diff --git a/.gitignore b/.gitignore
index 76f7285..b3a00de 100644
--- a/.gitignore
+++ b/.gitignore
@@ -50,7 +50,9 @@ cmake-windows-*
 *.out
 *.app
 nasal
+nasal-format
 nasal.exe
+nasal-format.exe
 
 # Visual Studio specific
 *.sln
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1cb6a3f..a04118e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -41,6 +41,7 @@ set(NASAL_OBJECT_SOURCE_FILE
     ${CMAKE_SOURCE_DIR}/src/util/fs.cpp
     ${CMAKE_SOURCE_DIR}/src/util/util.cpp
     ${CMAKE_SOURCE_DIR}/src/ast_dumper.cpp
+    ${CMAKE_SOURCE_DIR}/src/ast_format.cpp
     ${CMAKE_SOURCE_DIR}/src/ast_visitor.cpp
     ${CMAKE_SOURCE_DIR}/src/nasal_ast.cpp
     ${CMAKE_SOURCE_DIR}/src/nasal_codegen.cpp
@@ -62,12 +63,18 @@ target_include_directories(nasal-object PRIVATE ${CMAKE_SOURCE_DIR}/src)
 add_executable(nasal ${CMAKE_SOURCE_DIR}/src/main.cpp)
 target_link_libraries(nasal nasal-object)
 
+# build nasal-format
+add_executable(nasal-format ${CMAKE_SOURCE_DIR}/src/format.cpp)
+target_link_libraries(nasal-format nasal-object)
+
 # link ldl and lpthread
 if(NOT CMAKE_HOST_SYSTEM_NAME MATCHES "Windows")
     target_link_libraries(nasal dl)
     target_link_libraries(nasal pthread)
+    target_link_libraries(nasal-format pthread)
 endif()
 target_include_directories(nasal PRIVATE ${CMAKE_SOURCE_DIR}/src)
+target_include_directories(nasal-format PRIVATE ${CMAKE_SOURCE_DIR}/src)
 
 # copy nasal from build dir to the outside dir
 if(NOT CMAKE_HOST_SYSTEM_NAME MATCHES "Windows")
@@ -77,6 +84,12 @@ if(NOT CMAKE_HOST_SYSTEM_NAME MATCHES "Windows")
                 ${CMAKE_SOURCE_DIR}/build/nasal
                 ${CMAKE_SOURCE_DIR}/nasal
     )
+    add_custom_command(
+        TARGET nasal-format POST_BUILD
+        COMMAND ${CMAKE_COMMAND} -E copy
+                ${CMAKE_SOURCE_DIR}/build/nasal-format
+                ${CMAKE_SOURCE_DIR}/nasal-format
+    )
 endif()
 
