seperator = true_();
@@ -87,7 +85,6 @@ YueParser::YueParser() {
         });
 
         #define sym(str) (Space >> str)
-        #define symx(str) expr(str)
         #define ensure(patt, finally) ((patt) >> (finally) | (finally) >> Cut)
         #define key(str) (str >> not_(AlphaNum))
         #define disable_do(patt) (DisableDo >> ((patt) >> EnableDo | EnableDo >> Cut))
@@ -133,8 +130,8 @@ YueParser::YueParser() {
         self_class = expr("@@");
         self_class_name = "@@" >> Name;
 
-        SelfName = self_class_name | self_class | self_name | self;
-        KeyName = Space >> (SelfName | Name);
+        SelfName = sel({self_class_name, self_class, self_name, self});
+        KeyName = SelfName | Name;
         VarArg = expr("...");
 
         check_indent = pl::user(Indent, [](const item_t& item) {
@@ -215,22 +212,36 @@ YueParser::YueParser() {
 
         import_literal_inner = (range('a', 'z') | range('A', 'Z') | set("_-")) >> *(AlphaNum | '-');
         import_literal_chain = Seperator >> import_literal_inner >> *(expr('.') >> import_literal_inner);
-        ImportLiteral = sym('\'') >> import_literal_chain >> symx('\'') | sym('"') >> import_literal_chain >> symx('"');
+        ImportLiteral = sym('\'') >> import_literal_chain >> expr('\'') | sym('"') >> import_literal_chain >> expr('"');
 
-        macro_name_pair = Space >> MacroName >> Space >> symx(':') >> Space >> MacroName;
+        macro_name_pair = Space >> MacroName >> Space >> expr(':') >> Space >> MacroName;
         import_all_macro = expr('$');
-        ImportTabItem = variable_pair | normal_pair | sym(':') >> MacroName | macro_name_pair | Space >> import_all_macro | meta_variable_pair | meta_normal_pair | Exp;
+        ImportTabItem = sel({
+                variable_pair,
+                normal_pair,
+                sym(':') >> MacroName,
+                macro_name_pair,
+                Space >> import_all_macro,
+                meta_variable_pair,
+                meta_normal_pair,
+                Exp
+        });
         ImportTabList = ImportTabItem >> *(sym(',') >> ImportTabItem);
         ImportTabLine = (
                 PushIndent >> (ImportTabList >> PopIndent | PopIndent)
         ) | Space;
         import_tab_lines = SpaceBreak >> ImportTabLine >> *(-sym(',') >> SpaceBreak >> ImportTabLine) >> -sym(',');
-        ImportTabLit =
-                Seperator >> (sym('{') >>
-                -ImportTabList >>
-                -sym(',') >>
-                -import_tab_lines >>
-                White >> sym('}') | KeyValue >> *(sym(',') >> KeyValue));
+        ImportTabLit = seq({
+                Seperator,
+                sym('{'),
+                -ImportTabList,
+                -sym(','),
+                -import_tab_lines,
+                White,
+                sym('}')
+        }) | seq({
+                Seperator, KeyValue, *(sym(',') >> KeyValue)
+        });
 
         ImportAs = ImportLiteral >> -(Space >> key("as") >> Space >> (ImportTabLit | Variable | import_all_macro));
 
@@ -273,11 +284,11 @@ YueParser::YueParser() {
         IfElseIf = -(Break >> *EmptyLine >> CheckIndent) >> Space >> key("elseif") >> IfCond >> body_with("then");
         IfElse = -(Break >> *EmptyLine >> CheckIndent) >> Space >> key("else") >> body;
         IfType = (expr("if") | expr("unless")) >> not_(AlphaNum);
-        If = Space >> IfType >> IfCond >> opt_body_with("then") >> *IfElseIf >> -IfElse;
+        If = seq({Space, IfType, IfCond, opt_body_with("then"), *IfElseIf, -IfElse});
 
