diff --git a/balloon/abstract_syntax_tree.cpp b/balloon/abstract_syntax_tree.cpp
new file mode 100644
index 0000000..c4fef75
--- /dev/null
+++ b/balloon/abstract_syntax_tree.cpp
@@ -0,0 +1,65 @@
+#ifndef __ABSTRACT_SYNTAX_TREE_CPP__
+#define __ABSTRACT_SYNTAX_TREE_CPP__
+
+balloon_scope global;
+var abstract_syntax_tree::get_value()
+{
+	var temp;
+	temp.set_type(type);
+	if(type==__number)
+		temp.set_number(number);
+	else if(type==__string)
+		temp.set_string(str);
+	else if(type==__array)
+	{
+		var new_var;
+	}
+	else if(type==__hash)
+	{
+		var new_var;
+	}
+	else if(type==__function)
+		temp.set_function(*this);
+	if(name.length()!=0)
+		temp.set_name(name);
+	return temp;
+}
+void abstract_syntax_tree::run_root()
+{
+	global.set_clear();
+	int beg_time,end_time;
+	int exit_type=__process_exited_successfully;
+	beg_time=time(NULL);
+	for(std::list<abstract_syntax_tree>::iterator i=children.begin();i!=children.end();++i)
+	{
+		if(i->type==__definition)
+		{
+			var new_var;
+			std::list<abstract_syntax_tree>::iterator j=i->children.begin();
+			std::string _name=j->name;
+			if(!global.search_var(_name))
+			{
+				new_var.set_name(_name);
+				global.add_var(new_var);
+			}
+			else
+			{
+				std::cout<<">>[Runtime-error] redeclaration of \'"<<_name<<"\'."<<std::endl;
+				exit_type=__redeclaration;
+				break;
+			}
+		}
+	}
+	end_time=time(NULL);
+	std::cout<<">>[Runtime] process exited after "<<end_time-beg_time<<" sec(s) with returned state \'";
+	print_exit_type(exit_type);
+	std::cout<<"\'."<<std::endl;
+	return;
+}
+
+
+		
+
+		
+
+#endif
diff --git a/balloon/abstract_syntax_tree.h b/balloon/abstract_syntax_tree.h
index 5313ec9..f4f34ab 100644
--- a/balloon/abstract_syntax_tree.h
+++ b/balloon/abstract_syntax_tree.h
@@ -1,9 +1,11 @@
 #ifndef __ABSTRACT_SYNTAX_TREE_H__
 #define __ABSTRACT_SYNTAX_TREE_H__
 
+class var;
+
 class abstract_syntax_tree
 {
-	private:
+	protected:
 		int type;
 		double number;
 		std::string str;
@@ -189,6 +191,8 @@ class abstract_syntax_tree
 		{
 			return children;
 		}
+		var get_value();
+		void run_root();
 };
 
 #endif
diff --git a/balloon/balloon.h b/balloon/balloon.h
index 3ce757c..ad4e6bc 100644
--- a/balloon/balloon.h
+++ b/balloon/balloon.h
@@ -6,11 +6,15 @@
 #include <fstream>
 #include <list>
 #include <stack>
+#include <ctime>
 
 #include "balloon_type.h"
 #include "abstract_syntax_tree.h"
 #include "balloon_var.h"
 #include "balloon_lexer.h"
 #include "balloon_parse.h"
+#include "balloon_scope.h"
+
+#include "abstract_syntax_tree.cpp"
 