 # build module
diff --git a/src/ast_dumper.h b/src/ast_dumper.h
index 1586d0b..e8c5565 100644
--- a/src/ast_dumper.h
+++ b/src/ast_dumper.h
@@ -38,7 +38,7 @@ private:
         if (indent.size() && indent.back()=="│  ") {
             indent.back() = "├──";
         }
-        for(const auto& i : indent) {
+        for (const auto& i : indent) {
             std::cout << i;
         }
     }
diff --git a/src/ast_format.cpp b/src/ast_format.cpp
new file mode 100644
index 0000000..f50b822
--- /dev/null
+++ b/src/ast_format.cpp
@@ -0,0 +1,412 @@
+#include "ast_format.h"
+#include "util/util.h"
+
+#include <iostream>
+
+namespace nasal {
+
+bool ast_format::visit_use_stmt(use_stmt* node) {
+    dump_formating_node_info(node, "use statement");
+    out << "use ";
+    for(auto i : node->get_path()) {
+        i->accept(this);
+        if (i != node->get_path().back()) {
+            out << ".";
+        }
+    }
+    return true;
+}
+
+bool ast_format::visit_null_expr(null_expr* node) {
+    dump_formating_node_info(node, "null expression");
+    out << "null";
+    return true;
+}
+
+bool ast_format::visit_nil_expr(nil_expr* node) {
+    dump_formating_node_info(node, "nil expression");
+    out << "nil";
+    return true;
+}
+
+bool ast_format::visit_number_literal(number_literal* node) {
+    dump_formating_node_info(node, "number expression");
+    out << node->get_number();
+    return true;
+}
+
+bool ast_format::visit_string_literal(string_literal* node) {
+    dump_formating_node_info(node, "string expression");
+    out << "\"" << util::rawstr(node->get_content()) << "\"";
+    return true;
+}
+
+bool ast_format::visit_identifier(identifier* node) {
+    dump_formating_node_info(node, "identifier");
+    out << node->get_name();
+    return true;
+}
+
+bool ast_format::visit_bool_literal(bool_literal* node) {
+    dump_formating_node_info(node, "bool expression");
+    out << (node->get_flag()? "true" : "false");
+    return true;
+}
+
+bool ast_format::visit_vector_expr(vector_expr* node) {
+    dump_formating_node_info(node, "vector expression");
+    out << "[";
+    for(auto i : node->get_elements()) {
+        i->accept(this);
+        if (i != node->get_elements().back()) {
+            out << ", ";
+        }
+    }
+    out << "]";
+    return true;
+}
+
+bool ast_format::visit_hash_expr(hash_expr* node) {
+    dump_formating_node_info(node, "hash expression");
+    out << "{";
+    for(auto i : node->get_members()) {
+        i->accept(this);
+        if (i != node->get_members().back()) {
+            out << ", ";
+        }
+    }
+    out << "}";
+    return true;
+}
+
+bool ast_format::visit_hash_pair(hash_pair* node) {
+    dump_formating_node_info(node, "hash pair");
+    out << node->get_name();
+    if (node->get_value()) {
+        out << " : ";
+        node->get_value()->accept(this);
+    }
+    return true;
+}
+
+bool ast_format::visit_function(function* node) {
+    dump_formating_node_info(node, "function");
+    out << "func(";
+    for(auto i : node->get_parameter_list()) {
+        i->accept(this);
+        if (i != node->get_parameter_list().back()) {
+            out << ", ";
+        }
+    }
+    out << ") ";
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_format::visit_code_block(code_block* node) {
+    dump_formating_node_info(node, "code block");
+    out << "{\n";
+    push_indent();
+    for(auto i : node->get_expressions()) {
+        dump_indent();
+        i->accept(this);
+        if (need_dump_semi(i)) {
+            out << ";\n";
+        } else {
+            out << "\n";
+        }
+    }
+    pop_indent();
+    dump_indent();
+    out << "}";
+    return true;
+}
+
+bool ast_format::visit_parameter(parameter* node) {
+    dump_formating_node_info(node, "parameter");
+    out << node->get_parameter_name();
+    switch (node->get_parameter_type()) {
+        case parameter::kind::normal_parameter: break;
+        case parameter::kind::dynamic_parameter: out << "..."; break;
+        case parameter::kind::default_parameter: out << " = "; break;
+    }
+    if (node->get_default_value()) {
