diff --git a/balloon/abstract_syntax_tree.h b/balloon/abstract_syntax_tree.h
index f30e243..0a3c789 100644
--- a/balloon/abstract_syntax_tree.h
+++ b/balloon/abstract_syntax_tree.h
@@ -5,29 +5,185 @@ class abstract_syntax_tree
 {
 	private:
 		int type;
-		double number;
-		std::string str;
-		std::string name;
+		double var_number;
+		std::string var_string;
+		std::string var_name;
 		std::list<abstract_syntax_tree> children;
 	public:
 		abstract_syntax_tree()
 		{
-			type=__null_node;
-			number=0;
-			str="";
-			name="";
+			type=0;
+			var_number=0;
+			var_string="";
+			var_name="";
 			children.clear();
 			return;
 		}
 		abstract_syntax_tree(const abstract_syntax_tree& p)
 		{
 			type=p.type;
-			number=p.number;
-			str=p.str;
-			name=p.name;
+			var_number=p.var_number;
+			var_string=p.var_string;
+			var_name=p.var_name;
 			children=p.children;
 			return;
 		}
+		abstract_syntax_tree& operator=(const abstract_syntax_tree& p)
+		{
+			type=p.type;
+			var_number=p.var_number;
+			var_string=p.var_string;
+			var_name=p.var_name;
+			children.clear();
+			children=p.children;
+			return *this;
+		}
+		void set_clear()
+		{
+			type=0;
+			var_number=0;
+			var_string="";
+			var_name="";
+			children.clear();
+			return;
+		}
+		void print_tree(const int n)
+		{
+			std::string str="";
+			for(int i=0;i<n;++i)
+				str+="| ";
+			std::cout<<str;
+			print_detail_token(type);
+			switch(type)
+			{
+				case __number:std::cout<<": "<<var_number;break;
+				case __string:std::cout<<": "<<var_string;break;
+				case __id:
+				case __call_array:
+				case __call_hash:
+				case __call_function:std::cout<<": "<<var_name;break;
+			}
+			std::cout<<std::endl;
+			if(!children.empty())
+			{
+				for(auto i=children.begin();i!=children.end();++i)
+					i->print_tree(n+1);
+			}
+			return;
+		}
+		void set_type(const int _type)
+		{
+			type=_type;
+			return;
+		}
+		void set_string(std::string str)
+		{
+			var_string=str;
+			return;
+		}
+		void set_number(std::string str)
+		{
+			if(str=="nil")
+			{
+				var_number=0;
+				return;
+			}
+			if((int)str.length()>2 && (str[1]=='x' || str[1]=='o'))
+			{
+				if(str[1]=='x')
+				{
+					int num=0;
+					int pw=1;
+					for(int i=(int)str.length()-1;i>1;--i)
+					{
+						if('0'<=str[i] && str[i]<='9')
+							num+=(str[i]-'0')*pw;
+						else if('a'<=str[i] && str[i]<='f')
+							num+=(10+str[i]-'a')*pw;
+						else if('A'<=str[i] && str[i]<='F')
+							num+=(10+str[i]-'A')*pw;
+						pw<<=4;
+					}
+					var_number=(double)num;
+				}
+				else
+				{
+					int num=0;
+					int pw=1;
+					for(int i=(int)str.length()-1;i>1;--i)
+					{
+						num+=(str[i]-'0')*pw;
+						pw<<=3;
+					}
+					var_number=(double)num;
+				}
+				return;
+			}
+			int dot_place=-1;
+			for(int i=0;i<(int)str.length();++i)
+				if(str[i]=='.')