         WhileType = (expr("while") | expr("until")) >> not_(AlphaNum);
         While = WhileType >> disable_do_chain_arg_table_block(Exp) >> opt_body_with("do");
-        Repeat = key("repeat") >> Body >> Break >> *EmptyLine >> CheckIndent >> Space >> key("until") >> Exp;
+        Repeat = seq({key("repeat"), Body, Break, *EmptyLine, CheckIndent, Space, key("until"), Exp});
 
         for_step_value = sym(',') >> Exp;
         for_args = Space >> Variable >> sym('=') >> Exp >> sym(',') >> Exp >> -for_step_value;
@@ -347,17 +358,21 @@ YueParser::YueParser() {
         CompFor = key("for") >> Space >> Variable >> sym('=') >> Exp >> sym(',') >> Exp >> -for_step_value;
         CompClause = Space >> (CompFor | CompForEach | key("when") >> Exp);
 
-        Assign = sym('=') >> Seperator >> (With | If | Switch | TableBlock | Exp >> *(Space >> set(",;") >> Exp));
+        Assign = sym('=') >> Seperator >> sel({
+                With, If, Switch, TableBlock,
+                Exp >> *(Space >> set(",;") >> Exp)
+        });
 
-        update_op =
-                expr("..") |
-                expr("//") |
-                expr("or") |
-                expr("and") |
-                expr(">>") |
-                expr("<<") |
-                expr("??") |
-                set("+-*/%&|");
+        update_op = sel({
+                expr(".."),
+                expr("//"),
+                expr("or"),
+                expr("and"),
+                expr(">>"),
+                expr("<<"),
+                expr("??"),
+                set("+-*/%&|")
+        });
 
         Update = Space >> update_op >> expr("=") >> Exp;
 
@@ -366,35 +381,37 @@ YueParser::YueParser() {
         unary_value = +(unary_operator >> Space) >> Value;
 
         ExponentialOperator = expr('^');
-        expo_value = Space >> ExponentialOperator >> *SpaceBreak >> Space >> Value;
+        expo_value = seq({Space, ExponentialOperator, *SpaceBreak, Space, Value});
         expo_exp = Value >> *expo_value;
 
-        unary_operator =
-                expr('-') >> not_(set(">=") | space_one) |
-                expr('#') |
-                expr('~') >> not_(expr('=') | space_one) |
-                expr("not") >> not_(AlphaNum);
+        unary_operator = sel({
+                expr('-') >> not_(set(">=") | space_one),
+                expr('#'),
+                expr('~') >> not_(expr('=') | space_one),
+                expr("not") >> not_(AlphaNum)
+        });
         unary_exp = Space >> *(unary_operator >> Space) >> expo_exp;
 
         PipeOperator = expr("|>");
-        pipe_value = Space >> PipeOperator >> *SpaceBreak >> unary_exp;
+        pipe_value = seq({Space, PipeOperator, *SpaceBreak, unary_exp});
         pipe_exp = unary_exp >> *pipe_value;
 
-        BinaryOperator =
-                (expr("or") >> not_(AlphaNum)) |
-                (expr("and") >> not_(AlphaNum)) |
-                expr("<=") |
-                expr(">=") |
-                expr("~=") |
-                expr("!=") |
-                expr("==") |
-                expr("..") |
-                expr("<<") |
-                expr(">>") |
-                expr("//") |
-                set("+-*/%><|&~");
-        exp_op_value = Space >> BinaryOperator >> *SpaceBreak >> pipe_exp;
-        Exp = Seperator >> pipe_exp >> *exp_op_value >> -(Space >> expr("??") >> Exp);
+        BinaryOperator = sel({
+                (expr("or") >> not_(AlphaNum)),
+                (expr("and") >> not_(AlphaNum)),
+                expr("<="),
+                expr(">="),
+                expr("~="),
+                expr("!="),
+                expr("=="),
+                expr(".."),
+                expr("<<"),
+                expr(">>"),
+                expr("//"),
+                set("+-*/%><|&~")
+        });
+        exp_op_value = seq({Space, BinaryOperator, *SpaceBreak, pipe_exp});
+        Exp = seq({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);
@@ -408,24 +425,30 @@ YueParser::YueParser() {
                 return true;
         });
 