+        node->get_default_value()->accept(this);
+    }
+    return true;
+}
+
+bool ast_format::visit_ternary_operator(ternary_operator* node) {
+    dump_formating_node_info(node, "ternary operator");
+    node->get_condition()->accept(this);
+    out << " ? ";
+    node->get_left()->accept(this);
+    out << " : ";
+    node->get_right()->accept(this);
+    return true;
+}
+
+bool ast_format::visit_binary_operator(binary_operator* node) {
+    dump_formating_node_info(node, "binary operator");
+    out << "(";
+    node->get_left()->accept(this);
+    switch(node->get_operator_type()) {
+        case binary_operator::kind::add: out << " + "; break;
+        case binary_operator::kind::sub: out << " - "; break;
+        case binary_operator::kind::mult: out << " * "; break;
+        case binary_operator::kind::div: out << " / "; break;
+        case binary_operator::kind::concat: out << " ~ "; break;
+        case binary_operator::kind::bitwise_and: out << " & "; break;
+        case binary_operator::kind::bitwise_or: out << " | "; break;
+        case binary_operator::kind::bitwise_xor: out << " ^ "; break;
+        case binary_operator::kind::cmpeq: out << " == "; break;
+        case binary_operator::kind::cmpneq: out << " != "; break;
+        case binary_operator::kind::grt: out << " > "; break;
+        case binary_operator::kind::geq: out << " >= "; break;
+        case binary_operator::kind::less: out << " < "; break;
+        case binary_operator::kind::leq: out << " <= "; break;
+        case binary_operator::kind::condition_and: out << " and "; break;
+        case binary_operator::kind::condition_or: out << " or "; break;
+        case binary_operator::kind::null_chain: out << " ?? "; break;
+    }
+    node->get_right()->accept(this);
+    out << ")";
+    return true;
+}
+
+bool ast_format::visit_unary_operator(unary_operator* node) {
+    dump_formating_node_info(node, "unary operator");
+    switch(node->get_operator_type()) {
+        case unary_operator::kind::negative: out << "-"; break;
+        case unary_operator::kind::logical_not: out << "!"; break;
+        case unary_operator::kind::bitwise_not: out << "~"; break;
+    }
+    node->get_value()->accept(this);
+    return true;
+}
+
+bool ast_format::visit_call_expr(call_expr* node) {
+    dump_formating_node_info(node, "call expression");
+    node->get_first()->accept(this);
+    for(auto i : node->get_calls()) {
+        i->accept(this);
+    }
+    return true;
+}
+
+bool ast_format::visit_call_hash(call_hash* node) {
+    dump_formating_node_info(node, "call hash");
+    out << "." << node->get_field();
+    return true;
+}
+
+bool ast_format::visit_null_access(null_access* node) {
+    dump_formating_node_info(node, "null access operator(?.)");
+    out << "?." << node->get_field();
+    return true;
+}
+
+bool ast_format::visit_call_vector(call_vector* node) {
+    dump_formating_node_info(node, "call vector");
+    out << "[";
+    for(auto i : node->get_slices()) {
+        i->accept(this);
+        if (i != node->get_slices().back()) {
+            out << ", ";
+        }
+    }
+    out << "]";
+    return true;
+}
+
+bool ast_format::visit_call_function(call_function* node) {
+    dump_formating_node_info(node, "call function");
+    out << "(";
+    for(auto i : node->get_argument()) {
+        i->accept(this);
+        if (i != node->get_argument().back()) {
+            out << ", ";
+        }
+    }
+    out << ")";
+    return true;
+}
+
+bool ast_format::visit_slice_vector(slice_vector* node) {
+    dump_formating_node_info(node, "slice vector");
+    node->get_begin()->accept(this);
+    if (node->get_end()) {
+        out << " : ";
+        node->get_end()->accept(this);
+    }
+    return true;
+}
+
+bool ast_format::visit_definition_expr(definition_expr* node) {
+    dump_formating_node_info(node, "definition");
+    out << "var ";
+    if (node->get_variable_name()) {
+        node->get_variable_name()->accept(this);
+    } else {
+        node->get_variables()->accept(this);
+    }
+    out << " = ";
+    if (node->get_tuple()) {
