diff --git a/ast/ast_dumper.cpp b/ast/ast_dumper.cpp
new file mode 100644
index 0000000..0aaba4a
--- /dev/null
+++ b/ast/ast_dumper.cpp
@@ -0,0 +1,368 @@
+#include "ast_dumper.h"
+
+#include <iostream>
+
+bool ast_dumper::visit_expr(expr* node) {
+    std::cout << "expr\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    node->accept(this);
+    return true;
+}
+
+bool ast_dumper::visit_null_expr(null_expr* node) {
+    std::cout << "null\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    return true;
+}
+
+bool ast_dumper::visit_nil_expr(nil_expr* node) {
+    std::cout << "nil\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    return true;
+}
+
+bool ast_dumper::visit_number_literal(number_literal* node) {
+    std::cout << "number " << node->get_number() << "\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    return true;
+}
+
+bool ast_dumper::visit_string_literal(string_literal* node) {
+    std::cout << "string " << node->get_content() << "\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    return true;
+}
+
+bool ast_dumper::visit_identifier(identifier* node) {
+    std::cout << "identifier " << node->get_name() << "\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    return true;
+}
+
+bool ast_dumper::visit_bool_literal(bool_literal* node) {
+    std::cout << "bool " << node->get_flag() << "\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    return true;
+}
+
+bool ast_dumper::visit_vector_expr(vector_expr* node) {
+    std::cout << "vector\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    for(auto i : node->get_elements()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_dumper::visit_hash_expr(hash_expr* node) {
+    std::cout << "hash\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    for(auto i : node->get_members()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_dumper::visit_hash_pair(hash_pair* node) {
+    std::cout << "pair\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    if (node->get_value()) {
+        node->get_value()->accept(this);
+    }
+    return true;
+}
+
+bool ast_dumper::visit_function(function* node) {
+    std::cout << "function\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    for(auto i : node->get_parameter_list()) {
+        i->accept(this);
+    }
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_dumper::visit_code_block(code_block* node) {
+    std::cout << "block\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    for(auto i : node->get_expressions()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_dumper::visit_parameter(parameter* node) {
+    std::cout << "parameter\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    node->get_parameter_name()->accept(this);
+    if (node->get_default_value()) {
+        node->get_default_value()->accept(this);
+    }
+    return true;
+}
+
+bool ast_dumper::visit_ternary_operator(ternary_operator* node) {
+    std::cout << "ternary\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    node->get_condition()->accept(this);
+    node->get_left()->accept(this);
+    node->get_right()->accept(this);
+    return true;
+}
+
+bool ast_dumper::visit_binary_operator(binary_operator* node) {
+    std::cout << "binary\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    node->get_left()->accept(this);
+    node->get_right()->accept(this);
+    return true;
+}
+
+bool ast_dumper::visit_unary_operator(unary_operator* node) {
+    std::cout << "unary\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    node->get_value()->accept(this);
+    return true;
+}
+
+bool ast_dumper::visit_call_expr(call_expr* node) {
+    std::cout << "call_expr\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    node->get_first()->accept(this);
+    for(auto i : node->get_calls()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_dumper::visit_call_hash(call_hash* node) {
+    std::cout << "call_hash\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    return true;
+}
+
+bool ast_dumper::visit_call_vector(call_vector* node) {
+    std::cout << "call_vector\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    for(auto i : node->get_slices()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_dumper::visit_call_function(call_function* node) {
+    std::cout << "call_function\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    for(auto i : node->get_argument()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_dumper::visit_slice_vector(slice_vector* node) {
+    std::cout << "slice\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    node->get_begin()->accept(this);
+    if (node->get_end()) {
+        node->get_end()->accept(this);
+    }
+    return true;
+}
+
+bool ast_dumper::visit_definition_expr(definition_expr* node) {
+    std::cout << "definition\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    if (node->get_variable_name()) {
+        node->get_variable_name()->accept(this);
+    } else {
+        node->get_variables()->accept(this);
+    }
+    node->get_value()->accept(this);
+    return true;
+}
+
+bool ast_dumper::visit_assignment_expr(assignment_expr* node) {
+    std::cout << "assignment\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    node->get_left()->accept(this);
+    node->get_right()->accept(this);
+    return true;
+}
+
