diff --git a/lab.cpp b/lab.cpp
new file mode 100644
index 0000000..718e8a7
--- /dev/null
+++ b/lab.cpp
@@ -0,0 +1,35 @@
+#include <iostream>
+#include <fstream>
+#include <cstring>
+#include <thread>
+#include <cstdlib>
+#include "nasal.h"
+
+using namespace nasal;
+
+int main()
+{
+	std::cout<<">> input \"help\" to find help."<<std::endl;
+	std::string Command;
+	while(1)
+	{
+		std::cout<<">> ";
+		std::cin>>Command;
+		if(Command=="help")
+		{
+			std::cout<<">> 1.input file name to run the nasal script."<<std::endl;
+			std::cout<<">> 2.command cls to clear the screen."<<std::endl;
+			std::cout<<">> 3.command exit to shut down the program."<<std::endl;
+		}
+		else if(Command=="cls")
+			system("cls");
+		else if(Command=="exit")
+			break;
+		else
+		{
+			RunProcess(Command);
+			nasal_lexer.run();
+		}
+	}
+	return 0;
+}
diff --git a/nasal_func_stack.h b/nasal_func_stack.h
index ea75dde..a48d2a8 100644
--- a/nasal_func_stack.h
+++ b/nasal_func_stack.h
@@ -29,13 +29,18 @@ class func_stack
 		{
 			func_stack_unit *temp=head;
 			func_stack_unit *this_node=NULL;
-			while(temp->next)
+			if(head->next)
 			{
-				this_node=temp;
-				temp=temp->next;
-				delete this_node;
+				while(temp->next)
+				{
+					this_node=temp;
+					temp=temp->next;
+					delete this_node;
+				}
+				delete temp;
 			}
-			delete temp;
+			else
+				delete head;
 		}
 		void append_function(std::string &function_name,func &temp_func)
 		{
@@ -95,6 +100,22 @@ class func_stack
 			end_temp->next=NULL;
 			delete temp;
 		}
+		void delete_all()
+		{
+			func_stack_unit *temp=head->next;
+			func_stack_unit *this_node=NULL;
+			head->next=NULL;
+			if(!temp)
+				return;
+			while(temp->next)
+			{
+				this_node=temp;
+				temp=temp->next;
+				delete this_node;
+			}
+			delete temp;
+			return;
+		}
 };
 
 }
diff --git a/nasal_functional.h b/nasal_functional.h
index ad1816b..5365e7c 100644
--- a/nasal_functional.h
+++ b/nasal_functional.h
@@ -4,15 +4,78 @@
 #include <iostream>
 #include <cstring>
 
+#include "nasal_var_stack.h"
+#include "nasal_func_stack.h"
+
 namespace nasal
 {
 
+bool isFloat(std::string &str)
+{
+	for(int i=0;i<(int)str.length();++i)
+		if(str[i]=='.')
+			return true;
+	return false;
+}
+long long int int_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 0;
+		}
+	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;
+	}
+	return num;
+}
+double double_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 0;
+		}
+	int DotPlace=0;
+	for(int i=0;i<(int)str.length();++i)
+		if(str[i]=='.')
+		{
+			DotPlace=i;
+			break;
+		}
+	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;
+	}
+	return num;
+}
+
 #define FUNC_OPERATOR    1
 #define FUNC_IDENTIFIER  2
 #define FUNC_NUMBER      3
 #define FUNC_RESERVEWORD 4
 #define FUNC_STRING      5
 