+        node->get_tuple()->accept(this);
+    } else {
+        node->get_value()->accept(this);
+    }
+    return true;
+}
+
+bool ast_format::visit_assignment_expr(assignment_expr* node) {
+    dump_formating_node_info(node, "assignment");
+    node->get_left()->accept(this);
+    switch(node->get_assignment_type()) {
+        case assignment_expr::kind::add_equal: out << " += "; break;
+        case assignment_expr::kind::sub_equal: out << " -= "; break;
+        case assignment_expr::kind::mult_equal: out << " *= "; break;
+        case assignment_expr::kind::div_equal: out << " /= "; break;
+        case assignment_expr::kind::concat_equal: out << " ~= "; break;
+        case assignment_expr::kind::equal: out << " = "; break;
+        case assignment_expr::kind::bitwise_and_equal: out << " &= "; break;
+        case assignment_expr::kind::bitwise_or_equal: out << " |= "; break;
+        case assignment_expr::kind::bitwise_xor_equal: out << " ^= "; break;
+    }
+    node->get_right()->accept(this);
+    return true;
+}
+
+bool ast_format::visit_multi_identifier(multi_identifier* node) {
+    dump_formating_node_info(node, "multi identifier");
+    out << "(";
+    for(auto i : node->get_variables()) {
+        i->accept(this);
+        if (i != node->get_variables().back()) {
+            out << ", ";
+        }
+    }
+    out << ")";
+    return true;
+}
+
+bool ast_format::visit_tuple_expr(tuple_expr* node) {
+    dump_formating_node_info(node, "tuple expression");
+    out << "(";
+    for(auto i : node->get_elements()) {
+        i->accept(this);
+        if (i != node->get_elements().back()) {
+            out << ", ";
+        }
+    }
+    out << ")";
+    return true;
+}
+
+bool ast_format::visit_multi_assign(multi_assign* node) {
+    dump_formating_node_info(node, "multi assign");
+    node->get_tuple()->accept(this);
+    out << " = ";
+    node->get_value()->accept(this);
+    return true;
+}
+
+bool ast_format::visit_while_expr(while_expr* node) {
+    dump_formating_node_info(node, "while statement");
+    out << "while (";
+    node->get_condition()->accept(this);
+    out << ") ";
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_format::visit_for_expr(for_expr* node) {
+    dump_formating_node_info(node, "for statement");
+    out << "for (";
+    node->get_initial()->accept(this);
+    out << "; ";
+    node->get_condition()->accept(this);
+    out << "; ";
+    node->get_step()->accept(this);
+    out << ") ";
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_format::visit_iter_expr(iter_expr* node) {
+    dump_formating_node_info(node, "iteration expression");
+    if (node->is_definition()) {
+        out << "var ";
+    }
+    if (node->get_name()) {
+        node->get_name()->accept(this);
+    } else {
+        node->get_call()->accept(this);
+    }
+    return true;
+}
+
+bool ast_format::visit_forei_expr(forei_expr* node) {
+    dump_formating_node_info(node, "forindex/foreach statement");
+    if (node->get_loop_type()==forei_expr::kind::foreach) {
+        out << "foreach ";
+    } else {
+        out << "forindex ";
+    }
+    out << "(";
+    node->get_iterator()->accept(this);
+    out << "; ";
+    node->get_value()->accept(this);
+    out << ") ";
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_format::visit_condition_expr(condition_expr* node) {
+    dump_formating_node_info(node, "condition statement");
+    out << "if ";
+    node->get_if_statement()->accept(this);
+    for (auto i : node->get_elsif_stataments()) {
+        out << " elsif ";
+        i->accept(this);
+    }
+    if (node->get_else_statement()) {
+        out << " else ";
+        node->get_else_statement()->accept(this);
+    }
+    return true;
+}
+
+bool ast_format::visit_if_expr(if_expr* node) {
+    dump_formating_node_info(node, "if statement");
+    if (node->get_condition()) {
+        out << "(";
+        node->get_condition()->accept(this);
+        out << ") ";
+    }
+    node->get_code_block()->accept(this);
+    return true;
+}
+
+bool ast_format::visit_continue_expr(continue_expr* node) {
+    dump_formating_node_info(node, "continue statement");
