diff --git a/misc/lexer(useless).h b/misc/lexer(useless).h
new file mode 100644
index 0000000..d5cb091
--- /dev/null
+++ b/misc/lexer(useless).h
@@ -0,0 +1,183 @@
+#ifndef __LEXER_H__
+#define __LEXER_H__
+
+
+#include <iostream>
+#include <fstream>
+#include <cstring>
+#include "nasal.h"
+#include "process_stack.h"
+
+using namespace nasal;
+
+std::string text;
+process_stack _test;
+process_stack_unit _unit;
+
+void PrintProcess(std::string content)
+{
+	std::string Sentence="";
+	int len=(int)content.length();
+	for(int i=0;i<len;++i)
+	{
+		if(content[i]==',')
+			Sentence="";
+		else if(content[i]=='\"')//string mode
+		{
+			Sentence="";
+			for(int j=i+1;j<len;++j)
+			{
+				if(content[j]=='\\' && j+1<len)
+				{
+					Sentence+=content[j];
+					Sentence+=content[j+1];
+					++j;
+				}
+				else if(content[j]=='\"')
+				{
+					i=j;
+					break;
+				}
+				else
+					Sentence+=content[j];
+			}
+			PrintString(Sentence);
+		}
+		else if(content[i]!=' ' && content[i]!='\"' && content[i]!=',')//check var
+		{
+			Sentence="";
+			for(int j=i;j<len;++j)
+			{
+				if(content[j]!=' ' && content[j]!='\"' && content[j]!=',')
+					Sentence+=content[j];
+				if(content[j]==',' || content[j]==' ' || j==len-1)
+				{
+					i=j;
+					break;
+				}
+			}
+			if(_test.check_stack(Sentence))
+			{
+				_test.stack_content_print(Sentence);
+			}
+			else
+				std::cout<<std::endl<<"[Error] "<<Sentence<<" is not declared in this scope."<<std::endl;
+		}
+	}
+	std::cout<<std::endl;
+	return;
+}
+
+void FileProcess(const char *FileName)
+{
+	std::ifstream fin(FileName);
+	
+	fin.close();
+	return;
+}
+
+void CommandProcess()
+{
+	while(1)
+	{
+		std::cout<<">> ";
+		std::getline(std::cin,text);
+		int len=(int)text.length();
+		
+		int sharpDetected=0;
+		for(int i=len-1;i>=0;--i)
+		{
+			if(text[i]=='#')
+			{
+				//ignore sharp
+				len=i;
+				sharpDetected=i;
+			}
+			if(text[i]==';')
+			{
+				len=i+1;
+				//find the real end of the sentence
+				if(sharpDetected)
+				{
+					for(int j=sharpDetected-1;j>=len;--j)
+						if(text[j]!=' ')
+						{
+							len=j+1;
+							break;
+						}
+				}
+				else
+				{
+					for(int j=(int)text.length()-1;j>=len;--j)
+						if(text[j]!=' ')
+						{
+							len=j+1;
+							break;
+						}
+				}
+				break;
+			}
+		}
+		
+		if(text[len-1]==';')
+		{
+			for(int i=0;i<len;++i)
+			{
+				if(text[i]=='p' && i+1<len && text[i+1]=='r' && i+2<len && text[i+2]=='i' && i+3<len && text[i+3]=='n' && i+4<len && text[i+4]=='t')
+				{
+					//In this part every error leads to an error information and breaks the loop!