+bool ast_dumper::visit_multi_identifier(multi_identifier* node) {
+    std::cout << "multi_define\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    for(auto i : node->get_variables()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_dumper::visit_tuple_expr(tuple_expr* node) {
+    std::cout << "tuple\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    for(auto i : node->get_elements()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_dumper::visit_multi_assign(multi_assign* node) {
+    std::cout << "multi_assign\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    node->get_tuple()->accept(this);
+    node->get_value()->accept(this);
+    return true;
+}
+
+bool ast_dumper::visit_while_expr(while_expr* node) {
+    std::cout << "while\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    node->get_condition()->accept(this);
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_dumper::visit_for_expr(for_expr* node) {
+    std::cout << "for\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    node->get_initial()->accept(this);
+    node->get_condition()->accept(this);
+    node->get_step()->accept(this);
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_dumper::visit_iter_expr(iter_expr* node) {
+    std::cout << "iter\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    if (node->get_name()) {
+        node->get_name()->accept(this);
+    } else {
+        node->get_call()->accept(this);
+    }
+    return true;
+}
+
+bool ast_dumper::visit_forei_expr(forei_expr* node) {
+    std::cout << "forei\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    node->get_iterator()->accept(this);
+    node->get_value()->accept(this);
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_dumper::visit_condition_expr(condition_expr* node) {
+    std::cout << "condition\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    node->get_if_statement()->accept(this);
+    for(auto i : node->get_elsif_stataments()) {
+        i->accept(this);
+    }
+    if (node->get_else_statement()) {
+        node->get_else_statement()->accept(this);
+    }
+    return true;
+}
+
+bool ast_dumper::visit_if_expr(if_expr* node) {
+    std::cout << "if\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    if (node->get_condition()) {
+        node->get_condition()->accept(this);
+    }
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_dumper::visit_continue_expr(continue_expr* node) {
+    std::cout << "continue\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    return true;
+}
+
+bool ast_dumper::visit_break_expr(break_expr* node) {
+    std::cout << "break\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    return true;
+}
+
+bool ast_dumper::visit_return_expr(return_expr* node) {
+    std::cout << "return\n";
+    std::cout << " -> " << node->get_location().file << ":"
+    << node->get_location().begin_line << ":"
+    << node->get_location().begin_column << "\n";
+    if (node->get_value()) {
+        node->get_value()->accept(this);
+    }
+    return true;
+}
\ No newline at end of file
diff --git a/ast/ast_dumper.h b/ast/ast_dumper.h
new file mode 100644
index 0000000..4599537
--- /dev/null
+++ b/ast/ast_dumper.h
@@ -0,0 +1,42 @@
+#pragma once
+
+#include "ast_visitor.h"
+
+class ast_dumper:public ast_visitor {
+public:
+    bool visit_expr(expr*) override;
+    bool visit_null_expr(null_expr*) override;
+    bool visit_nil_expr(nil_expr*) override;
+    bool visit_number_literal(number_literal*) override;
+    bool visit_string_literal(string_literal*) override;
+    bool visit_identifier(identifier*) override;
+    bool visit_bool_literal(bool_literal*) override;
+    bool visit_vector_expr(vector_expr*) override;
+    bool visit_hash_expr(hash_expr*) override;
+    bool visit_hash_pair(hash_pair*) override;
+    bool visit_function(function*) override;
+    bool visit_code_block(code_block*) override;
+    bool visit_parameter(parameter*) override;
+    bool visit_ternary_operator(ternary_operator*) override;
+    bool visit_binary_operator(binary_operator*) override;
+    bool visit_unary_operator(unary_operator*) override;
+    bool visit_call_expr(call_expr*) override;
+    bool visit_call_hash(call_hash*) override;
+    bool visit_call_vector(call_vector*) override;
+    bool visit_call_function(call_function*) override;
+    bool visit_slice_vector(slice_vector*) override;
+    bool visit_definition_expr(definition_expr*) override;
+    bool visit_assignment_expr(assignment_expr*) override;
+    bool visit_multi_identifier(multi_identifier*) override;
+    bool visit_tuple_expr(tuple_expr*) override;
+    bool visit_multi_assign(multi_assign*) override;
+    bool visit_while_expr(while_expr*) override;
+    bool visit_for_expr(for_expr*) override;
+    bool visit_iter_expr(iter_expr*) override;
+    bool visit_forei_expr(forei_expr*) override;
+    bool visit_condition_expr(condition_expr*) override;
+    bool visit_if_expr(if_expr*) override;
+    bool visit_continue_expr(continue_expr*) override;
+    bool visit_break_expr(break_expr*) override;
+    bool visit_return_expr(return_expr*) override;
+};
\ No newline at end of file
diff --git a/ast/ast_visitor.cpp b/ast/ast_visitor.cpp
index 017a0e7..e641856 100644
--- a/ast/ast_visitor.cpp
+++ b/ast/ast_visitor.cpp
@@ -44,8 +44,183 @@ bool ast_visitor::visit_hash_expr(hash_expr* node) {
 }
 
