diff --git a/balloon/abstract_syntax_tree.cpp b/balloon/abstract_syntax_tree.cpp
index b81111d..6063bb7 100644
--- a/balloon/abstract_syntax_tree.cpp
+++ b/balloon/abstract_syntax_tree.cpp
@@ -2,6 +2,13 @@
 #define __ABSTRACT_SYNTAX_TREE_CPP__
 
 int exit_type=0;
+
+bool abstract_syntax_tree::check()
+{
+	
+	return true;
+}
+
 var abstract_syntax_tree::call_id()
 {
 	var temp;
@@ -71,6 +78,9 @@ void abstract_syntax_tree::run_root()
 			std::string _name=j->name;
 			if(!scope.search_var(_name))
 			{
+				++j;
+				if(j!=i->children.end())
+					new_var=j->get_value();
 				new_var.set_name(_name);
 				scope.add_new_var(new_var);
 			}
@@ -89,11 +99,15 @@ void abstract_syntax_tree::run_root()
 			std::cout<<i->call_id().get_name()<<std::endl;
 		else if(i->type==__while)
 		{
-			;
+			scope.add_new_block_scope();
+			i->run_loop();
+			scope.pop_last_block_scope();
 		}
 		else if(i->type==__ifelse)
 		{
-			;
+			scope.add_new_block_scope();
+			i->run_ifelse();
+			scope.pop_last_block_scope();
 		}
 		if(exit_type!=__process_exited_successfully)
 			break;
@@ -107,6 +121,26 @@ void abstract_syntax_tree::run_root()
 	return;
 }
 
+void abstract_syntax_tree::run_loop()
+{
+	scope.add_new_local_scope();
+	
+	abstract_syntax_tree condition=children.front();
+	abstract_syntax_tree blk=children.back();
+	while(condition.check())
+		blk.run_block(__loop);
+	scope.pop_last_local_scope();
+	return;
+}
+
+void abstract_syntax_tree::run_ifelse()
+{
+	scope.add_new_local_scope();
+	
+	scope.pop_last_local_scope();
+	return;
+}
+
 void abstract_syntax_tree::run_func()
 {
 	scope.add_new_block_scope();
@@ -119,13 +153,10 @@ void abstract_syntax_tree::run_func()
 void abstract_syntax_tree::run_block(int block_type)
 {
 	scope.add_new_local_scope();
-	
+
 	scope.pop_last_local_scope();
 	return;
 }
 