-        chain_line = CheckIndent >> Space >> (chain_dot_chain | ColonChain) >> -InvokeArgs;
+        chain_line = seq({CheckIndent, Space, chain_dot_chain | ColonChain, -InvokeArgs});
         chain_block = pl::user(true_(), [](const item_t& item) {
                 State* st = reinterpret_cast<State*>(item.user_data);
                 return st->noChainBlockStack.empty() || !st->noChainBlockStack.top();
         }) >> +SpaceBreak >> Advance >> ensure(
                 chain_line >> *(+SpaceBreak >> chain_line), PopIndent);
-        ChainValue = Seperator >> (Chain | Callable) >> -existential_op >> -(InvokeArgs | chain_block) >> -table_appending_op;
+        ChainValue = seq({
+                Seperator,
+                Chain,
+                -existential_op,
+                -(InvokeArgs | chain_block),
+                -table_appending_op
+        });
 
-        simple_table = Seperator >> KeyValue >> *(sym(',') >> KeyValue);
-        Value = SimpleValue | simple_table | ChainValue | String;
+        simple_table = seq({Seperator, KeyValue, *(sym(',') >> KeyValue)});
+        Value = sel({SimpleValue, simple_table, ChainValue, String});
 
         single_string_inner = expr('\\') >> set("'\\") | not_(expr('\'')) >> Any;
-        SingleString = symx('\'') >> *single_string_inner >> symx('\'');
-        interp = symx("#{") >> Exp >> sym('}');
+        SingleString = expr('\'') >> *single_string_inner >> expr('\'');
+        interp = expr("#{") >> Exp >> sym('}');
         double_string_plain = expr('\\') >> set("\"\\") | not_(expr('"')) >> Any;
         double_string_inner = +(not_(interp) >> double_string_plain);
         double_string_content = double_string_inner | interp;
-        DoubleString = symx('"') >> Seperator >> *double_string_content >> symx('"');
+        DoubleString = expr('"') >> Seperator >> *double_string_content >> expr('"');
         String = DoubleString | SingleString | LuaString;
 
         lua_string_open = '[' >> *expr('=') >> '[';
@@ -448,71 +471,99 @@ YueParser::YueParser() {
 
         LuaString = LuaStringOpen >> -Break >> LuaStringContent >> LuaStringClose;
 
-        Parens = symx('(') >> *SpaceBreak >> Exp >> *SpaceBreak >> sym(')');
-        Callable = Variable | SelfName | MacroName | VarArg | Parens;
-        FnArgsExpList = Exp >> *((Break | sym(',')) >> White >> Exp);
+        Parens = pl::user(seq({expr('('), *SpaceBreak, Exp, *SpaceBreak, Space >> expr(')')}), [](const item_t&) {
+                return true;
+        });
+        Callable = sel({Variable, SelfName, MacroName, VarArg, Parens});
+        FnArgsExpList = Exp >> *seq({Break | Space >> expr(','), White, Exp});
 
-        FnArgs = (symx('(') >> *SpaceBreak >> -FnArgsExpList >> *SpaceBreak >> sym(')')) |
-                (sym('!') >> not_(expr('=')));
+        FnArgs = seq({expr('('), *SpaceBreak, -FnArgsExpList, *SpaceBreak, Space, expr(')')}) |
+                seq({Space, expr('!'), not_(expr('='))});
 
-        meta_index = Name | Index | String;
-        Metatable = expr('<') >> sym('>');
-        Metamethod = expr('<') >> Space >> meta_index >> sym('>');
+        meta_index = sel({Name, Index, String});
+        Metatable = expr('<') >> Space >> expr('>');
+        Metamethod = expr('<') >> Space >> meta_index >> Space >> expr('>');
 