 bool ast_visitor::visit_hash_pair(hash_pair* node) {
-    if (node->get_element()) {
-        node->get_element()->accept(this);
+    if (node->get_value()) {
+        node->get_value()->accept(this);
+    }
+    return true;
+}
+
+bool ast_visitor::visit_function(function* node) {
+    for(auto i : node->get_parameter_list()) {
+        i->accept(this);
+    }
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_visitor::visit_code_block(code_block* node) {
+    for(auto i : node->get_expressions()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_visitor::visit_parameter(parameter* node) {
+    node->get_parameter_name()->accept(this);
+    if (node->get_default_value()) {
+        node->get_default_value()->accept(this);
+    }
+    return true;
+}
+
+bool ast_visitor::visit_ternary_operator(ternary_operator* node) {
+    node->get_condition()->accept(this);
+    node->get_left()->accept(this);
+    node->get_right()->accept(this);
+    return true;
+}
+
+bool ast_visitor::visit_binary_operator(binary_operator* node) {
+    node->get_left()->accept(this);
+    node->get_right()->accept(this);
+    return true;
+}
+
+bool ast_visitor::visit_unary_operator(unary_operator* node) {
+    node->get_value()->accept(this);
+    return true;
+}
+
+bool ast_visitor::visit_call_expr(call_expr* node) {
+    node->get_first()->accept(this);
+    for(auto i : node->get_calls()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_visitor::visit_call_hash(call_hash* node) {
+    return true;
+}
+
+bool ast_visitor::visit_call_vector(call_vector* node) {
+    for(auto i : node->get_slices()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_visitor::visit_call_function(call_function* node) {
+    for(auto i : node->get_argument()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_visitor::visit_slice_vector(slice_vector* node) {
+    node->get_begin()->accept(this);
+    if (node->get_end()) {
+        node->get_end()->accept(this);
+    }
+    return true;
+}
+
+bool ast_visitor::visit_definition_expr(definition_expr* node) {
+    if (node->get_variable_name()) {
+        node->get_variable_name()->accept(this);
+    } else {
+        node->get_variables()->accept(this);
+    }
+    node->get_value()->accept(this);
+    return true;
+}
+
+bool ast_visitor::visit_assignment_expr(assignment_expr* node) {
+    node->get_left()->accept(this);
+    node->get_right()->accept(this);
+    return true;
+}
+
+bool ast_visitor::visit_multi_identifier(multi_identifier* node) {
+    for(auto i : node->get_variables()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_visitor::visit_tuple_expr(tuple_expr* node) {
+    for(auto i : node->get_elements()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_visitor::visit_multi_assign(multi_assign* node) {
+    node->get_tuple()->accept(this);
+    node->get_value()->accept(this);
+    return true;
+}
+
+bool ast_visitor::visit_while_expr(while_expr* node) {
+    node->get_condition()->accept(this);
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_visitor::visit_for_expr(for_expr* node) {
+    node->get_initial()->accept(this);
+    node->get_condition()->accept(this);
+    node->get_step()->accept(this);
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_visitor::visit_iter_expr(iter_expr* node) {
+    if (node->get_name()) {
+        node->get_name()->accept(this);
+    } else {
+        node->get_call()->accept(this);
+    }
+    return true;
+}
+
+bool ast_visitor::visit_forei_expr(forei_expr* node) {
+    node->get_iterator()->accept(this);
+    node->get_value()->accept(this);
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_visitor::visit_condition_expr(condition_expr* node) {
+    node->get_if_statement()->accept(this);
+    for(auto i : node->get_elsif_stataments()) {
+        i->accept(this);
+    }
+    if (node->get_else_statement()) {
+        node->get_else_statement()->accept(this);
+    }
+    return true;
+}
+
+bool ast_visitor::visit_if_expr(if_expr* node) {
+    if (node->get_condition()) {
+        node->get_condition()->accept(this);
+    }
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_visitor::visit_continue_expr(continue_expr* node) {
+    return true;
+}
+
+bool ast_visitor::visit_break_expr(break_expr* node) {
+    return true;
+}
+
+bool ast_visitor::visit_return_expr(return_expr* node) {
+    if (node->get_value()) {
+        node->get_value()->accept(this);
     }
     return true;
 }
\ No newline at end of file
diff --git a/ast/ast_visitor.h b/ast/ast_visitor.h
index 92d42b2..ff30483 100644
--- a/ast/ast_visitor.h
+++ b/ast/ast_visitor.h
@@ -14,4 +14,29 @@ public:
     virtual bool visit_vector_expr(vector_expr*);
     virtual bool visit_hash_expr(hash_expr*);
     virtual bool visit_hash_pair(hash_pair*);
+    virtual bool visit_function(function*);
+    virtual bool visit_code_block(code_block*);
+    virtual bool visit_parameter(parameter*);
+    virtual bool visit_ternary_operator(ternary_operator*);
+    virtual bool visit_binary_operator(binary_operator*);
+    virtual bool visit_unary_operator(unary_operator*);
+    virtual bool visit_call_expr(call_expr*);
+    virtual bool visit_call_hash(call_hash*);
+    virtual bool visit_call_vector(call_vector*);
+    virtual bool visit_call_function(call_function*);
+    virtual bool visit_slice_vector(slice_vector*);
+    virtual bool visit_definition_expr(definition_expr*);
+    virtual bool visit_assignment_expr(assignment_expr*);
+    virtual bool visit_multi_identifier(multi_identifier*);
+    virtual bool visit_tuple_expr(tuple_expr*);
+    virtual bool visit_multi_assign(multi_assign*);
+    virtual bool visit_while_expr(while_expr*);
+    virtual bool visit_for_expr(for_expr*);
+    virtual bool visit_iter_expr(iter_expr*);
+    virtual bool visit_forei_expr(forei_expr*);
+    virtual bool visit_condition_expr(condition_expr*);
+    virtual bool visit_if_expr(if_expr*);
+    virtual bool visit_continue_expr(continue_expr*);
+    virtual bool visit_break_expr(break_expr*);
+    virtual bool visit_return_expr(return_expr*);
 };
\ No newline at end of file
diff --git a/ast/nasal_new_ast.cpp b/ast/nasal_new_ast.cpp
index b487fe4..c6d7c16 100644
--- a/ast/nasal_new_ast.cpp
+++ b/ast/nasal_new_ast.cpp
@@ -50,8 +50,8 @@ void hash_expr::accept(ast_visitor* visitor) {
 }
 
