diff --git a/version2.0/main.cpp b/version2.0/main.cpp
index 743284a..740647e 100644
--- a/version2.0/main.cpp
+++ b/version2.0/main.cpp
@@ -25,6 +25,7 @@ int main()
 			std::cout<<">> [lexer ] turn code into tokens."<<std::endl;
 			std::cout<<">> [parser] turn tokens into abstract syntax tree."<<std::endl;
 			std::cout<<">> [ast   ] check the abstract syntax tree."<<std::endl;
+			std::cout<<">> [run   ] run code."<<std::endl;
 			std::cout<<">> [exit  ] quit nasal interpreter."<<std::endl;
 		}
 		else if(command=="cls")
diff --git a/version2.0/nasal_parse.h b/version2.0/nasal_parse.h
index 6d30343..c71f4a2 100644
--- a/version2.0/nasal_parse.h
+++ b/version2.0/nasal_parse.h
@@ -25,6 +25,8 @@ class nasal_parse
 		abstract_syntax_tree string_expr();
 		abstract_syntax_tree nil_expr();
 		abstract_syntax_tree var_outside_definition();
+		abstract_syntax_tree loop_expr();
+		abstract_syntax_tree choose_expr();
 };
 
 void nasal_parse::print_detail_token()
@@ -99,7 +101,7 @@ void nasal_parse::push_token()
 	if(!checked_tokens.empty())
 	{
 		parse_token_stream.push(checked_tokens.top());
-		this_token=checked_token.top();
+		this_token=checked_tokens.top();
 		checked_tokens.pop();
 	}
 	else
@@ -145,7 +147,7 @@ void nasal_parse::main_generate()
 			case __while:
 			case __for:
 			case __foreach:
-			case __forindex:break;
+			case __forindex:this->push_token();root.get_children().push_back(loop_expr());break;
 			case __semi:break;
 			default:++error;print_parse_error(error_token_in_main,this_token.line,this_token.type);
 		}
@@ -186,6 +188,7 @@ abstract_syntax_tree nasal_parse::nil_expr()
 abstract_syntax_tree nasal_parse::var_outside_definition()
 {
 	abstract_syntax_tree definition_node;
+	definition_node.set_type(__definition);
 	this->get_token();
 	if(this_token.type!=__var)
 	{
@@ -204,7 +207,28 @@ abstract_syntax_tree nasal_parse::var_outside_definition()
 		++error;
 		print_parse_error(definition_lack_id,this_token.line);
 	}
-
 	return definition_node;
 }
+
+abstract_syntax_tree nasal_parse::loop_expr()
+{
+	abstract_syntax_tree loop_main_node;
+	loop_main_node.set_type(__loop);
+	this->get_token();
+	switch(this_token.type)
+	{
+		case __for:
+		case __while:
+		case __foreach:
+		case __forindex:break;
+	}
+	return loop_main_node;
+}
+
+abstract_syntax_tree nasal_parse::choose_expr()
+{
+	abstract_syntax_tree choose_main_node;
+	choose_main_node.set_type(__ifelse);
+	return choose_main_node;
+}
 #endif
diff --git a/version2.0/parse.bnf b/version2.0/parse.bnf
index 9d0d9e1..35aa624 100644
--- a/version2.0/parse.bnf
+++ b/version2.0/parse.bnf
@@ -6,28 +6,61 @@
 
 <number> ::= <token_number>
 <string> ::= <token_string>
+<nil> ::= <token_reserve_word_nil>
 <id> ::= <token_identifier>
 <dynamic_id> ::= <token_dynamic_id>
+
+<vector> ::= <[> {<scalar> <,>} <]>
+<hash> ::= <{> {(<id> | <string>) <:> <scalar> <,>} <}>
 <scalar> ::=
+    <number>
+|   <nil>
+|   <string>
+|   <call_identifier>
+|   <calculation>
+|   <function>
+|   <(> <scalar> <)>
+|   <hash>
+|   <vector>
 
