diff --git a/process_stack.h b/process_stack.h
deleted file mode 100644
index a8960f8..0000000
--- a/process_stack.h
+++ /dev/null
@@ -1,159 +0,0 @@
-#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