+					
+					//check the first char after print is '(' or not
+					int string_beg=len-1;
+					for(int j=i+5;j<len;++j)
+						if(text[j]!=' ')
+						{
+							string_beg=j;
+							break;
+						}
+						
+					if(text[string_beg]!='(')
+					{
+						std::cout<<std::endl<<"[Error] Missing \'(\' ."<<std::endl;
+						break;
+					}
+					
+					//check the ')' and the place 
+					int string_end=len-1;
+					for(int j=len-2;j>=0;--j)
+						if(text[j]!=' ')
+						{
+							string_end=j;
+							break;
+						}
+					if(text[string_end]!=')')
+					{
+						std::cout<<std::endl<<"[Error] Missing \')\' ."<<std::endl;
+						break;
+					}
+					
+					std::string content="";
+					for(int j=string_beg+1;j<string_end;++j)
+						content+=text[j];
+					
+					std::cout<<std::endl<<"Target string: "<<content<<std::endl;
+					PrintProcess(content);
+					break;
+				}
+				else if(text[i]=='v' && i+1<len && text[i+1]=='a' && i+2<len && text[i+2]=='r')
+				{
+					;
+				}
+				else if(i==len-1)
+					std::cout<<std::endl<<"[Error] Incorrect command."<<std::endl;
+			}
+		}
+		else
+		{
+			std::cout<<std::endl<<"[Error] Expected \';\' after this line."<<std::endl;
+		}
+	}
+	return;
+}
+
+#endif
diff --git a/misc/lexical_analysis.cpp b/misc/lexical_analysis.cpp
new file mode 100644
index 0000000..cf16fa7
--- /dev/null
+++ b/misc/lexical_analysis.cpp
@@ -0,0 +1,291 @@
+#include <iostream>
+#include <fstream>
+#include <cstring>
+
+#define IDENTIFIER  -1 //自定义标识符 
+#define OPERATOR    -2 //界符 or 运算符 
+#define NUMBER      -3 //数字 
+#define RESERVEWORD -4 //关键字 
+#define STRING      -5 //字符串类型 
+#define FAIL        -6 //失败 
+#define SCANEND     -7 //扫描完成 
+#define ERRORFOUND  -8 //异常错误 
+
+// \n 换行 
+// \t tab
+// \r 回车 
+// \\ 反斜线 
+// \' 单引号 
+// \" 双引号 
+std::string ReserveWord[26]=
+{
+	"for","foreach","forindex","while",
+	"var","func","break","continue","return",
+	"if","else","elsif","nil","and","or",
+	"print","cmp","append","setsize","subvec","pop",
+	"sort","contains","delete","keys","typeof"
+};
+
+std::string OperatorOrDelimiter[40]=
+{
+	"+","-","*","/","=","+=","-=","*=","/=",
+	"\n","\t","\r","\\","\'","\"",".",
+	"<","<=",">",">=","==","!=","~=","!","~",
+	",",";","(",")","[","]","{","}","#","?",":",
+	"&","|","%","^"
+};
+
+std::string IdentifierTable[1000]={""};
+char ResourcePrograme[16777216];
+
+int isReserveWord(std::string &p)
+{
+	for(int i=0;i<26;++i)
+		if(ReserveWord[i]==p)
+			return i+1;
+	return FAIL;
+}
+
+int isOperatorOrDelimiter(std::string &p)
+{
+	for(int i=0;i<40;++i)
+		if(OperatorOrDelimiter[i]==p)
+			return i+1;
+	return FAIL;
+}
+
+bool isLetter(char t)
+{
+	return (('a'<=t) && (t<='z') || ('A'<=t) && (t<='Z'));
+}
+
+bool isNumber(char t)
+{
+	return (('0'<=t) && (t<='9'));
+}
+
+void InputFile(std::string &FileName)
+{
+	std::ifstream fin(FileName);
+	if(fin.fail())
+	{
+		std::cout<<"[Error] Failed to load file: "<<FileName<<std::endl;
+		ResourcePrograme[0]='@';
+		fin.close();