 hash_pair::~hash_pair() {
-    if (element) {
-        delete element;
+    if (value) {
+        delete value;
     }
 }
 
@@ -69,7 +69,7 @@ function::~function() {
 }
 
 void function::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_function(this);
 }
 
 code_block::~code_block() {
@@ -79,7 +79,7 @@ code_block::~code_block() {
 }
 
 void code_block::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_code_block(this);
 }
 
 parameter::~parameter() {
@@ -92,7 +92,7 @@ parameter::~parameter() {
 }
 
 void parameter::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_parameter(this);
 }
 
 ternary_operator::~ternary_operator() {
@@ -108,7 +108,7 @@ ternary_operator::~ternary_operator() {
 }
 
 void ternary_operator::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_ternary_operator(this);
 }
 
 binary_operator::~binary_operator() {
@@ -121,7 +121,7 @@ binary_operator::~binary_operator() {
 }
 
 void binary_operator::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_binary_operator(this);
 }
 
 unary_operator::~unary_operator() {
@@ -131,7 +131,7 @@ unary_operator::~unary_operator() {
 }
 
 void unary_operator::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_unary_operator(this);
 }
 
 call_expr::~call_expr() {
@@ -144,11 +144,11 @@ call_expr::~call_expr() {
 }
 
 void call_expr::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_call_expr(this);
 }
 
 void call_hash::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_call_hash(this);
 }
 
 call_vector::~call_vector() {
@@ -158,7 +158,7 @@ call_vector::~call_vector() {
 }
 
 void call_vector::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_call_vector(this);
 }
 
 call_function::~call_function() {
@@ -168,7 +168,7 @@ call_function::~call_function() {
 }
 
 void call_function::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_call_function(this);
 }
 
 slice_vector::~slice_vector() {
@@ -181,7 +181,7 @@ slice_vector::~slice_vector() {
 }
 
 void slice_vector::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_slice_vector(this);
 }
 
 definition_expr::~definition_expr() {
@@ -197,7 +197,7 @@ definition_expr::~definition_expr() {
 }
 
 void definition_expr::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_definition_expr(this);
 }
 
 assignment_expr::~assignment_expr() {
@@ -210,20 +210,17 @@ assignment_expr::~assignment_expr() {
 }
 
 void assignment_expr::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_assignment_expr(this);
 }
 
-multi_define::~multi_define() {
+multi_identifier::~multi_identifier() {
     for(auto i : variables) {
         delete i;
     }
-    if (value) {
-        delete value;
-    }
 }
 
-void multi_define::accept(ast_visitor* visitor) {
-    // TODO
+void multi_identifier::accept(ast_visitor* visitor) {
+    visitor->visit_multi_identifier(this);
 }
 
 tuple_expr::~tuple_expr() {
@@ -233,20 +230,20 @@ tuple_expr::~tuple_expr() {
 }
 
 void tuple_expr::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_tuple_expr(this);
 }
 
 multi_assign::~multi_assign() {
-    if (left) {
-        delete left;
+    if (tuple) {
+        delete tuple;
     }
-    if (right) {
-        delete right;
+    if (value) {
+        delete value;
     }
 }
 
 void multi_assign::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_multi_assign(this);
 }
 
 while_expr::~while_expr() {
@@ -259,7 +256,7 @@ while_expr::~while_expr() {
 }
 
 void while_expr::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_while_expr(this);
 }
 