+				{
+					dot_place=i;
+					break;
+				}
+			if(dot_place==-1)
+			{
+				var_number=0;
+				double pw=1;
+				for(int i=(int)str.length()-1;i>=0;--i)
+				{
+					var_number+=(str[i]-'0')*pw;
+					pw*=10;
+				}
+			}
+			else
+			{
+				var_number=0;
+				double pw=0.1;
+				for(int i=dot_place+1;i<(int)str.length();++i)
+				{
+					var_number+=(str[i]-'0')*pw;
+					pw/=10;
+				}
+				pw=1;
+				for(int i=dot_place-1;i>=0;--i)
+				{
+					var_number+=(str[i]-'0')*pw;
+					pw*=10;
+				}
+			}
+			return;
+		}
+		void set_name(std::string& str)
+		{
+			var_name=str;
+			return;
+		}
+		void add_child(abstract_syntax_tree p)
+		{
+			children.push_back(p);
+			return;
+		}
+		int get_type()
+		{
+			return type;
+		}
+		double get_number()
+		{
+			return var_number;
+		}
+		std::string get_string()
+		{
+			return var_string;
+		}
+		std::string get_name()
+		{
+			return var_name;
+		}
+		std::list<abstract_syntax_tree>& get_children()
+		{
+			return children;
+		}
 };
 
 #endif
diff --git a/balloon/balloon_lexer.h b/balloon/balloon_lexer.h
index 7ce7b39..d509693 100644
--- a/balloon/balloon_lexer.h
+++ b/balloon/balloon_lexer.h
@@ -14,7 +14,54 @@ int is_reserve_word(std::string str)
 			return __reserve_word;
 	return __token_identifier;
 }
-
+bool check_number(std::string str)
+{
+	if(str.length()==1)
+		return true;
+	else if(str.length()==2 && '0'<str[0] && str[0]<='9' && '0'<=str[1] && str[1]<='9')
+		return true;
+	else if(str.length()>=3 && str[0]=='0' && str[1]=='x')
+	{
+		for(int i=2;i<str.length();++i)
+		{
+			if('0'<=str[i] && str[i]<='9' || 'a'<=str[i] && str[i]<='f' || 'A'<=str[i] && str[i]<='F')
+				;
+			else
+				return false;
+		}
+		return true;
+	}
+	else if(str.length()>=3 && str[0]=='0' && str[1]=='o')
+	{
+		for(int i=2;i<str.length();++i)
+		{
+			if('0'<=str[i] && str[i]<='7')
+				;
+			else
+				return false;
+		}
+		return true;
+	}
+	else
+	{
+		int dotcnt=0;
+		for(int i=0;i<str.length();++i)
+		{
+			if(str[i]=='.')
+				++dotcnt;
+			else if(!('0'<=str[i] && str[i]<='9'))
+				return false;
+		}
+		if(dotcnt>1)
+			return false;
+		if(str[0]=='.')
+			return false;
+		if(!dotcnt && str[0]=='0')
+			return false;
+		return true;
+	}
+	return false;
+}
 
 
 class resource_file
@@ -30,6 +77,11 @@ class resource_file
 		void input_file(std::string filename)
 		{
 			std::ifstream fin(filename,std::ios::binary);
+			if(fin.fail())
+			{
+				std::cout<<">>[Resource] cannot find a file named \'"<<filename<<"\' ."<<std::endl;
+				return;
+			}
 			char c;
 			while(!fin.eof())
 			{
@@ -164,13 +216,19 @@ class balloon_lexer
 				else if('0'<=*ptr && *ptr<='9')
 				{
 					token_str="";
-					while(('0'<=*ptr && *ptr<='9') || *ptr=='.' || *ptr=='x' || *ptr=='o')
+					while(('0'<=*ptr && *ptr<='9') || ('a'<=*ptr && *ptr<='f') || ('A'<=*ptr && *ptr<='F') || *ptr=='.' || *ptr=='x' || *ptr=='o')
 					{
 						token_str+=*ptr;
 						++ptr;
 						if(ptr==res.end())
 							break;
 					}
+					if(!check_number(token_str))
+					{
+						++error;
+						std::cout<<">>[Lexer-error] line "<<line<<": error number "<<token_str<<"."<<std::endl;
+						token_str="0";
+					}
 					token new_token;
 					new_token.line=line;
 					new_token.type=__token_number;
@@ -261,6 +319,7 @@ class balloon_lexer
 						break;
 				}