+    out << "continue";
+    return true;
+}
+
+bool ast_format::visit_break_expr(break_expr* node) {
+    dump_formating_node_info(node, "break statement");
+    out << "break";
+    return true;
+}
+
+bool ast_format::visit_return_expr(return_expr* node) {
+    dump_formating_node_info(node, "return statement");
+    out << "return ";
+    if (node->get_value()) {
+        node->get_value()->accept(this);
+    }
+    return true;
+}
+
+}
diff --git a/src/ast_format.h b/src/ast_format.h
new file mode 100644
index 0000000..8f3b23c
--- /dev/null
+++ b/src/ast_format.h
@@ -0,0 +1,144 @@
+#pragma once
+
+#include "ast_visitor.h"
+
+#include <iostream>
+#include <iomanip>
+#include <fstream>
+#include <cstring>
+#include <sstream>
+#include <vector>
+
+namespace nasal {
+
+class ast_format: public ast_visitor {
+private:
+    std::ofstream out;
+    std::vector<std::string> indent;
+
+private:
+    void push_indent() {
+        indent.push_back("  ");
+    }
+    void pop_indent() {
+        if (indent.size()) {
+            indent.pop_back();
+        }
+    }
+    void dump_indent() {
+        for (const auto& i : indent) {
+            out << i;
+        }
+    }
+    void dump_formating_node_info(expr* n, const char* name) {
+        std::cout << "  formating " << name << " @ 0x";
+        std::cout << std::hex << n << std::dec << "\n";
+    }
+    bool need_dump_semi(expr* n) {
+        switch (n->get_type()) {
+            case expr_type::ast_use:
+            case expr_type::ast_null:
+            case expr_type::ast_nil:
+            case expr_type::ast_num:
+            case expr_type::ast_str:
+            case expr_type::ast_bool:
+            case expr_type::ast_vec:
+            case expr_type::ast_hash:
+            case expr_type::ast_call: return true;
+            case expr_type::ast_def: {
+                auto dn = reinterpret_cast<definition_expr*>(n);
+                if (dn->get_value() &&
+                    dn->get_value()->get_type() == expr_type::ast_func) {
+                    return false;
+                }
+                return true;
+            }
+            case expr_type::ast_assign: {
+                auto dn = reinterpret_cast<assignment_expr*>(n);
+                if (dn->get_right() &&
+                    dn->get_right()->get_type() == expr_type::ast_func) {
+                    return false;
+                }
+                return true;
+            }
+            case expr_type::ast_ret: {
+                auto dn = reinterpret_cast<return_expr*>(n);
+                if (dn->get_value() &&
+                    dn->get_value()->get_type() == expr_type::ast_func) {
+                    return false;
+                }
+                return true;
+            }
+            default: break;
+        }
+
+        return false;
+    }
+
+public:
+    bool visit_use_stmt(use_stmt*) 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_null_access(null_access*) 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;
+
+public:
+    ast_format(const std::string output_file): out(output_file) {
+        if (out.fail()) {
+            throw std::runtime_error("can't open file: " + output_file);
+        }
+    }
+
+    void do_format(code_block* root) {
+        std::cout << "nasal-format is not stable right now, ";
+        std::cout << "take care of source code!\n";
+        dump_formating_node_info(root, "program root");
+        bool is_use_statement = true;
+        for (auto i : root->get_expressions()) {
+            if (is_use_statement && i->get_type() != expr_type::ast_use) {
+                is_use_statement = false;
+                out << "\n";
+            }
+
+            i->accept(this);
+            if (need_dump_semi(i)) {
+                out << ";\n";
+            } else {
+                out << "\n";
+            }
+        }
+    }
+};
+
+}
diff --git a/src/cli/cli.cpp b/src/cli/cli.cpp
index 8605fa1..9961467 100644
--- a/src/cli/cli.cpp
+++ b/src/cli/cli.cpp
@@ -1,6 +1,12 @@
+#include "nasal.h"
 #include "cli/cli.h"
+#include "util/util.h"
+#include "nasal_parse.h"
 