+var_stack nasal_var_stack;
+func_stack nasal_func_stack;
+var temp_var;
+func temp_func;
+
 struct token_unit
 {
 	std::string type;
@@ -108,6 +171,7 @@ class token_list
 				std::cout<<"Running complete."<<std::endl;
 				return;
 			}
+			
 			while(temp->next)
 			{
 				temp=temp->next;
@@ -125,13 +189,162 @@ class token_list
 				}
 				else if(temp->type=="ReserveWord")
 				{
-					;
+					if(temp->content=="var")
+					{
+						if(temp->next)
+						{
+							temp=temp->next;
+							std::string name_of_var;
+							if(temp->type=="Identifier")
+								name_of_var=temp->content;
+							else
+							{
+								std::cout<<"line "<<temp->line<<": "<<"[Error] Missing identifier after \"var\"."<<std::endl;
+								return;
+							}
+							if(temp->next)
+							{
+								temp=temp->next;
+								if(temp->content=="=")
+								{
+									if(temp->next)
+									{
+										temp=temp->next;
+										if(temp->type=="Number")
+										{
+											temp_var.isGlobal=true;
+											if(isFloat(temp->content))
+											{
+												temp_var.Type="double";
+												temp_var.data=new double;
+												*((double *)temp_var.data)=double_Str2Num(temp->content);
+												nasal_var_stack.append_var(name_of_var,temp_var);
+												delete (double *)temp_var.data;
+												temp_var.data=NULL;
+											}
+											else
+											{
+												temp_var.Type="long long int";
+												temp_var.data=new long long int;
+												*((long long int *)temp_var.data)=int_Str2Num(temp->content);
+												nasal_var_stack.append_var(name_of_var,temp_var);
+												delete (long long int *)temp_var.data;
+												temp_var.data=NULL;
+											}
+										}
+										else if(temp->type=="String")
+										{
+											temp_var.isGlobal=true;
+											temp_var.Type="string";
+											temp_var.data=new std::string;
+											std::string temp_string="";
+											for(int i=1;i<(int)temp->content.length()-1;++i)
+												temp_string+=temp->content[i];
+											*((std::string *)temp_var.data)=temp_string;
+											nasal_var_stack.append_var(name_of_var,temp_var);
+											delete (std::string *)temp_var.data;
+											temp_var.data=NULL;
+										}
+										else if(temp->type=="Operator" && temp->content=="{")
+										{
+											bool make_pair=false;
+											int cnt=1;
+											while(temp->next)
+											{
+												temp=temp->next;
+												if(temp->type=="Operator" && temp->content=="}")
+												{
+													--cnt;
+													if(!cnt)
+													{
+														make_pair=true;
+														break;
+													}
+												}
+												else if(temp->type=="Operator" && temp->content=="{")
+													++cnt;
+											}
+											if(!make_pair)
+											{
+												std::cout<<"line "<<temp->line<<": "<<"[Error] Expect a \"}\"."<<std::endl;
+												return;
+											}
+										//end {
+										}
+										
+										if(!(temp->next && temp->next->content==";"))
+										{
+											std::cout<<"line "<<temp->line<<": "<<"[Error] Expect a \";\" at the end of the statement."<<std::endl;
+											nasal_var_stack.pop_var();
+											return; 
+										} 
+										else
+											temp=temp->next;
+									}
+									else
+									{
+										std::cout<<"line "<<temp->line<<": "<<"[Error] Missing value after operator = ."<<std::endl;
+										return;
+									}
+								}
+								else
+								{
+									std::cout<<"line "<<temp->line<<": "<<"[Error] Missing \"=\" after identifier."<<std::endl;
+									return;
+								}
+							//end operator
+							}
+							else
+							{
+								std::cout<<"line "<<temp->line<<": "<<"[Error] Missing elements after identifier."<<std::endl;
+								return;
+							}
+						//end identifier
+						}
+						else
+						{
+							std::cout<<"line "<<temp->line<<": "<<"[Error] Missing identifier after \"var\"."<<std::endl;
+							return;
+						}
+					//end var
+					}
+					else if(temp->content=="print")
+					{
+						if(temp->next && temp->next->content=="(")
+						{
+							temp=temp->next;
+							while(temp->next)
+							{
+								temp=temp->next;
+								if(temp->type=="String")
+								{
+									std::string temp_string="";
+									for(int i=1;i<(int)temp->content.length()-1;++i)
+										temp_string+=temp->content[i];
+									PrintString(temp_string);
+								}
+								else if(temp->type=="Identifier")
+									PrintVar(nasal_var_stack.SearchVar(temp->content));
+							}
+						}
+						else
+						{
+							std::cout<<"line "<<temp->line<<": "<<"[Error] Expect \"(\" after function print."<<std::endl;
+							return;
+						}
+					}
 				}
 				else if(temp->type=="String")
 				{
 					;
 				}
 			}
+			nasal_var_stack.print_var();
+			nasal_func_stack.print_function();
+			nasal_var_stack.delete_all();
+			nasal_func_stack.delete_all();
+			std::cout<<"Running complete."<<std::endl;
+			return;
 		}
 };
 
diff --git a/nasal_lexer.h b/nasal_lexer.h
index fa2a29d..bc0b898 100644
--- a/nasal_lexer.h
+++ b/nasal_lexer.h
@@ -7,6 +7,7 @@
 #include <cstring>
 #include "nasal_functional.h"
 