-<calculation_expr> ::=
-    <or_expr> {<and> <or_expr>}
-<or_expr> ::=
-    <unary_expr> {<or> <unary_expr>}
-|   <unary_expr> {<or> <additive_expr>}
-|   <additive_expr> {<or> <unary_expr>}
-|   <additive_expr> {<or> <additive_expr>}
-<unary_expr> ::=
-    <-> <additive_expr>
-|   <!> <additive_expr>
-<additive_expr> ::=
-    <multive_expr> {<+> <multive_expr>}
-|   <multive_expr> {<-> <multive_expr>}
-|   <multive_expr> {<~> <multive_expr>} 
-<multive_expr> ::=
-    <scalar> {<*> <scalar>}
-|   <scalar> {</> <scalar>}
+<function> ::=
+    <func> [<(> <)>] <statement>
+|   <func> [<(> <)>] <{> {<statement> <;>} <}>
+|   <func> <(> {<id> <,>} {<id> <=> <scalar> <,>} {<dynamic_id>} <)> <statement>
+|   <func> <(> {<id> <,>} {<id> <=> <scalar> <,>} {<dynamic_id>} <)> <{> {<statement> <;>} <}>
 
+<call_identifier> ::=
+    <scalar> { (<[> {<scalar> <,>} <]>) | (<[> <scalar> <:> [<scalar>] <]>) | (<.> <id>) | (<(> {<scalar> <,>} <)>) | (<(> {<id> <:> <scalar> <,>} <)>) }
+|   <id> { (<[> {<scalar> <,>} <]>) | (<[> <scalar> <:> [<scalar>] <]>) | (<.> <id>) | (<(> {<scalar> <,>} <)>) | (<(> {<id> <:> <scalar> <,>} <)>) }
+|   <func> <id>
+|   <func> <id> <(>  <)> { (<[> {<scalar> <,>} <]>) | (<[> <scalar> <:> [<scalar>] <]>) | (<.> <id>) | (<(> {<scalar> <,>} <)>) | (<(> {<id> <:> <scalar> <,>} <)>) }
+
+<calculation> ::=
+    <and_calc>
+|   <or_calc>
+|   <additive_calc>
+|   <multive_calc>
+|   <scalar>
+<and_calc> ::=
+    <or_calc> {<and> <or_calc>}
+<or_calc> ::=
+    <additive_calc> {<or> <additive_calc>}
+<additive_calc> ::=
+    <multive_calc> {<+>|<->|<~> <multive_calc>}
+<multive_calc> ::=
+    <scalar> {<*>|</> <scalar>}
+
+<definition> ::=
+    <var> <id>
+|   <var> <id> <=> <scalar>
+|   <var> <(> {(<id>) | (<call_identifier>) <,>} <)> <=> <scalar>
+|   <(> <var> {(<id>) | (<call_identifier>) <,>} <)> <=> <scalar>
+|   <var> <(> {(<id>) | (<call_identifier>) <,>} <)> <=> <(> {<scalar> <,>} <)>
+|   <(> <var> {(<id>) | (<call_identifier>) <,>} <)> <=> <(> {<scalar> <,>} <)>
+<assignment> ::=
+    <call_identifier> <=> <scalar>
+|   <(> {<call_identifier> <,>} <)> <=> <scalar>
+|   <(> {<call_identifier> <,>} <)> <=> <(> {<scalar> <,>} <)>
 <loop_expr> ::=
     <for_loop>
 |   <while_loop>
@@ -38,13 +71,13 @@
 |   <for> <(> [<statement>] <;> [<scalar>] <;> <statement> <)> <{> {<statement> <;>} <}>
 <while_loop> ::=
     <while> <(> <scalar> <)> <statement> [<;>]
-|   <while> <(> <scalar> <) <{> {<statement> <;>} <}>
+|   <while> <(> <scalar> <)> <{> {<statement> <;>} <}>
 <forindex_loop> ::=
     <forindex> <(> [<statement] <;> [<scalar>] <)> <statement> [<;>]
-|   <forindex> <(> [<statement] <;> [<scalar>] <) <{> {<statement> <;>} <}>
+|   <forindex> <(> [<statement] <;> [<scalar>] <)> <{> {<statement> <;>} <}>
 <foreach_loop> ::=
     <foreach> <(> [<statement] <;> [<scalar>] <)> <statement> [<;>]
-|   <foreach> <(> [<statement] <;> [<scalar>] <) <{> {<statement> <;>} <}>
+|   <foreach> <(> [<statement] <;> [<scalar>] <)> <{> {<statement> <;>} <}>
 
 <choose_expr> ::= <choose_expr_if> {<choose_expr_elsif>} [<choose_expr_else>]
 <choose_expr_if> ::=
@@ -57,7 +90,7 @@
 |   <else> <if> <(> <scalar> <)> <{> {<statement> <;>} <}>
 <choose_expr_else> ::=
     <else> <statement> [<;>]
-|   <else> {<statement> <;>} <}>
+|   <else> <{> {<statement> <;>} <}>
 
 <continue_expr> ::= <continue>
 <break_expr> ::= <break>