 			}
+			std::cout<<">>[Lexer] complete scanning. "<<error<<" error(s)."<<std::endl;
 			return;
 		}
 		void generate_detail_token()
@@ -404,11 +463,16 @@ class balloon_lexer
 					detail_token.push_back(detail);
 				}
 			}
+			std::cout<<">>[Lexer] complete generating. "<<error<<" error(s)."<<std::endl;
 			return;
 		}
 		std::list<token>& get_detail_token()
 		{
 			return detail_token;
 		}
+		int get_error()
+		{
+			return error;
+		}
 };
 #endif
diff --git a/balloon/balloon_parse.h b/balloon/balloon_parse.h
index 9b2b0fc..1532387 100644
--- a/balloon/balloon_parse.h
+++ b/balloon/balloon_parse.h
@@ -4,17 +4,17 @@
 class balloon_parse
 {
 	private:
-		std::stack<token> detail;
+		std::stack<token> parse;
 		token this_token;
 		int error;
 		int warning;
 	public:
 		void get_token()
 		{
-			if(!detail.empty())
+			if(!parse.empty())
 			{
-				this_token=detail.top();
-				detail.pop();
+				this_token=parse.top();
+				parse.pop();
 			}
 			else
 				this_token.type=0;
@@ -22,16 +22,48 @@ class balloon_parse
 		}
 		void get_detail_token_stream(std::list<token>& tk_list)
 		{
+			while(!parse.empty())
+				parse.pop();
+			if(tk_list.empty())
+				return;
 			std::stack<token> temp;
 			for(std::list<token>::iterator i=tk_list.begin();i!=tk_list.end();++i)
 				temp.push(*i);
 			while(!temp.empty())
 			{
-				detail.push(temp.top());
+				parse.push(temp.top());
 				temp.pop();
 			}
 			return;
 		}
+		void print_parse_stack()
+		{
+			if(parse.empty())
+				return;
+			std::stack<token> temp;
+			int line=parse.top().line;
+			std::cout<<line<<"	";
+			while(!parse.empty())
+			{
+				if(parse.top().line!=line)
+				{
+					line=parse.top().line;
+					std::cout<<std::endl<<line<<"	";
+				}
+				temp.push(parse.top());
+				std::cout<<" ";
+				print_detail_token(temp.top().type);
+				parse.pop();
+			}
+			while(!temp.empty())
+			{
+				parse.push(temp.top());
+				temp.pop();
+			}
+			std::cout<<std::endl;
+			return;
+		}
+		
 };
 
 #endif
diff --git a/balloon/balloon_var.h b/balloon/balloon_var.h
index 97c1a9a..decac0c 100644
--- a/balloon/balloon_var.h
+++ b/balloon/balloon_var.h
@@ -39,7 +39,7 @@ class var
 			balloon_hash=p.balloon_hash;
 			return;
 		}
-		var& operator=(const var p)
+		var& operator=(const var& p)
 		{
 			type=p.type;
 			number=p.number;
diff --git a/balloon/main.cpp b/balloon/main.cpp
index 99a7f6e..c19177f 100644
--- a/balloon/main.cpp
+++ b/balloon/main.cpp
@@ -3,6 +3,7 @@ int main()
 {
 	resource_file prog;
 	balloon_lexer lex;
+	balloon_parse pas;
 	std::string command;
 	std::cout<<">> Balloon interpreter by ValKmjolnir"<<std::endl;
 	std::cout<<">> Input [help] to find help."<<std::endl;
@@ -49,10 +50,25 @@ int main()
 		{
 			lex.scanner(prog.get_resource());
 			lex.generate_detail_token();
+			if(!lex.get_error())
+			{
+				pas.get_detail_token_stream(lex.get_detail_token());
+				pas.print_parse_stack();
+			}
+			else
+				std::cout<<">>[Lexer] error(s) found,stop."<<std::endl;
 		}
 		else if(command=="ast")
 		{
-			;
+			lex.scanner(prog.get_resource());
+			lex.generate_detail_token();
+			if(!lex.get_error())
+			{
+				pas.get_detail_token_stream(lex.get_detail_token());
+				
+			}
+			else
+				std::cout<<">>[Lexer] error(s) found,stop."<<std::endl;
 		}
 		else if(command=="run")
 		{