+
 namespace nasal
 {
 
@@ -241,32 +242,33 @@ void Scanner(int &Syn,const char Source[],std::string &token,int &ptr,int &line)
 	return;
 }
 
-token_list lexer;
+token_list nasal_lexer;
 
-void RunProcess(std::string &FileNameOrCommand)
+void RunProcess(std::string &FileName)
 {
 	int Syn=0;//token type
 	int Ptr=0;//pointer to one char in ResourcePrograme
 	int line=1;
 	std::string token;
+	nasal_lexer.delete_all();
 	
-	InputFile(FileNameOrCommand);
+	InputFile(FileName);
 	while(Syn!=SCANEND && Syn!=ERRORFOUND)
 	{
 		Scanner(Syn,ResourcePrograme,token,Ptr,line);
 		if(Syn==OPERATOR)
-			lexer.append("Operator",token,line);
+			nasal_lexer.append("Operator",token,line);
 		else if(Syn==IDENTIFIER)
-			lexer.append("Identifier",token,line);
+			nasal_lexer.append("Identifier",token,line);
 		else if(Syn==NUMBER)
-			lexer.append("Number",token,line);
+			nasal_lexer.append("Number",token,line);
 		else if(Syn==RESERVEWORD)
-			lexer.append("ReserveWord",token,line);
+			nasal_lexer.append("ReserveWord",token,line);
 		else if(Syn==STRING)
-			lexer.append("String",token,line);
+			nasal_lexer.append("String",token,line);
 	}
-	lexer.print();
-	std::cout<<">> Complete scanning \""<<FileNameOrCommand<<"\"."<<std::endl;
+	nasal_lexer.print();
+	std::cout<<">> Complete scanning \""<<FileName<<"\"."<<std::endl;
 	return;
 }
 
diff --git a/nasal_list.cpp b/nasal_list.cpp
index a9ace9b..6a34ea7 100644
--- a/nasal_list.cpp
+++ b/nasal_list.cpp
@@ -850,7 +850,7 @@ ListUnit NasalList::SearchElement(const int n)
 	return nil_list;
 }
 
-var::var(var &p)
+var::var(const var &p)
 {
 	Type=p.Type;
 	if(Type=="int")
diff --git a/nasal_list.h b/nasal_list.h
index e73d7ff..a6d11d9 100644
--- a/nasal_list.h
+++ b/nasal_list.h
@@ -49,7 +49,7 @@ class var
 		{
 			data=NULL;
 		}
-		var(var &);
+		var(const var &);
 		~var();
 		var& operator=(const var &);
 		void Print();
diff --git a/nasal_print.h b/nasal_print.h
index 8c6a07a..95b880c 100644
--- a/nasal_print.h
+++ b/nasal_print.h
@@ -8,37 +8,6 @@
 
 namespace nasal
 {
-	
-void PrintVar(var &Var)
-{
-	if(Var.Type=="int")
-		std::cout<<*((int *)Var.data);
-	else if(var.Type=="long long int")
-		std::cout<<*((long long int Var.data));
-	else if(Var.Type=="float")
-		std::cout<<*((float *)Var.data);
-	else if(Var.Type=="double")
-		std::cout<<*((double *)Var.data);
-	else if(Var.Type=="char")
-		std::cout<<*((char *)Var.data);
-	else if(Var.Type=="string")
-		std::cout<<*((std::string *)Var.data);
-	else if(Var.Type=="array")
-		((NasalList *)Var.data)->PrintList();
-	else if(Var.Type=="hash")
-		((NasalHash *)Var.data)->PrintHash();
-	else
-		std::cout<<"null";
-}
-void PrintVar(NasalHash &Var)
-{
-	Var.PrintHash();
-}
-void PrintVar(NasalList &Var)
-{
-	Var.PrintList();
-}
-
 
