diff --git a/ast/nasal_new_ast.h b/ast/nasal_new_ast.h
index e39b78f..ab38ba4 100644
--- a/ast/nasal_new_ast.h
+++ b/ast/nasal_new_ast.h
@@ -96,7 +96,7 @@ public:
     null_expr(const span& location):
         expr(location, expr_type::ast_null) {}
     ~null_expr() = default;
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class nil_expr:public expr {
@@ -104,7 +104,7 @@ public:
     nil_expr(const span& location):
         expr(location, expr_type::ast_nil) {}
     ~nil_expr() = default;
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class number_literal:public expr {
@@ -115,7 +115,7 @@ public:
     number_literal(const span& location, const f64 num):
         expr(location, expr_type::ast_num), number(num) {}
     ~number_literal() = default;
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class string_literal:public expr {
@@ -126,7 +126,7 @@ public:
     string_literal(const span& location, const std::string& str):
         expr(location, expr_type::ast_str), content(str) {}
     ~string_literal() = default;
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class identifier:public expr {
@@ -137,7 +137,7 @@ public:
     identifier(const span& location, const std::string& str):
         expr(location, expr_type::ast_id), name(str) {}
     ~identifier() = default;
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class bool_literal:public expr {
@@ -148,7 +148,7 @@ public:
     bool_literal(const span& location, const bool bool_flag):
         expr(location, expr_type::ast_bool), flag(bool_flag) {}
     ~bool_literal() = default;
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class vector_expr:public expr {
@@ -161,7 +161,7 @@ public:
     ~vector_expr();
     void add_element(expr* node) {elements.push_back(node);}
     std::vector<expr*>& get_elements() {return elements;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class hash_expr:public expr {
@@ -174,7 +174,7 @@ public:
     ~hash_expr();
     void add_member(hash_pair* node) {members.push_back(node);}
     std::vector<hash_pair*>& get_members() {return members;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class hash_pair:public expr {
@@ -190,7 +190,7 @@ public:
     void set_element(expr* node) {element = node;}
     const std::string& get_name() const {return name;}
     expr* get_element() {return element;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class function:public expr {
@@ -207,7 +207,7 @@ public:
     void set_code_block(code_block* node) {block = node;}
     std::vector<parameter*>& get_parameter_list() {return parameter_list;}
     code_block* get_code_block() {return block;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class code_block:public expr {
@@ -220,7 +220,7 @@ public:
     ~code_block();
     void add_expression(expr* node) {expressions.push_back(node);}
     std::vector<expr*>& get_expressions() {return expressions;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class parameter:public expr {
@@ -244,7 +244,7 @@ public:
     void set_parameter_type(param_type pt) {type = pt;}
     void set_parameter_name(identifier* node) {name = node;}
     void set_default_value(expr* node) {default_value = node;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class ternary_operator:public expr {
@@ -258,7 +258,10 @@ public:
         expr(location, expr_type::ast_ternary),
         condition(nullptr), left(nullptr), right(nullptr) {}
     ~ternary_operator();
-    virtual void accept(ast_visitor*) override;
+    void set_condition(expr* node) {condition = node;}
+    void set_left(expr* node) {left = node;}
+    void set_right(expr* node) {right = node;}
+    void accept(ast_visitor*) override;
 };
 
 class binary_operator:public expr {
@@ -277,7 +280,9 @@ public:
         geq,
         bitwise_or,
         bitwise_xor,
-        bitwise_and
+        bitwise_and,
+        condition_and,
+        condition_or
     };
 