 #endif
diff --git a/balloon/balloon_parse.h b/balloon/balloon_parse.h
index 4da62d3..86e5422 100644
--- a/balloon/balloon_parse.h
+++ b/balloon/balloon_parse.h
@@ -75,6 +75,12 @@ class balloon_parse
 			root.print_tree(1);
 			return;
 		}
+		void run_tree()
+		{
+			std::cout<<">>[Runtime] process begins at addr:"<<(void*)(&root)<<"."<<std::endl;
+			root.run_root();
+			return;
+		}
 		abstract_syntax_tree ret();
 		abstract_syntax_tree choose();
 		abstract_syntax_tree loop();
diff --git a/balloon/balloon_scope.h b/balloon/balloon_scope.h
new file mode 100644
index 0000000..1a320a4
--- /dev/null
+++ b/balloon/balloon_scope.h
@@ -0,0 +1,37 @@
+#ifndef __BALLOON_SCOPE_H__
+#define __BALLOON_SCOPE_H__
+
+class balloon_scope
+{
+	private:
+		std::list<var> scope;
+		var error_var;
+	public:
+		void set_clear()
+		{
+			scope.clear();
+			return;
+		}
+		bool search_var(std::string name)
+		{
+			for(std::list<var>::iterator i=scope.begin();i!=scope.end();++i)
+				if(i->get_name()==name)
+					return true;
+			return false;
+		}
+		void add_var(var t)
+		{
+			scope.push_back(t);
+			return;
+		}
+		var& get_var(std::string name)
+		{
+			for(std::list<var>::iterator i=scope.begin();i!=scope.end();++i)
+				if(i->get_name()==name)
+					return *i;
+			std::cout<<">>[Runtime-error] \'"<<name<<"\' was not declared in this scope."<<std::endl;
+			return error_var;
+		}
+};
+
+#endif
diff --git a/balloon/balloon_type.h b/balloon/balloon_type.h
index 446c473..5463ce5 100644
--- a/balloon/balloon_type.h
+++ b/balloon/balloon_type.h
@@ -138,5 +138,23 @@ void print_detail_token(int type)
 	return;
 }
 
+enum runtime_error_type
+{
+	__process_exited_successfully,
+	__redeclaration
+};
+
+void print_exit_type(int type)
+{
+	std::string context;
+	switch(type)
+	{
+		case __process_exited_successfully: context="success";break;
+		case __redeclaration:               context="redeclare";break;
+		default:                            context="unknown";break;
+	}
+	std::cout<<context;
+	return;
+}
 
 #endif
diff --git a/balloon/balloon_var.h b/balloon/balloon_var.h
index 7aa2953..1391d2f 100644
--- a/balloon/balloon_var.h
+++ b/balloon/balloon_var.h
@@ -56,6 +56,7 @@ class var
 		void set_name(std::string);
 		void set_number(double);
 		void set_string(std::string);
+		void set_function(abstract_syntax_tree&);
 		void append_array(var);
 		void append_hash(var);
 		std::string get_name();
@@ -63,6 +64,7 @@ class var
 		std::string get_string();
 		var& get_array_member(int);
 		var& get_hash_member(std::string);
+		abstract_syntax_tree& get_function();
 };
 
 var error_var;
@@ -86,6 +88,11 @@ void var::set_string(std::string _str)
 	str=_str;
 	return;
 }
+void var::set_function(abstract_syntax_tree& p)
+{
+	function=p;
+	return;
+}
 void var::append_array(var _new_var)
 {
 	balloon_array.push_back(_new_var);
@@ -130,4 +137,8 @@ var& var::get_hash_member(std::string _name)
 	std::cout<<">>[Runtime-error] hash \'"<<name<<"\' does not have a member named \'"<<_name<<"\'"<<std::endl;
 	return error_var;
 }
+abstract_syntax_tree& var::get_function()
+{
+	return function;
+}
 #endif
diff --git a/balloon/main.cpp b/balloon/main.cpp
index 6ce9a40..037d1f5 100644
--- a/balloon/main.cpp
+++ b/balloon/main.cpp
@@ -83,6 +83,12 @@ int main()
 			{
 				pas.get_detail_token_stream(lex.get_detail_token());
 				pas.parse_main();
+				if(!pas.get_error())
+				{
+					pas.run_tree();
+				}
+				else
+					std::cout<<">>[Parse] error(s) found,stop."<<std::endl;
 			}
 			else
 				std::cout<<">>[Lexer] error(s) found,stop."<<std::endl;