 void PrintString(std::string &PrintInfo)
 {
@@ -89,57 +58,27 @@ void PrintString(std::string &PrintInfo)
 	}
 	return;
 }
-/*
-void PrintString(const char *PrintInfo)
+void PrintVar(var Var)
 {
-	for(int i=0;i<strlen(PrintInfo);++i)
-	{
-		if(PrintInfo[i]=='\\' && i+1<strlen(PrintInfo))
-		{
-			switch(PrintInfo[i+1])
-			{
-				case 'n':
-					std::cout<<"\n";
-					++i;
-					break;
-				case 't':
-					std::cout<<"\t";
-					++i;
-					break;
-				case 'r':
-					std::cout<<"\r";
-					++i;
-					break;
-				case '\\':
-					std::cout<<"\\";
-					++i;
-					break;
-				case '\'':
-					std::cout<<"\'";
-					++i;
-					break;
-				case '\"':
-					std::cout<<"\"";
-					++i;
-					break;
-				default:
-					//error occurred
-					std::cout<<"[Error]: Incorrect escape character \'"<<PrintInfo[i]<<PrintInfo[i+1]<<"\' ."<<std::endl;
-					++i;
-					break;
-			}
-		}
-		else if(PrintInfo[i]=='\\' && i+1>=strlen(PrintInfo))
-		{
-			//error occurred
-			std::cout<<"[Error]: Missing character after \'\\\'"<<std::endl;
-		}
-		else
-			std::cout<<PrintInfo[i];
-	}
-	return;
+	if(Var.Type=="int")
+		std::cout<<*((int *)Var.data);
+	else if(Var.Type=="long long int")
+		std::cout<<*((long long int *)Var.data);
+	else if(Var.Type=="float")
+		std::cout<<*((float *)Var.data);
+	else if(Var.Type=="double")
+		std::cout<<*((double *)Var.data);
+	else if(Var.Type=="char")
+		std::cout<<*((char *)Var.data);
+	else if(Var.Type=="string")
+		PrintString(*((std::string *)Var.data));
+	else if(Var.Type=="array")
+		((NasalList *)Var.data)->PrintList();
+	else if(Var.Type=="hash")
+		((NasalHash *)Var.data)->PrintHash();
+	else
+		std::cout<<"null";
 }
-*/
 
 }
 
diff --git a/nasal_var_stack.h b/nasal_var_stack.h
index 793e32a..6ea83b0 100644
--- a/nasal_var_stack.h
+++ b/nasal_var_stack.h
@@ -30,13 +30,18 @@ class var_stack
 		{
 			var_stack_unit *temp=head;
 			var_stack_unit *this_node=NULL;
-			while(temp->next)
+			if(head->next)
 			{
-				this_node=temp;
-				temp=temp->next;
-				delete this_node;
+				while(temp->next)
+				{
+					this_node=temp;
+					temp=temp->next;
+					delete this_node;
+				}
+				delete temp;
 			}
-			delete temp;
+			else
+				delete head;
 		}
 		void append_var(std::string &varia_name,var &temp_var)
 		{
@@ -55,16 +60,16 @@ class var_stack
 			while(temp->next)
 			{
 				temp=temp->next;
-				std::cout<<"["<<temp->var_detail.Type<<"]: "<<temp->var_name;
-				PrintVar(temp->var_detail);
-				std::cout<<endl;
+				std::cout<<"["<<temp->var_detail.Type<<"]: "<<temp->var_name<<" : ";
+				if(temp->var_detail.Type!="string")
+					PrintVar(temp->var_detail);
+				else
+					std::cout<<*((std::string *)temp->var_detail.data);
+				std::cout<<std::endl;
 			}
-			std::cout<<"["<<temp->var_detail.Type<<"]: "<<temp->var_name;
-			PrintVar(temp->var_detail);
-			std::cout<<endl;
 			return;
 		}
-		var &SearchVar(std::string varia_name)
+		var SearchVar(std::string varia_name)
 		{
 			var temp_var;
 			temp_var.data=NULL;
@@ -93,6 +98,22 @@ class var_stack
 			end_temp->next=NULL;
 			delete temp;
 		}
+		void delete_all()
+		{
+			var_stack_unit *temp=head->next;
+			var_stack_unit *this_node=NULL;
+			head->next=NULL;
+			if(!temp)
+				return;
+			while(temp->next)
+			{
+				this_node=temp;
+				temp=temp->next;
+				delete this_node;
+			}
+			delete temp;
+			return;
+		}
 };
 
 }