+		return;
+	}
+	int i=0;
+	bool FindNote=false;
+	while(!fin.eof())
+	{
+		ResourcePrograme[i]=fin.get();
+		if(ResourcePrograme[i]=='\n')
+			FindNote=false;
+		if(ResourcePrograme[i]!='#' && !FindNote)
+			++i;
+		else if(ResourcePrograme[i]=='#')
+		{
+			FindNote=true;
+		}
+		if(fin.eof())
+			break;
+	}
+	ResourcePrograme[i]='@';
+	++i;
+	for(int j=0;j<i;++j)
+		std::cout<<ResourcePrograme[j];
+	std::cout<<std::endl;
+	fin.close();
+	return;
+}
+
+void Scanner(int &Syn,const char Source[],std::string &token,int &ptr)
+{
+	char temp;
+	temp=Source[ptr];
+	while(temp==' ' || temp=='\n' || temp=='\t' || temp=='\r' || temp<0 || temp>127)
+	{
+		++ptr;
+		temp=Source[ptr];
+	}
+	
+	token="";
+	if(isLetter(temp) || temp=='_')
+	{
+		token+=temp;
+		++ptr;
+		temp=Source[ptr];
+		while(isLetter(temp) || isNumber(temp) || temp=='_')
+		{
+			token+=temp;
+			++ptr;
+			temp=Source[ptr];
+		}
+		Syn=isReserveWord(token);
+		if(Syn==FAIL)
+			Syn=IDENTIFIER;
+		else
+			Syn=RESERVEWORD;
+	}
+	else if(isNumber(temp))
+	{
+		int PointCnt=0;
+		while(isNumber(temp))
+		{
+			token+=temp;
+			++ptr;
+			temp=Source[ptr];
+			if(temp=='.' && !PointCnt)
+			{
+				++PointCnt;
+				token+=temp;
+				++ptr;
+				temp=Source[ptr];
+			}
+		}
+		Syn=NUMBER;
+	}
+	else if(temp=='(' || temp==')' || temp=='[' || temp==']' || temp=='{' ||
+			temp=='}' || temp==',' || temp==';' || temp=='|' || temp==':' ||
+			temp=='?' || temp=='.' || temp=='`' || temp=='\'' || temp=='&'||
+			temp=='%' || temp=='$' || temp=='^')
+	{
+		token+=temp;
+		++ptr;
+		Syn=OPERATOR;
+	}
+	else if(temp=='=' || temp=='+' || temp=='-' || temp=='*' || temp=='!' || temp=='/' || temp=='<' || temp=='>' || temp=='~')
+	{
+		Syn=OPERATOR;
+		token+=temp;
+		++ptr;
+		temp=Source[ptr];
+		if(temp=='=')
+		{
+			token+=temp;
+			++ptr;
+		}
+	}
+	else if(temp=='\\')
+	{
+		Syn=OPERATOR;
+		token+=temp;
+		++ptr;
+		temp=Source[ptr];
+		if(temp=='=' || temp=='n' || temp=='t' || temp=='r' || temp=='\\' || temp=='\'' || temp=='\"')
+		{
+			token+=temp;
+			++ptr;
+		}
+	}
+	else if(temp=='\"')
+	{
+		Syn=STRING;
+		token+=temp;
+		++ptr;
+		temp=Source[ptr];
+		while(temp!='\"')
+		{
+			if(temp=='\\')
+			{
+				token+=temp;
+				
+				++ptr;
+				temp=Source[ptr];
+				token+=temp;
+				
+				++ptr;
+				temp=Source[ptr];
+			}
+			else
+			{
+				token+=temp;
+				++ptr;
+				temp=Source[ptr];
+			}
+			if(temp=='@' || temp=='\n')
+				break;
+		}
+		//add the last char \"
+		if(temp=='\"')
+		{
+			token+=temp;
+			++ptr;
+		}
+		else
+			token+=" __missing_end_of_string";
+	}
+	else if(temp=='@')
+	{
+		Syn=SCANEND;
+		return;
+	}
+	else
+	{
+		Syn=FAIL;
+		std::cout<<"[Error] Unexpected error occurred: "<<temp<<std::endl;
+		system("pause");
+		++ptr;
+		return;
+	}
+	if(token=="")
+	{
+		Syn=ERRORFOUND;
+		std::cout<<"[Error] Cannot identify "<<std::endl;
+	}
+	return;
+}
+
+void help()
+{
+	std::cout<<">> exit: exit the programe."<<std::endl;
+	std::cout<<">> clear: clean the screen."<<std::endl;