 private:
@@ -293,7 +298,7 @@ public:
     void set_type(binary_type operator_type) {type = operator_type;}
     void set_left(expr* node) {left = node;}
     void set_right(expr* node) {right = node;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class unary_operator:public expr {
@@ -315,7 +320,7 @@ public:
     ~unary_operator();
     void set_type(unary_type operator_type) {type = operator_type;}
     void set_value(expr* node) {value = node;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class call_expr:public expr {
@@ -330,7 +335,7 @@ public:
     ~call_expr();
     void set_first(expr* node) {first = node;}
     void add_call(expr* node) {calls.push_back(node);}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class call_hash:public expr {
@@ -342,7 +347,7 @@ public:
         expr(location, expr_type::ast_callh),
         field(name) {}
     ~call_hash();
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class call_vector:public expr {
@@ -355,7 +360,7 @@ public:
     ~call_vector();
     void add_slice(slice_vector* node) {calls.push_back(node);}
     std::vector<slice_vector*>& get_slices() {return calls;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class call_function:public expr {
@@ -368,7 +373,7 @@ public:
     ~call_function();
     void add_argument(expr* node) {args.push_back(node);}
     std::vector<expr*>& get_argument() {return args;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class slice_vector:public expr {
@@ -383,33 +388,39 @@ public:
     ~slice_vector();
     void set_begin(expr* node) {begin = node;}
     void set_end(expr* node) {end = node;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class definition_expr:public expr {
 private:
-    identifier* variable;
+    identifier* variable_name;
     multi_define* variables;
     expr* value;
 
 public:
     definition_expr(const span& location):
         expr(location, expr_type::ast_def),
-        variable(nullptr), variables(nullptr), value(nullptr) {}
+        variable_name(nullptr), variables(nullptr), value(nullptr) {}
     ~definition_expr();
-    virtual void accept(ast_visitor*) override;
+    void set_identifier(identifier* node) {variable_name = node;}
+    void set_multi_define(multi_define* node) {variables = node;}
+    void set_value(expr* node) {value = node;}
+    void accept(ast_visitor*) override;
 };
 
 class multi_define:public expr {
 private:
     std::vector<expr*> variables;
+    expr* value;
 
 public:
     multi_define(const span& location):
-        expr(location, expr_type::ast_multi_id) {}
+        expr(location, expr_type::ast_multi_id),
+        value(nullptr) {}
     ~multi_define();
     void add_var(expr* node) {variables.push_back(node);}
-    virtual void accept(ast_visitor*) override;
+    void set_value(expr* node) {value = node;}
+    void accept(ast_visitor*) override;
 };
 
 class tuple_expr:public expr {
@@ -421,7 +432,7 @@ public:
         expr(location, expr_type::ast_tuple) {}
     ~tuple_expr();
     void add_element(expr* node) {elements.push_back(node);}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class multi_assign:public expr {
@@ -435,7 +446,7 @@ public:
     ~multi_assign();
     void set_left(tuple_expr* node) {left = node;}
     void set_right(expr* node) {right = node;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class while_expr:public expr {
@@ -452,7 +463,7 @@ public:
     void set_code_block (code_block* node) {block = node;}
     expr* get_condition() {return condition;}
     code_block* get_code_block() {return block;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class for_expr:public expr {
@@ -476,7 +487,7 @@ public:
     expr* get_condition() {return condition;}
     expr* get_step() {return step;}
     code_block* get_code_block() {return block;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class iter_expr:public expr {
@@ -493,7 +504,7 @@ public:
     void set_call(expr* node) {call = node;}
     identifier* get_name() {return name;}
     expr* get_call() {return call;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class forei_expr:public expr {
@@ -522,7 +533,7 @@ public:
     iter_expr* get_iterator() {return iterator;}
     expr* get_value() {return vector_node;}
     code_block* get_code_block() {return block;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class condition_expr:public expr {
@@ -542,7 +553,7 @@ public:
     if_expr* get_if_statement() {return if_stmt;}
     std::vector<if_expr*>& get_elsif_stataments() {return elsif_stmt;}
     if_expr* get_else_statement() {return else_stmt;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class if_expr:public expr {
@@ -559,7 +570,7 @@ public:
     void set_code_block(code_block* node) {block = node;}
     expr* get_condition() {return condition;}
     code_block* get_code_block() {return block;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class continue_expr:public expr {
@@ -567,7 +578,7 @@ public:
     continue_expr(const span& location):
         expr(location, expr_type::ast_continue) {}
     ~continue_expr() = default;
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class break_expr:public expr {
@@ -575,7 +586,7 @@ public:
     break_expr(const span& location):
         expr(location, expr_type::ast_break) {}
     ~break_expr() = default;
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
 