         existential_op = expr('?') >> not_(expr('?'));
         table_appending_op = expr("[]");
-        chain_call = (Callable | String) >> -existential_op >> ChainItems;
-        chain_index_chain = Index >> -existential_op >> -ChainItems;
-        chain_dot_chain = DotChainItem >> -existential_op >> -ChainItems;
-
-        Chain = chain_call | chain_dot_chain | ColonChain | chain_index_chain;
+        chain_call = seq({
+                Callable,
+                -existential_op,
+                -ChainItems
+        }) | seq({
+                String,
+                ChainItems
+        });
+        chain_index_chain = seq({Index, -existential_op, -ChainItems});
+        chain_dot_chain = seq({DotChainItem, -existential_op, -ChainItems});
+
+        Chain = sel({chain_call, chain_dot_chain, ColonChain, chain_index_chain});
+
+        chain_call_list = seq({
+                Callable,
+                -existential_op,
+                ChainItems
+        }) | seq({
+                String,
+                ChainItems
+        });
+        ChainList = sel({chain_call_list, chain_dot_chain, ColonChain, chain_index_chain});
 
-        AssignableChain = Seperator >> Chain;
+        AssignableChain = Seperator >> ChainList;
 
         chain_with_colon = +ChainItem >> -ColonChain;
         ChainItems = chain_with_colon | ColonChain;
 
-        Index = symx('[') >> not_('[') >> Exp >> sym(']');
-        ChainItem = Invoke >> -existential_op | DotChainItem >> -existential_op | Slice | Index >> -existential_op;
-        DotChainItem = symx('.') >> (Name | Metatable | Metamethod);
+        Index = seq({expr('['), not_('['), Exp, Space, expr(']')});
+        ChainItem = sel({
+                Invoke >> -existential_op,
+                DotChainItem >> -existential_op,
+                Slice,
+                Index >> -existential_op
+        });
+        DotChainItem = expr('.') >> (Name | Metatable | Metamethod);
         ColonChainItem = (expr('\\') | expr("::")) >> (LuaKeyword | Name | Metamethod);
         invoke_chain = Invoke >> -existential_op >> -ChainItems;
         ColonChain = ColonChainItem >> -existential_op >> -invoke_chain;
 
         default_value = true_();
-        Slice =
-                symx('[') >> not_('[') >>
-                (Exp | default_value) >>
-                sym(',') >>
-                (Exp | default_value) >>
-                (sym(',') >> Exp | default_value) >>
-                sym(']');
-
-        Invoke = Seperator >> (
-                FnArgs |
-                SingleString |
-                DoubleString |
-                and_(expr('[')) >> LuaString |
-                and_(expr('{')) >> TableLit);
+        Slice = seq({
+                expr('['), not_('['),
+                Exp | default_value,
+                Space, expr(','),
+                Exp | default_value,
+                Space >> expr(',') >> Exp | default_value,
+                Space, expr(']')
+        });
+
+        Invoke = Seperator >> sel({
+                FnArgs,
+                SingleString,
+                DoubleString,
+                and_(expr('[')) >> LuaString,
+                and_(expr('{')) >> TableLit
+        });
 
         SpreadExp = sym("...") >> Exp;
 
-        TableValue =
-                variable_pair_def |
-                normal_pair_def |
-                meta_variable_pair_def |
-                meta_normal_pair_def |
-                SpreadExp |
-                normal_def;
+        TableValue = sel({
+                variable_pair_def,
+                normal_pair_def,
+                meta_variable_pair_def,
+                meta_normal_pair_def,
+                SpreadExp,
+                normal_def
+        });
 
         table_lit_lines = SpaceBreak >> TableLitLine >> *(-sym(',') >> SpaceBreak >> TableLitLine) >> -sym(',');
 
-        TableLit =
-                sym('{') >> Seperator >>
-                -TableValueList >>
-                -sym(',') >>
-                -table_lit_lines >>
-                White >> sym('}');
+        TableLit = seq({
+                sym('{'), Seperator,
+                -TableValueList,
+                -sym(','),
+                -table_lit_lines,
+                White, sym('}')
+        });
 
         TableValueList = TableValue >> *(sym(',') >> TableValue);
 
@@ -575,13 +626,16 @@ YueParser::YueParser() {
 
         variable_pair = sym(':') >> Variable;
 