+	std::cout<<">> help: find help."<<std::endl;
+	std::cout<<">> input the file name to scan."<<std::endl;
+}
+
+int main()
+{
+	help();
+	while(1)
+	{
+		int Syn=0;//token type
+		int Ptr=0;//pointer to one char in ResourcePrograme
+		std::string token;
+		std::string FileNameOrCommand;
+		std::cout<<">> ";
+		std::cin>>FileNameOrCommand;
+		
+		if(FileNameOrCommand=="exit")
+			break;
+		else if(FileNameOrCommand=="clear")
+		{
+			system("cls");
+			continue;
+		}
+		else if(FileNameOrCommand=="help")
+		{
+			help();
+			continue;
+		}
+		//std::ofstream fout("Data.txt");
+		InputFile(FileNameOrCommand);
+		while(Syn!=SCANEND && Syn!=ERRORFOUND)
+		{
+			Scanner(Syn,ResourcePrograme,token,Ptr);
+			if(Syn==OPERATOR)
+				std::cout<<"( Operator    | "<<token<<" )"<<std::endl;
+			else if(Syn==IDENTIFIER)
+				std::cout<<"( Identifier  | "<<token<<" )"<<std::endl;
+			else if(Syn==NUMBER)
+				std::cout<<"( Number      | "<<token<<" )"<<std::endl;
+			else if(Syn==RESERVEWORD)
+				std::cout<<"( ReserveWord | "<<token<<" )"<<std::endl;
+			else if(Syn==STRING)
+				std::cout<<"( String      | "<<token<<" )"<<std::endl;
+		}
+		std::cout<<">> Complete scanning \""<<FileNameOrCommand<<"\"."<<std::endl;
+		//fout.close();
+	}
+	return 0;
+}
diff --git a/misc/process_stack.h b/misc/process_stack.h
new file mode 100644
index 0000000..a8960f8
--- /dev/null
+++ b/misc/process_stack.h
@@ -0,0 +1,159 @@
+#ifndef __PROCESS_STACK_H__
+#define __PROCESS_STACK_H__
+
+#include <iostream>
+#include <cstring>
+#include "nasal.h"
+namespace nasal
+{
+
+
+struct process_stack_unit
+{
+	int line;                  //place the unit first appear
+	std::string name;          //content of the unit or name of the var/class/function
+	std::string format_type;   //var class function string info
+	var unitdata;
+	bool global;
+	process_stack_unit *next;
+	process_stack_unit *last;
+};
+
+class process_stack
+{
+	private:
+		process_stack_unit *head;
+		process_stack_unit *ptr;
+	public:
+		process_stack()
+		{
+			head=new process_stack_unit;
+			head->line=0;
+			head->name="InterpreterInfo";
+			head->format_type="Info";
+			head->global=false;
+			head->unitdata.Type="string";
+			head->unitdata.data=new std::string;
+			*((std::string *)head->unitdata.data)="# Nasal language for FlightGear.";
+			
+			head->last=NULL;
+			head->next=NULL;
+			ptr=NULL;
+		}
+		~process_stack()
+		{
+			process_stack_unit *temp=head;
+			while(temp->next)
+			{
+				temp=temp->next;
+				delete head;
+				head=temp;
+			}
+			delete head;
+		}
+		void stack_append(process_stack_unit &p)
+		{
+			process_stack_unit *temp=head;
+			process_stack_unit *last_node;
+			while(temp->next)
+			{
+				temp=temp->next;
+			}
+			temp->next=new process_stack_unit;
+			
+			last_node=temp;
+			temp=temp->next;
+			
+			temp->last=last_node;
+			last_node->next=temp;
+			temp->next=NULL;
+			
+			temp->name=p.name;
+			temp->line=p.line;