 for_expr::~for_expr() {
@@ -278,7 +275,7 @@ for_expr::~for_expr() {
 }
 
 void for_expr::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_for_expr(this);
 }
 
 iter_expr::~iter_expr() {
@@ -291,7 +288,7 @@ iter_expr::~iter_expr() {
 }
 
 void iter_expr::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_iter_expr(this);
 }
 
 forei_expr::~forei_expr() {
@@ -307,7 +304,7 @@ forei_expr::~forei_expr() {
 }
 
 void forei_expr::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_forei_expr(this);
 }
 
 condition_expr::~condition_expr() {
@@ -323,7 +320,7 @@ condition_expr::~condition_expr() {
 }
 
 void condition_expr::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_condition_expr(this);
 }
 
 if_expr::~if_expr() {
@@ -336,15 +333,15 @@ if_expr::~if_expr() {
 }
 
 void if_expr::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_if_expr(this);
 }
 
 void continue_expr::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_continue_expr(this);
 }
 
 void break_expr::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_break_expr(this);
 }
 
 return_expr::~return_expr() {
@@ -354,5 +351,5 @@ return_expr::~return_expr() {
 }
 
 void return_expr::accept(ast_visitor* visitor) {
-    // TODO
+    visitor->visit_return_expr(this);
 }
\ No newline at end of file
diff --git a/ast/nasal_new_ast.h b/ast/nasal_new_ast.h
index 2de3937..58ec85d 100644
--- a/ast/nasal_new_ast.h
+++ b/ast/nasal_new_ast.h
@@ -8,8 +8,7 @@
 
 enum class expr_type:u32 {
     ast_null=0,      // null node
-    ast_expr,        // expression node
-    ast_block,       // expression block 
+    ast_block,       // code block 
     ast_nil,         // nil keyword
     ast_num,         // number, basic value type
     ast_str,         // string, basic value type
@@ -24,21 +23,7 @@ enum class expr_type:u32 {
     ast_callv,       // id[index]
     ast_callf,       // id()
     ast_subvec,      // id[index:index]
-
     ast_param,       // function parameter
-    ast_and,         // and keyword
-    ast_or,          // or keyword
-
-    ast_equal,       // =
-    ast_addeq,       // +=
-    ast_subeq,       // -=
-    ast_multeq,      // *=
-    ast_diveq,       // /=
-    ast_lnkeq,       // ~=
-    ast_btandeq,     // &=
-    ast_btoreq,      // |=
-    ast_btxoreq,     // ^=
-
     ast_ternary,
     ast_binary,
     ast_unary,
@@ -62,23 +47,18 @@ class ast_visitor;
 class hash_pair;
 class parameter;
 class slice_vector;
-class multi_define;
+class multi_identifier;
 class code_block;
 class if_expr;
 
 class ast_abstract_node {
-public:
-    virtual void accept(ast_visitor*) = 0;
-};
-
-class expr:public ast_abstract_node {
-private:
+protected:
     span nd_loc;
     expr_type nd_type;
+
 public:
-    expr(const span& location, expr_type node_type):
+    ast_abstract_node(const span& location, expr_type node_type):
         nd_loc(location), nd_type(node_type) {}
-    ~expr() = default;
     void set_begin(u32 line, u32 column) {
         nd_loc.begin_line = line;
         nd_loc.begin_column = column;
@@ -89,6 +69,14 @@ public:
         nd_loc.end_line = location.end_line;
         nd_loc.end_column = location.end_column;
     }
+    virtual void accept(ast_visitor*) = 0;
+};
+
+class expr:public ast_abstract_node {
+public:
+    expr(const span& location, expr_type node_type):
+        ast_abstract_node(location, node_type) {}
+    ~expr() = default;
     void accept(ast_visitor*);
 };
 
@@ -152,6 +140,7 @@ public:
     bool_literal(const span& location, const bool bool_flag):
         expr(location, expr_type::ast_bool), flag(bool_flag) {}
     ~bool_literal() = default;
+    bool get_flag() const {return flag;}
     void accept(ast_visitor*) override;
 };
 
@@ -184,16 +173,17 @@ public:
 class hash_pair:public expr {
 private:
     std::string name;
-    expr* element;
+    expr* value;
 
 public:
     hash_pair(const span& location):
-        expr(location, expr_type::ast_pair) {}
+        expr(location, expr_type::ast_pair),
+        value(nullptr) {}
     ~hash_pair();
     void set_name(const std::string& field_name) {name = field_name;}
-    void set_element(expr* node) {element = node;}
+    void set_value(expr* node) {value = node;}
     const std::string& get_name() const {return name;}
-    expr* get_element() {return element;}
+    expr* get_value() {return value;}
     void accept(ast_visitor*) override;
 };
 