 #include <iostream>
+#include <thread>
+#include <cstdlib>
+#include <ctime>
 
 namespace nasal::cli {
 
@@ -59,4 +65,75 @@ std::ostream& help(std::ostream& out) {
     return out;
 }
 
+std::ostream& nasal_format_help(std::ostream& out) {
+    out
+    << "\n"
+    << "     ,--#-,\n"
+    << "<3  / \\____\\  <3\n"
+    << "    |_|__A_|\n"
+    << "\nnasal-format <option>\n"
+    << "option:\n"
+    << "   -h,   --help     | get help.\n"
+    << "   -v,   --version  | get version.\n"
+    << "\nnasal-format <file>\n"
+    << "file:\n"
+    << "   <filename>       | file to be formatted.\n"
+    << "\n";
+    return out;
+}
+
+std::ostream& logo(std::ostream& out) {
+    out
+    << "\n"
+    << "       __                _\n"
+    << "    /\\ \\ \\__ _ ___  __ _| |\n"
+    << "   /  \\/ / _` / __|/ _` | |\n"
+    << "  / /\\  / (_| \\__ \\ (_| | |\n"
+    << "  \\_\\ \\/ \\__,_|___/\\__,_|_|\n"
+    << "\n"
+    << "ver  : " << __nasver__
+    << " " << nasal::util::get_platform()
+    << " " << nasal::util::get_arch()
+    << " (" << __DATE__ << " " << __TIME__ << ")\n"
+    << "std  : c++ " << __cplusplus << "\n"
+    << "core : " << std::thread::hardware_concurrency() << " core(s)\n"
+    << "repo : https://github.com/ValKmjolnir/Nasal-Interpreter\n"
+    << "repo : https://gitee.com/valkmjolnir/Nasal-Interpreter\n"
+    << "wiki : https://wiki.flightgear.org/Nasal_scripting_language\n"
+    << "\n"
+    << "presented by fgprc members:\n"
+    << " - http://fgprc.org\n"
+    << " - http://fgprc.org.cn\n"
+    << "\n"
+    << "input <nasal-format -h> to get help.\n\n";
+    return out;
+}
+
+std::ostream& version(std::ostream& out) {
+    std::srand(static_cast<u32>(std::time(nullptr)));
+
+    f64 num = 0;
+    for(u32 i = 0; i<5; ++i) {
+        num = (num+rand())*(1.0/(RAND_MAX+1.0));
+    }
+    // give you 5% to see this easter egg
+    if (num<0.05) {
+        nasal::parse::easter_egg();
+    }
+
+    out << "nasal version " << __nasver__;
+    out << " " << nasal::util::get_platform();
+    out << " " << nasal::util::get_arch();
+    out << " (" << __DATE__ << " " << __TIME__ << ")\n";
+    return out;
+}
+
+std::ostream& nasal_format_version(std::ostream& out) {
+    out << "nasal-format version " << __nasver__ << "-beta";
+    out << " " << nasal::util::get_platform();
+    out << " " << nasal::util::get_arch();
+    out << " (" << __DATE__ << " " << __TIME__ << ")\n";
+    return out;
+}
+
 }
\ No newline at end of file
diff --git a/src/cli/cli.h b/src/cli/cli.h
index 1b070aa..bbbfe52 100644
--- a/src/cli/cli.h
+++ b/src/cli/cli.h
@@ -69,5 +69,10 @@ const std::unordered_map<std::string, option> cli_options = {
 cli_config parse(const std::vector<std::string>&);
 
 std::ostream& help(std::ostream&);
+std::ostream& nasal_format_help(std::ostream&);
+
+std::ostream& logo(std::ostream&);
+std::ostream& version(std::ostream&);
+std::ostream& nasal_format_version(std::ostream&);
 
 }
\ No newline at end of file
diff --git a/src/format.cpp b/src/format.cpp
new file mode 100644
index 0000000..755ab83
--- /dev/null
+++ b/src/format.cpp
@@ -0,0 +1,56 @@
+#include "nasal.h"
+#include "nasal_lexer.h"
+#include "nasal_ast.h"
+#include "nasal_parse.h"
+#include "util/util.h"
+#include "cli/cli.h"
+#include "ast_format.h"
+
+#include <iostream>
+#include <thread>
+
+[[noreturn]]
+void err() {
+    std::cerr << "invalid argument(s), use <nasal-format -h> to get help.\n";
+    std::exit(1);
+}
+
+void execute(const nasal::cli::cli_config& config) {
+    nasal::lexer lex;
+    nasal::parse parse;
+
+    // lexer scans file to get tokens
+    lex.scan(config.input_file_path).chkerr();
+
+    // parser gets lexer's token list to compile
+    parse.compile(lex).chkerr();
+
+    nasal::ast_format("nasal-format-out.nas").do_format(parse.tree());
+}
+
+int main(i32 argc, const char* argv[]) {
+    // output version info
+    if (argc <= 1) {
+        err();
+    } else if (argc > 2) {
+        err();
+    }
+
+    // the first argument is the executable itself, ignore it
+    const auto config = nasal::cli::parse({argv+1, argv+argc});
+
+    // run directly or show help
+    if (argc == 2) {
+        if (config.has(nasal::cli::option::cli_help)) {
+            std::clog << nasal::cli::nasal_format_help;
+        } else if (config.has(nasal::cli::option::cli_version)) {
+            std::clog << nasal::cli::nasal_format_version;
+        } else if (config.input_file_path.size()) {
+            execute(config);
+        } else {
+            err();
+        }
+        return 0;
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/src/main.cpp b/src/main.cpp
index 3e0a4ea..24b1419 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -18,55 +18,8 @@
 #include "repl/repl.h"
 #include "cli/cli.h"
 