+			temp->format_type=p.format_type;
+			temp->global=p.global;
+			temp->unitdata=p.unitdata;
+			
+			return;
+		}
+		void stack_print(bool reverse_mode_used)
+		{
+			process_stack_unit *temp=head;
+			std::cout<<"In stack: "<<std::endl;
+			if(reverse_mode_used)
+			{
+				while(temp->next)
+					temp=temp->next;
+				while(temp->last)
+				{
+					std::cout<<"line "<<temp->line<<": |"<<temp->format_type<<"|"<<temp->name<<"|\n\t|";
+					temp->unitdata.Print();
+					std::cout<<std::endl;
+					temp=temp->last;
+				}
+				std::cout<<"line "<<temp->line<<": |"<<temp->format_type<<"|"<<temp->name<<"|\n\t|";
+				temp->unitdata.Print();
+				std::cout<<std::endl;
+			}
+			else
+			{
+				std::cout<<"line "<<temp->line<<": |"<<temp->format_type<<"|"<<temp->name<<"|\n\t|";
+				temp->unitdata.Print();
+				std::cout<<std::endl;
+				while(temp->next)
+				{
+					temp=temp->next;
+					std::cout<<"line "<<temp->line<<": |"<<temp->format_type<<"|"<<temp->name<<"|\n\t|";
+					temp->unitdata.Print();
+					std::cout<<std::endl;
+				}
+			}
+			std::cout<<"End."<<std::endl;
+			return;
+		}
+		void pop()
+		{
+			process_stack_unit *temp=head;
+			process_stack_unit *last_node;
+			while(temp->next)
+			{
+				last_node=temp;
+				temp=temp->next;
+			}
+			last_node->next=NULL;
+			delete temp;
+			return;
+		}
+		bool check_stack(std::string &ElementName)
+		{
+			process_stack_unit *temp=head;
+			while(temp->next)
+			{
+				temp=temp->next;
+				if(temp->name==ElementName)
+					return true;
+			}
+			return false;
+		}
+		void stack_content_print(std::string &ElementName)
+		{
+			process_stack_unit *temp=head;
+			while(temp->next)
+			{
+				temp=temp->next;
+				if(temp->name==ElementName)
+				{
+					temp->unitdata.Print();
+					return;
+				}
+			}
+			return;
+		}
+};
+
+
+
+
+}
+
+#endif
diff --git a/misc/str2num.h b/misc/str2num.h
new file mode 100644
index 0000000..6f86c8c
--- /dev/null
+++ b/misc/str2num.h
@@ -0,0 +1,60 @@
+#ifndef __STR2NUM_H__
+#define __STR2NUM_H__
+
+#include <iostream>
+#include <cstring>
+
+namespace nasal
+{
+
+void Str2Num(std::string &str)
+{
+	for(int i=0;i<(int)str.length();++i)
+		if(!(('0'<=str[i]) && (str[i]<='9') || (str[i]=='.')))
+		{
+			std::cout<<"[Error] Non-numeric string."<<std::endl;
+			return;
+		}
+	
+	bool isFloat=false;
+	int DotPlace=0;
+	for(int i=0;i<(int)str.length();++i)
+		if(str[i]=='.')
+		{
+			isFloat=true;
+			DotPlace=i;
+			break;
+		}
+	if(!isFloat)
+	{
+		long long int num=0;
+		long long int acc=1;
+		for(int i=(int)str.length()-1;i>=0;--i)
+		{
+			num+=acc*((long long int)(str[i]-'0'));
+			acc*=10;
+		}
+		std::cout<<num<<std::endl;
+	}
+	else
+	{
+		double num=0;
+		double acc=1;
+		double aff=0.1;
+		for(int i=DotPlace+1;i<(int)str.length();++i)
+		{
+			num+=aff*((double)(str[i]-'0'));
+			aff*=0.1;
+		}
+		for(int i=DotPlace-1;i>=0;--i)
+		{
+			num+=acc*((double)(str[i]-'0'));
+			acc*=10;
+		}
+		std::cout<<num<<std::endl;
+	}
+	return;
+}
+
+}
+#endif