 class return_expr:public expr {
@@ -589,5 +600,5 @@ public:
     ~return_expr();
     void set_value(expr* node) {value = node;}
     expr* get_value() {return value;}
-    virtual void accept(ast_visitor*) override;
+    void accept(ast_visitor*) override;
 };
diff --git a/ast/nasal_new_parse.cpp b/ast/nasal_new_parse.cpp
index 1cd9dbe..ffa7c13 100644
--- a/ast/nasal_new_parse.cpp
+++ b/ast/nasal_new_parse.cpp
@@ -408,131 +408,145 @@ expr* parse::calc() {
     auto node = bitwise_or();
     if (lookahead(tok::quesmark)) {
         // trinocular calculation
-        ast tmp(toks[ptr].loc, ast_trino);
+        auto tmp = new ternary_operator(toks[ptr].loc);
         match(tok::quesmark);
-        tmp.add(std::move(node));
-        tmp.add(calc());
+        tmp->set_condition(node);
+        tmp->set_left(calc());
         match(tok::colon);
-        tmp.add(calc());
-        node=std::move(tmp);
+        tmp->set_right(calc());
+        node = tmp;
     } else if (tok::eq<=toks[ptr].type && toks[ptr].type<=tok::lnkeq) {
         // tok::eq~tok::lnkeq is 37 to 42,ast_equal~ast_lnkeq is 21~26
         ast tmp(toks[ptr].loc, (u32)toks[ptr].type-(u32)tok::eq+ast_equal);
         tmp.add(std::move(node));
         match(toks[ptr].type);
         tmp.add(calc());
-        node=std::move(tmp);
+        node = tmp;
     } else if (toks[ptr].type==tok::btandeq || toks[ptr].type==tok::btoreq || toks[ptr].type==tok::btxoreq) {
         ast tmp(toks[ptr].loc, (u32)toks[ptr].type-(u32)tok::btandeq+ast_btandeq);
         tmp.add(std::move(node));
         match(toks[ptr].type);
         tmp.add(calc());
-        node=std::move(tmp);
+        node = tmp;
     }
     update_location(node);
     return node;
 }
 
-binary_operator* parse::bitwise_or() {
-    ast node=bitwise_xor();
+expr* parse::bitwise_or() {
+    auto node = bitwise_xor();
     while(lookahead(tok::btor)) {
-        ast tmp(toks[ptr].loc, ast_bitor);
-        tmp.add(std::move(node));
+        auto tmp = new binary_operator(toks[ptr].loc);
+        tmp->set_type(binary_operator::binary_type::bitwise_or);
+        tmp->set_left(node);
         match(tok::btor);
-        tmp.add(bitwise_xor());
-        tmp.update_span();
-        node=std::move(tmp);
+        tmp->set_right(bitwise_xor());
+        update_location(tmp);
+        node = tmp;
     }
     update_location(node);
     return node;
 }
 
-binary_operator* parse::bitwise_xor() {
-    ast node=bitwise_and();
+expr* parse::bitwise_xor() {
+    auto node = bitwise_and();
     while(lookahead(tok::btxor)) {
-        ast tmp(toks[ptr].loc, ast_bitxor);
-        tmp.add(std::move(node));
+        auto tmp = new binary_operator(toks[ptr].loc);
+        tmp->set_type(binary_operator::binary_type::bitwise_xor);
+        tmp->set_left(node);
         match(tok::btxor);
-        tmp.add(bitwise_and());
-        tmp.update_span();
-        node=std::move(tmp);
+        tmp->set_right(bitwise_and());
+        update_location(tmp);
+        node = tmp;
     }
     update_location(node);
     return node;
 }
 
-binary_operator* parse::bitwise_and() {
-    ast node=or_expr();
+expr* parse::bitwise_and() {
+    auto node = or_expr();
     while(lookahead(tok::btand)) {
-        ast tmp(toks[ptr].loc, ast_bitand);
-        tmp.add(std::move(node));
+        auto tmp = new binary_operator(toks[ptr].loc);
+        tmp->set_type(binary_operator::binary_type::bitwise_and);
+        tmp->set_left(node);
         match(tok::btand);
-        tmp.add(or_expr());
-        tmp.update_span();
-        node=std::move(tmp);
+        tmp->set_right(or_expr());
+        update_location(tmp);
+        node = tmp;
     }
     update_location(node);
     return node;
 }
 