-#include <thread>
 #include <cstdlib>
 
-std::ostream& logo(std::ostream& out) {
-    out
-    << "\n"
-    << "       __                _\n"
-    << "    /\\ \\ \\__ _ ___  __ _| |\n"
-    << "   /  \\/ / _` / __|/ _` | |\n"
-    << "  / /\\  / (_| \\__ \\ (_| | |\n"
-    << "  \\_\\ \\/ \\__,_|___/\\__,_|_|\n"
-    << "\n"
-    << "ver  : " << __nasver__
-    << " " << nasal::util::get_platform()
-    << " " << nasal::util::get_arch()
-    << " (" << __DATE__ << " " << __TIME__ << ")\n"
-    << "std  : c++ " << __cplusplus << "\n"
-    << "core : " << std::thread::hardware_concurrency() << " core(s)\n"
-    << "repo : https://github.com/ValKmjolnir/Nasal-Interpreter\n"
-    << "repo : https://gitee.com/valkmjolnir/Nasal-Interpreter\n"
-    << "wiki : https://wiki.flightgear.org/Nasal_scripting_language\n"
-    << "\n"
-    << "presented by fgprc members:\n"
-    << " - http://fgprc.org\n"
-    << " - http://fgprc.org.cn\n"
-    << "\n"
-    << "input <nasal -h> to get help.\n\n";
-    return out;
-}
-
-std::ostream& version(std::ostream& out) {
-    std::srand(static_cast<u32>(std::time(nullptr)));
-
-    f64 num = 0;
-    for(u32 i = 0; i<5; ++i) {
-        num = (num+rand())*(1.0/(RAND_MAX+1.0));
-    }
-    // give you 5% to see this easter egg
-    if (num<0.05) {
-        nasal::parse::easter_egg();
-    }
-
-    out << "nasal version " << __nasver__;
-    out << " " << nasal::util::get_platform();
-    out << " " << nasal::util::get_arch();
-    out << " (" << __DATE__ << " " << __TIME__ << ")\n";
-    return out;
-}
-
 [[noreturn]]
 void err() {
     std::cerr << "invalid argument(s), use <nasal -h> to get help.\n";
@@ -157,8 +110,8 @@ void execute(const nasal::cli::cli_config& config) {
 
 i32 main(i32 argc, const char* argv[]) {
     // output version info
-    if (argc<=1) {
-        std::clog << logo;
+    if (argc <= 1) {
+        std::clog << nasal::cli::logo;
         return 0;
     }
 
@@ -166,11 +119,11 @@ i32 main(i32 argc, const char* argv[]) {
     const auto config = nasal::cli::parse({argv+1, argv+argc});
 
     // run directly or show help
-    if (argc==2) {
+    if (argc == 2) {
         if (config.has(nasal::cli::option::cli_help)) {
             std::clog << nasal::cli::help;
         } else if (config.has(nasal::cli::option::cli_version)) {
-            std::clog << version;
+            std::clog << nasal::cli::version;
         } else if (config.has(nasal::cli::option::cli_repl_mode)) {
             auto repl = std::make_unique<nasal::repl::repl>();
             repl->execute();