-		
-
-		
 
 #endif
diff --git a/balloon/abstract_syntax_tree.h b/balloon/abstract_syntax_tree.h
index 3b67440..dd8733a 100644
--- a/balloon/abstract_syntax_tree.h
+++ b/balloon/abstract_syntax_tree.h
@@ -191,9 +191,12 @@ class abstract_syntax_tree
 		{
 			return children;
 		}
+		bool check();
 		var call_id();
 		var get_value();
 		void run_root();
+		void run_loop();
+		void run_ifelse();
 		void run_func();
 		void run_block(int);
 };
diff --git a/balloon/balloon_parse.h b/balloon/balloon_parse.h
index 86e5422..6a1a534 100644
--- a/balloon/balloon_parse.h
+++ b/balloon/balloon_parse.h
@@ -275,8 +275,9 @@ abstract_syntax_tree balloon_parse::definition()
 	get_token();
 	if(this_token.type!=__equal)
 	{
-		++error;
-		std::cout<<">>[Parse-error] line "<<this_token.line<<": expect a \'=\' here."<<std::endl;
+		++warning;
+		std::cout<<">>[Parse-warning] line "<<this_token.line<<": every new var should be initialized."<<std::endl;
+		parse.push(this_token);
 		return new_node;
 	}
 	new_node.add_child(scalar());
diff --git a/balloon/balloon_scope.h b/balloon/balloon_scope.h
index 1a320a4..40b5659 100644
--- a/balloon/balloon_scope.h
+++ b/balloon/balloon_scope.h
@@ -4,34 +4,108 @@
 class balloon_scope
 {
 	private:
-		std::list<var> scope;
-		var error_var;
+		std::list<var> global;
+		std::list<std::list<std::list<var> > > scope_list;
 	public:
 		void set_clear()
 		{
-			scope.clear();
+			global.clear();
+			scope_list.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;
+			if(!scope_list.empty())
+			{
+				std::list<std::list<var> >::iterator i=scope_list.back().end();
+				--i;
+				for(;;--i)
+				{
+					for(std::list<var>::iterator j=i->begin();j!=i->end();++j)
+						if(j->get_name()==name)
+							return true;
+					if(i==scope_list.back().begin())
+						break;
+				}
+			}
+			if(!global.empty())
+			{
+				for(std::list<var>::iterator i=global.begin();i!=global.end();++i)
+					if(i->get_name()==name)
+						return true;
+			}
 			return false;
 		}
-		void add_var(var t)
+		void add_new_var(var t)
 		{
-			scope.push_back(t);
+			if(!scope_list.empty())
+			{
+				std::list<std::list<var> >::iterator i=scope_list.back().end();
+				--i;
+				i->push_back(t);
+				return;
+			}
+			global.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;
+			if(!scope_list.empty())
+			{
+				std::list<std::list<var> >::iterator i=scope_list.back().end();
+				--i;
+				// get the last scope block(std::list<std::list<var> >)
+				for(;;--i)
+				{
+					for(std::list<var>::iterator j=i->begin();j!=i->end();++j)
+						if(j->get_name()==name)
+							return *j;
+					if(i==scope_list.back().begin())
+						break;
+				}
+			}
+			if(!global.empty())
+			{
+				for(std::list<var>::iterator i=global.begin();i!=global.end();++i)
+					if(i->get_name()==name)
+						return *i;
+			}
 			return error_var;
 		}
+		void add_new_block_scope()
+		{
+			std::list<std::list<var> > new_list;
+			scope_list.push_back(new_list);
+			return;
+		}
+		void add_new_local_scope()
+		{
+			if(!scope_list.empty())
+			{
+				std::list<std::list<std::list<var> > >::iterator i=scope_list.end();
+				--i;
+				std::list<var> new_list;
+				i->push_back(new_list);
+			}
+			return;
+		}
+		void pop_last_block_scope()
+		{
+			if(!scope_list.empty())
+				scope_list.pop_back();
+			return;
+		}
+		void pop_last_local_scope()
+		{
+			if(!scope_list.empty())
+			{
+				std::list<std::list<var> > temp=scope_list.back();
+				temp.pop_back();
+			}
+			return;
+		}
 };
 
+balloon_scope scope;
+
 #endif
diff --git a/balloon/loop.txt b/balloon/loop.txt
new file mode 100644
index 0000000..45758d6
--- /dev/null
+++ b/balloon/loop.txt
@@ -0,0 +1,8 @@
+var a=1;
+var sum=0;
+while(a!=100)
+{
+    sum+=a;
+    a+=1;
+}
+print(sum);
\ No newline at end of file
diff --git a/balloon/main.cpp b/balloon/main.cpp
index a39a081..b7f8314 100644
--- a/balloon/main.cpp
+++ b/balloon/main.cpp
@@ -86,9 +86,7 @@ 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;
 			}
diff --git a/balloon/var.txt b/balloon/var.txt
new file mode 100644
index 0000000..b45120a
--- /dev/null
+++ b/balloon/var.txt
@@ -0,0 +1,19 @@
+var a=1;
+var b=2;
+var c="string";
+var d;
+var e=[];
+var f={};
+var g=[0,'str',[],{}];
+var h={
+    va1:1,
+    va2:"str",
+    va3:'s',
+    va4:[],
+    va5:{fuck:0}
+};
+a=2;
+var i=func(v1,v2,v3){return [0,0,0];};
+1073741824;
+"str";
+a;
\ No newline at end of file