-binary_operator* parse::or_expr() {
-    ast node=and_expr();
+expr* parse::or_expr() {
+    auto node = and_expr();
     while(lookahead(tok::opor)) {
-        ast tmp(toks[ptr].loc, ast_or);
-        tmp.add(std::move(node));
+        auto tmp = new binary_operator(toks[ptr].loc);
+        tmp->set_type(binary_operator::binary_type::condition_or);
+        tmp->set_left(node);
         match(tok::opor);
-        tmp.add(and_expr());
-        tmp.update_span();
-        node=std::move(tmp);
+        tmp->set_right(and_expr());
+        update_location(tmp);
+        node = tmp;
     }
     update_location(node);
     return node;
 }
 
-binary_operator* parse::and_expr() {
-    ast node=cmp_expr();
+expr* parse::and_expr() {
+    auto node = cmp_expr();
     while(lookahead(tok::opand)) {
-        ast tmp(toks[ptr].loc, ast_and);
-        tmp.add(std::move(node));
+        auto tmp = new binary_operator(toks[ptr].loc);
+        tmp->set_type(binary_operator::binary_type::condition_and);
+        tmp->set_left(node);
         match(tok::opand);
-        tmp.add(cmp_expr());
-        tmp.update_span();
-        node=std::move(tmp);
+        tmp->set_right(cmp_expr());
+        update_location(tmp);
+        node = tmp;
     }
     update_location(node);
     return node;
 }
 
-binary_operator* parse::cmp_expr() {
-    ast node=additive_expr();
+expr* parse::cmp_expr() {
+    auto node = additive_expr();
     while(tok::cmpeq<=toks[ptr].type && toks[ptr].type<=tok::geq) {
         // tok::cmpeq~tok::geq is 43~48,ast_cmpeq~ast_geq is 27~32
-        ast tmp(toks[ptr].loc, (u32)toks[ptr].type-(u32)tok::cmpeq+ast_cmpeq);
-        tmp.add(std::move(node));
+        auto tmp = new binary_operator(toks[ptr].loc);
+        switch(toks[ptr].type) {
+            case tok::cmpeq: tmp->set_type(binary_operator::binary_type::cmpeq); break;
+            case tok::neq: tmp->set_type(binary_operator::binary_type::cmpneq); break;
+            case tok::less: tmp->set_type(binary_operator::binary_type::less); break;
+            case tok::leq: tmp->set_type(binary_operator::binary_type::leq); break;
+            case tok::grt: tmp->set_type(binary_operator::binary_type::grt); break;
+            case tok::geq: tmp->set_type(binary_operator::binary_type::geq); break;
+            default: break;
+        }
+        tmp->set_left(node);
         match(toks[ptr].type);
-        tmp.add(additive_expr());
-        tmp.update_span();
-        node=std::move(tmp);
+        tmp->set_right(additive_expr());
+        update_location(tmp);
+        node = tmp;
     }
     update_location(node);
     return node;
 }
 