-        normal_pair = (
-                KeyName |
-                sym('[') >> not_('[') >> Exp >> sym(']') |
-                Space >> String
-        ) >>
-        symx(':') >> not_(':') >>
-        (Exp | TableBlock | +SpaceBreak >> Exp);
+        normal_pair = seq({
+                Space,
+                sel({
+                        KeyName,
+                        seq({expr('['), not_('['), Exp, sym(']')}),
+                        String
+                }),
+                expr(':'), not_(':'),
+                sel({Exp, TableBlock, +SpaceBreak >> Exp})
+        });
 
         meta_variable_pair = sym(":<") >> Space >> Variable >> sym('>');
 
@@ -594,27 +648,31 @@ YueParser::YueParser() {
         meta_normal_pair_def = meta_normal_pair >> -(sym('=') >> Exp);
         normal_def = Exp >> Seperator >> -(sym('=') >> Exp);
 
-        KeyValue = variable_pair | normal_pair | meta_variable_pair | meta_normal_pair;
+        KeyValue = sel({
+                variable_pair,
+                normal_pair,
+                meta_variable_pair,
+                meta_normal_pair
+        });
         KeyValueList = KeyValue >> *(sym(',') >> KeyValue);
         KeyValueLine = CheckIndent >> (KeyValueList >> -sym(',') | TableBlockIndent | Space >> expr('*') >> (SpreadExp | Exp | TableBlock));
 
         FnArgDef = (Variable | SelfName >> -existential_op) >> -(sym('=') >> Space >> Exp);
 
         FnArgDefList = Space >> Seperator >> (
-                (
-                        FnArgDef >>
-                        *((sym(',') | Break) >> White >> FnArgDef) >>
-                        -((sym(',') | Break) >> White >> VarArg)
-                ) | (
+                seq({
+                        FnArgDef,
+                        *seq({(sym(',') | Break), White, FnArgDef}),
+                        -seq({(sym(',') | Break), White, VarArg})
+                }) |
                         VarArg
-                )
         );
 
         outer_var_shadow = Space >> key("using") >> (NameList | Space >> expr("nil"));
 
-        FnArgsDef = sym('(') >> White >> -FnArgDefList >> -outer_var_shadow >> White >> sym(')');
+        FnArgsDef = seq({Space, expr('('), White, -FnArgDefList, -outer_var_shadow, White, Space, expr(')')});
         fn_arrow = expr("->") | expr("=>");
-        FunLit = -FnArgsDef >> Space >> fn_arrow >> -Body;
+        FunLit = seq({-FnArgsDef, Space, fn_arrow, -Body});
 
         MacroName = expr('$') >> Name;
         macro_args_def = sym('(') >> White >> -FnArgDefList >> White >> sym(')');
@@ -627,9 +685,14 @@ YueParser::YueParser() {
         AssignableNameList = Seperator >> NameOrDestructure >> *(sym(',') >> NameOrDestructure);
 
         fn_arrow_back = expr('<') >> set("-=");
-        Backcall = -FnArgsDef >> Space >> fn_arrow_back >> Space >> ChainValue;
+        Backcall = seq({-FnArgsDef, Space, fn_arrow_back, Space, ChainValue});
 
-        PipeBody = Seperator >> PipeOperator >> unary_exp >> *(+SpaceBreak >> CheckIndent >> Space >> PipeOperator >> unary_exp);
+        PipeBody = seq({
+                Seperator,
+                PipeOperator,
+                unary_exp,
+                *seq({+SpaceBreak, CheckIndent, Space, PipeOperator, unary_exp})
+        });
 
         ExpList = Seperator >> Exp >> *(sym(',') >> Exp);
         ExpListLow = Seperator >> Exp >> *(Space >> set(",;") >> Exp);
@@ -661,13 +724,14 @@ YueParser::YueParser() {
                         leading_spaces_error
                 );
 
-        const_value = (expr("nil") | expr("true") | expr("false")) >> not_(AlphaNum);
+        const_value = sel({expr("nil"), expr("true"), expr("false")}) >> not_(AlphaNum);
 