@@ -248,6 +238,9 @@ 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;}
+    param_type get_type() {return type;}
+    identifier* get_parameter_name() {return name;}
+    expr* get_default_value() {return default_value;}
     void accept(ast_visitor*) override;
 };
 
@@ -265,6 +258,9 @@ public:
     void set_condition(expr* node) {condition = node;}
     void set_left(expr* node) {left = node;}
     void set_right(expr* node) {right = node;}
+    expr* get_condition() {return condition;}
+    expr* get_left() {return left;}
+    expr* get_right() {return right;}
     void accept(ast_visitor*) override;
 };
 
@@ -302,6 +298,9 @@ 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;}
+    binary_type get_type() const {return type;}
+    expr* get_left() {return left;}
+    expr* get_right() {return right;}
     void accept(ast_visitor*) override;
 };
 
@@ -324,6 +323,8 @@ public:
     ~unary_operator();
     void set_type(unary_type operator_type) {type = operator_type;}
     void set_value(expr* node) {value = node;}
+    unary_type get_type() const {return type;}
+    expr* get_value() {return value;}
     void accept(ast_visitor*) override;
 };
 
@@ -339,6 +340,8 @@ public:
     ~call_expr();
     void set_first(expr* node) {first = node;}
     void add_call(expr* node) {calls.push_back(node);}
+    expr* get_first() {return first;}
+    std::vector<expr*>& get_calls() {return calls;}
     void accept(ast_visitor*) override;
 };
 
@@ -351,6 +354,7 @@ public:
         expr(location, expr_type::ast_callh),
         field(name) {}
     ~call_hash() = default;
+    const std::string& get_field() const {return field;}
     void accept(ast_visitor*) override;
 };
 
@@ -392,13 +396,15 @@ public:
     ~slice_vector();
     void set_begin(expr* node) {begin = node;}
     void set_end(expr* node) {end = node;}
+    expr* get_begin() {return begin;}
+    expr* get_end() {return end;}
     void accept(ast_visitor*) override;
 };
 
 class definition_expr:public expr {
 private:
     identifier* variable_name;
-    multi_define* variables;
+    multi_identifier* variables;
     expr* value;
 
 public:
@@ -407,9 +413,10 @@ public:
         variable_name(nullptr), variables(nullptr), value(nullptr) {}
     ~definition_expr();
     void set_identifier(identifier* node) {variable_name = node;}
-    void set_multi_define(multi_define* node) {variables = node;}
+    void set_multi_define(multi_identifier* node) {variables = node;}
     void set_value(expr* node) {value = node;}
-
+    identifier* get_variable_name() {return variable_name;}
+    multi_identifier* get_variables() {return variables;}
     expr* get_value() {return value;}
     void accept(ast_visitor*) override;
 };
@@ -441,25 +448,22 @@ public:
     void set_type(assign_type operator_type) {type = operator_type;}
     void set_left(expr* node) {left = node;}
     void set_right(expr* node) {right = node;}
-
     assign_type get_type() const {return type;}
     expr* get_left() {return left;}
     expr* get_right() {return right;}
     void accept(ast_visitor*) override;
 };
 
-class multi_define:public expr {
+class multi_identifier:public expr {
 private:
     std::vector<expr*> variables;
-    expr* value;
 
 public:
-    multi_define(const span& location):
-        expr(location, expr_type::ast_multi_id),
-        value(nullptr) {}
-    ~multi_define();
+    multi_identifier(const span& location):
+        expr(location, expr_type::ast_multi_id) {}
+    ~multi_identifier();
     void add_var(expr* node) {variables.push_back(node);}
-    void set_value(expr* node) {value = node;}
+    std::vector<expr*>& get_variables() {return variables;}
     void accept(ast_visitor*) override;
 };
 
@@ -472,20 +476,24 @@ public:
         expr(location, expr_type::ast_tuple) {}
     ~tuple_expr();
     void add_element(expr* node) {elements.push_back(node);}
+    std::vector<expr*>& get_elements() {return elements;}
     void accept(ast_visitor*) override;
 };
 
 class multi_assign:public expr {
 private:
-    tuple_expr* left;
-    expr* right;
+    tuple_expr* tuple;
+    expr* value;
 
 public:
     multi_assign(const span& location):
-        expr(location, expr_type::ast_multi_assign) {}
+        expr(location, expr_type::ast_multi_assign),
+        tuple(nullptr), value(nullptr) {}
     ~multi_assign();
-    void set_left(tuple_expr* node) {left = node;}
-    void set_right(expr* node) {right = node;}
+    void set_tuple(tuple_expr* node) {tuple = node;}
+    void set_value(expr* node) {value = node;}
+    tuple_expr* get_tuple() {return tuple;}
+    expr* get_value() {return value;}
     void accept(ast_visitor*) override;
 };
 