-binary_operator* parse::additive_expr() {
-    ast node=multive_expr();
+expr* parse::additive_expr() {
+    auto node = multive_expr();
     while(lookahead(tok::add) || lookahead(tok::sub) || lookahead(tok::floater)) {
-        ast tmp(toks[ptr].loc, ast_null);
+        auto tmp = new binary_operator(toks[ptr].loc);
         switch(toks[ptr].type) {
-            case tok::add: tmp.set_type(ast_add);  break;
-            case tok::sub: tmp.set_type(ast_sub);  break;
-            case tok::floater: tmp.set_type(ast_link); break;
+            case tok::add: tmp->set_type(binary_operator::binary_type::add); break;
+            case tok::sub: tmp->set_type(binary_operator::binary_type::sub); break;
+            case tok::floater: tmp->set_type(binary_operator::binary_type::concat); break;
             default: break;
         }
-        tmp.add(std::move(node));
+        tmp->set_left(node);
         match(toks[ptr].type);
-        tmp.add(multive_expr());
-        tmp.update_span();
-        node=std::move(tmp);
+        tmp->set_right(multive_expr());
+        update_location(tmp);
+        node = tmp;
     }
     update_location(node);
     return node;
@@ -582,47 +596,48 @@ unary_operator* parse::unary() {
 expr* parse::scalar() {
     expr* node = nullptr;
     if (lookahead(tok::tknil)) {
-        node=nil();
+        node = nil();
         match(tok::tknil);
     } else if (lookahead(tok::num)) {
-        node=num();
+        node = num();
     } else if (lookahead(tok::str)) {
-        node=str();
+        node = str();
     } else if (lookahead(tok::id)) {
-        node=id();
+        node = id();
     } else if (lookahead(tok::tktrue) || lookahead(tok::tkfalse)) {
-        node=bools();
+        node = bools();
     } else if (lookahead(tok::func)) {
-        node=func();
+        node = func();
     } else if (lookahead(tok::lbracket)) {
-        node=vec();
+        node = vec();
     } else if (lookahead(tok::lbrace)) {
-        node=hash();
+        node = hash();
     } else if (lookahead(tok::lcurve)) {
         const auto& loc=toks[ptr].loc;
         match(tok::lcurve);
-        node=calc();
+        node = calc();
         node->set_begin(loc.begin_line, loc.begin_column);
         update_location(node);
         match(tok::rcurve);
     } else if (lookahead(tok::var)) {
         match(tok::var);
-        node.set_type(ast_def);
-        node.add(id());
+        auto def_node = new definition_expr(toks[ptr].loc);
+        def_node->set_identifier(id());
         match(tok::eq);
-        node.add(calc());
+        def_node->set_value(calc());
+        node = def_node;
     } else {
         die(thisspan, "expected scalar");
         return node;
     }
     // check call and avoid ambiguous syntax
     if (is_call(toks[ptr].type) && !(lookahead(tok::lcurve) && toks[ptr+1].type==tok::var)) {
-        ast tmp=std::move(node);
-        node={toks[ptr].loc, ast_call};
-        node.add(std::move(tmp));
+        auto call_node = new call_expr(toks[ptr].loc);
+        call_node->set_first(node);
         while(is_call(toks[ptr].type)) {
-            node.add(call_scalar());
+            call_node->add_call(call_scalar());
         }
+        node = call_node;
     }
     update_location(node);
     return node;
@@ -721,18 +736,18 @@ expr* parse::definition() {
     if (lookahead(tok::var)) {
         match(tok::var);
         switch(toks[ptr].type) {
-            case tok::id: node.add(id());break;
-            case tok::lcurve: node.add(outcurve_def());break;
+            case tok::id: node->set_identifier(id());break;
+            case tok::lcurve: node->set_multi_define(outcurve_def());break;
             default: die(thisspan, "expected identifier");break;
         }
     } else if (lookahead(tok::lcurve)) {
-        node.add(incurve_def());
+        node->set_multi_define(incurve_def());
     }
     match(tok::eq);
     if (lookahead(tok::lcurve)) {
-        node.add(check_tuple()?multi_scalar():calc());
+        node->set_value(check_tuple()?multi_scalar():calc());
     } else {
-        node.add(calc());
+        node->set_value(calc());
     }
     update_location(node);
     return node;
@@ -759,7 +774,7 @@ multi_define* parse::outcurve_def() {
     return node;
 }
 
-expr* parse::multi_id() {
+multi_define* parse::multi_id() {
     auto node = new multi_define(toks[ptr].loc);
     while(!lookahead(tok::eof)) {
         // only identifier is allowed here
diff --git a/ast/nasal_new_parse.h b/ast/nasal_new_parse.h
index 8addbe3..9753bc5 100644
--- a/ast/nasal_new_parse.h
+++ b/ast/nasal_new_parse.h
@@ -105,13 +105,13 @@ private:
     expr* expression();
     code_block* expression_block();
     expr* calc();
-    binary_operator* bitwise_or();
-    binary_operator* bitwise_xor();
-    binary_operator* bitwise_and();
-    binary_operator* or_expr();
-    binary_operator* and_expr();
-    binary_operator* cmp_expr();
-    binary_operator* additive_expr();
+    expr* bitwise_or();
+    expr* bitwise_xor();
+    expr* bitwise_and();
+    expr* or_expr();
+    expr* and_expr();
+    expr* cmp_expr();
+    expr* additive_expr();
     expr* multive_expr();
     unary_operator* unary();
     expr* scalar();