-        SimpleValue =
-                TableLit | const_value | If | Switch | Try | With |
-                ClassDecl | ForEach | For | While | Do |
-                unary_value | TblComprehension | Comprehension |
-                FunLit | Num;
+        SimpleValue = sel({
+                TableLit, const_value, If, Switch, Try, With,
+                ClassDecl, ForEach, For, While, Do,
+                unary_value, TblComprehension, Comprehension,
+                FunLit, Num
+        });
 
         ExpListAssign = ExpList >> -(Update | Assign) >> not_(Space >> expr('='));
 
@@ -683,15 +747,34 @@ YueParser::YueParser() {
         ChainAssign = Seperator >> Exp >> +(sym('=') >> Exp >> Space >> and_('=')) >> Assign;
 
         statement_appendix = (if_line | while_line | CompInner) >> Space;
-        statement_sep = and_(*SpaceBreak >> CheckIndent >> Space >> (set("($'\"") | expr("[[") | expr("[=")));
-        Statement = Seperator >> -(yue_comment >> *(Break >> yue_comment) >> Break >> CheckIndent) >> Space >> (
-                Import | While | Repeat | For | ForEach |
-                Return | Local | Global | Export | Macro |
-                MacroInPlace | BreakLoop | Label | Goto | ShortTabAppending |
-                LocalAttrib | Backcall | PipeBody | ExpListAssign | ChainAssign |
-                statement_appendix >> empty_block_error
-        ) >> Space >>
-        -statement_appendix >> -statement_sep;
+        statement_sep = and_(seq({
+                *SpaceBreak, CheckIndent, Space,
+                sel({
+                        set("($'\""),
+                        expr("[["),
+                        expr("[=")
+                })
+        }));
+        Statement = seq({
+                Seperator,
+                -seq({
+                        yue_comment,
+                        *(Break >> yue_comment),
+                        Break,
+                        CheckIndent
+                }),
+                Space,
+                sel({
+                        Import, While, Repeat, For, ForEach,
+                        Return, Local, Global, Export, Macro,
+                        MacroInPlace, BreakLoop, Label, Goto, ShortTabAppending,
+                        LocalAttrib, Backcall, PipeBody, ExpListAssign, ChainAssign,
+                        statement_appendix >> empty_block_error
+                }),
+                Space,
+                -statement_appendix,
+                -statement_sep
+        });
 
         Body = InBlock | Space >> Statement;
 
@@ -705,15 +788,16 @@ YueParser::YueParser() {
                 return false;
         });
 
-        Line =
-                CheckIndent >> Statement |
-                empty_line_break |
-                Advance >> ensure(Space >> (indentation_error | Statement), PopIndent);
-        Block = Seperator >> Line >> *(+Break >> Line);
+        Line = sel({
+                CheckIndent >> Statement,
+                empty_line_break,
+                Advance >> ensure(Space >> (indentation_error | Statement), PopIndent)
+        });
+        Block = seq({Seperator, Line, *(+Break >> Line)});
 
         Shebang = expr("#!") >> *(not_(Stop) >> Any);
-        BlockEnd = Block >> White >> Stop;
-        File = -Shebang >> -Block >> White >> Stop;
+        BlockEnd = seq({Block, White, Stop});
+        File = seq({-Shebang, -Block, White, Stop});
 }
 // clang-format on
 
diff --git a/src/yuescript/yue_parser.h b/src/yuescript/yue_parser.h
index c37894c..1068468 100644
--- a/src/yuescript/yue_parser.h
+++ b/src/yuescript/yue_parser.h
@@ -176,6 +176,7 @@ private:
         rule for_in;
         rule CompClause;
         rule Chain;
+        rule ChainList;
         rule KeyValue;
         rule single_string_inner;
         rule interp;
@@ -186,6 +187,7 @@ private:
         rule FnArgs;
         rule macro_args_def;
         rule chain_call;
+        rule chain_call_list;
         rule chain_index_chain;
         rule ChainItems;
         rule chain_dot_chain;