@@ -570,6 +578,7 @@ public:
     void set_iterator(iter_expr* node) {iterator = node;}
     void set_value(expr* node) {vector_node = node;}
     void set_code_block(code_block* node) {block = node;}
+    forei_loop_type get_type() const {return type;}
     iter_expr* get_iterator() {return iterator;}
     expr* get_value() {return vector_node;}
     code_block* get_code_block() {return block;}
diff --git a/ast/nasal_new_main.cpp b/ast/nasal_new_main.cpp
index 586243f..3f473b8 100644
--- a/ast/nasal_new_main.cpp
+++ b/ast/nasal_new_main.cpp
@@ -4,6 +4,7 @@
 #include "nasal_new_ast.h"
 #include "nasal_new_parse.h"
 #include "ast_visitor.h"
+#include "ast_dumper.h"
 
 #include <unordered_map>
 #include <thread>
@@ -86,15 +87,16 @@ void execute(
 
     // parser gets lexer's token list to compile
     parse.compile(lex).chkerr();
+    if (cmd&VM_AST) {
+        auto dumper = new ast_dumper();
+        dumper->visit_expr(parse.tree());
+    }
 
     // linker gets parser's ast and load import files to this ast
     // ld.link(parse, file, cmd&VM_DETAIL).chkerr();
 
     // optimizer does simple optimization on ast
     // optimize(parse.tree());
-    // if (cmd&VM_AST) {
-    //     parse.tree().dump();
-    // }
 
     // code generator gets parser's ast and import file list to generate code
     // gen.compile(parse, ld).chkerr();
diff --git a/ast/nasal_new_parse.cpp b/ast/nasal_new_parse.cpp
index 71bf125..00e3727 100644
--- a/ast/nasal_new_parse.cpp
+++ b/ast/nasal_new_parse.cpp
@@ -60,7 +60,7 @@ void parse::die(const span& loc, std::string info) {
     err.err("parse", loc, info);
 }
 
-void parse::match(tok type,const char* info) {
+void parse::match(tok type, const char* info) {
     if (!lookahead(type)) {
         if (info) {
             die(thisspan, info);
@@ -121,18 +121,10 @@ bool parse::check_func_end(expr* node) {
     auto type=node->get_type();
     if (type==expr_type::ast_func) {
         return true;
-    } else if (type==expr_type::ast_num ||
-        type==expr_type::ast_id ||
-        type==expr_type::ast_str ||
-        type==expr_type::ast_nil ||
-        type==expr_type::ast_vec ||
-        type==expr_type::ast_hash) {
-        return false;
-    }
-    if (type==expr_type::ast_def) {
-        return check_func_end(((definition_expr*)type)->get_value());
+    } else if (type==expr_type::ast_def) {
+        return check_func_end(((definition_expr*)node)->get_value());
     } else if (type==expr_type::ast_assign) {
-        return check_func_end(((assignment_expr*)type)->get_right());
+        return check_func_end(((assignment_expr*)node)->get_right());
     }
     return false;
 }
@@ -270,7 +262,7 @@ hash_pair* parse::pair() {
         match(tok::id, "expected hashmap key");
     }
     match(tok::colon);
-    node->set_element(calc());
+    node->set_value(calc());
     update_location(node);
     return node;
 }
@@ -408,7 +400,6 @@ expr* parse::calc() {
         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
         auto tmp = new assignment_expr(toks[ptr].loc);
         switch(toks[ptr].type) {
             case tok::eq: tmp->set_type(assignment_expr::assign_type::equal); break;
@@ -518,7 +509,6 @@ expr* parse::and_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
         auto tmp = new binary_operator(toks[ptr].loc);
         switch(toks[ptr].type) {
             case tok::cmpeq: tmp->set_type(binary_operator::binary_type::cmpeq); break;
@@ -760,7 +750,7 @@ expr* parse::definition() {
     return node;
 }
 
-multi_define* parse::incurve_def() {
+multi_identifier* parse::incurve_def() {
     const auto& loc=toks[ptr].loc;
     match(tok::lcurve);
     match(tok::var);
@@ -771,7 +761,7 @@ multi_define* parse::incurve_def() {
     return node;
 }
 
-multi_define* parse::outcurve_def() {
+multi_identifier* parse::outcurve_def() {
     const auto& loc=toks[ptr].loc;
     match(tok::lcurve);
     auto node = multi_id();
@@ -781,8 +771,8 @@ multi_define* parse::outcurve_def() {
     return node;
 }
 
-multi_define* parse::multi_id() {
-    auto node = new multi_define(toks[ptr].loc);
+multi_identifier* parse::multi_id() {
+    auto node = new multi_identifier(toks[ptr].loc);
     while(!lookahead(tok::eof)) {
         // only identifier is allowed here
         // but we check it at codegen stage
@@ -826,16 +816,16 @@ tuple_expr* parse::multi_scalar() {
 
 multi_assign* parse::multi_assignment() {
     auto node = new multi_assign(toks[ptr].loc);
-    node->set_left(multi_scalar());
+    node->set_tuple(multi_scalar());
     match(tok::eq);
     if (lookahead(tok::eof)) {
         die(thisspan, "expected value list");
         return node;
     }
     if (lookahead(tok::lcurve)) {
-        node->set_right(check_tuple()?multi_scalar():calc());
+        node->set_value(check_tuple()?multi_scalar():calc());
     } else {
-        node->set_right(calc());
+        node->set_value(calc());
     }
     update_location(node);
     return node;
@@ -845,10 +835,10 @@ expr* parse::loop() {
     ++in_loop;
     expr* node = nullptr;
     switch(toks[ptr].type) {
-        case tok::rwhile:  node=while_loop(); break;
-        case tok::rfor:    node=for_loop();   break;
+        case tok::rwhile:  node = while_loop(); break;
+        case tok::rfor:    node = for_loop();   break;
         case tok::forindex:
-        case tok::foreach: node=forei_loop(); break;
+        case tok::foreach: node = forei_loop(); break;
         default: break;
     }
     --in_loop;
@@ -870,6 +860,7 @@ for_expr* parse::for_loop() {
     auto node = new for_expr(toks[ptr].loc);
     match(tok::rfor);
     match(tok::lcurve);
+
     // first expression
     if (lookahead(tok::eof)) {
         die(thisspan, "expected definition");
@@ -884,6 +875,7 @@ for_expr* parse::for_loop() {
         node->set_initial(calc());
     }
     match(tok::semi, "expected ';' in for(;;)");
+
     // conditional expression
     if (lookahead(tok::eof)) {
         die(thisspan, "expected conditional expr");
@@ -894,6 +886,7 @@ for_expr* parse::for_loop() {
         node->set_condition(calc());
     }
     match(tok::semi, "expected ';' in for(;;)");
+
     //after loop expression
     if (lookahead(tok::eof)) {
         die(thisspan, "expected calculation");
@@ -1009,7 +1002,7 @@ break_expr* parse::break_expression() {
 return_expr* parse::return_expression() {
     auto node = new return_expr(toks[ptr].loc);
     match(tok::ret);
-    tok type=toks[ptr].type;
+    tok type = toks[ptr].type;
     if (type==tok::tknil || type==tok::num ||
         type==tok::str || type==tok::id ||
         type==tok::func || type==tok::sub ||
diff --git a/ast/nasal_new_parse.h b/ast/nasal_new_parse.h
index 72abdd1..98b736c 100644
--- a/ast/nasal_new_parse.h
+++ b/ast/nasal_new_parse.h
@@ -120,9 +120,9 @@ private:
     call_function* callf();
     slice_vector* subvec();
     expr* definition();
-    multi_define* incurve_def();
-    multi_define* outcurve_def();
-    multi_define* multi_id();
+    multi_identifier* incurve_def();
+    multi_identifier* outcurve_def();
+    multi_identifier* multi_id();
     tuple_expr* multi_scalar();
     multi_assign* multi_assignment();
     expr* loop();
diff --git a/makefile b/makefile
index 5dfa980..3cc1563 100644
--- a/makefile
+++ b/makefile
@@ -80,11 +80,12 @@ NASAL_NEW_AST=\
 	nasal_new_ast.o\
 	nasal_new_parse.o\
 	ast_visitor.o\
+	ast_dumper.o\
 	nasal_new_main.o
 
 # for test
-nasal_new: $(NASAL_NEW_AST)
-	$(CXX) $(NASAL_NEW_AST) -o nasal_new
+nnew: $(NASAL_NEW_AST)
+	$(CXX) $(NASAL_NEW_AST) -o nnew
 	@ echo "build done"
 
 nasal_new_main.o: ast/nasal_new_main.cpp
@@ -108,6 +109,9 @@ nasal_new_parse.o: ast/nasal_new_parse.h ast/nasal_new_parse.cpp ast/nasal_new_a
 ast_visitor.o: ast/nasal_new_ast.h ast/ast_visitor.h ast/ast_visitor.cpp
 	$(CXX) -std=$(STD) -c -O3 ast/ast_visitor.cpp -fno-exceptions -fPIC -o ast_visitor.o -I .
 
+ast_dumper.o: ast/nasal_new_ast.h ast/ast_visitor.h ast/ast_dumper.h ast/ast_dumper.cpp
+	$(CXX) -std=$(STD) -c -O3 ast/ast_dumper.cpp -fno-exceptions -fPIC -o ast_dumper.o -I .
+
 .PHONY: nasal_new_clean
 nasal_new_clean:
 	rm $(NASAL_NEW_AST)
\ No newline at end of file