diff --git a/Cargo.lock b/Cargo.lock
index a606925..fcb412e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4,4 +4,4 @@ version = 3
 
 [[package]]
 name = "key-lang"
-version = "0.1.3"
+version = "0.1.4"
diff --git a/Cargo.toml b/Cargo.toml
index 6c5e346..4584a70 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "key-lang"
-version = "0.1.3"
+version = "0.1.4"
 edition = "2021"
 description = "To be the prettiest and simpliest script"
 license = "MPL-2.0"
diff --git a/samples/helloworld.ks b/samples/helloworld.ks
index 967c990..358a0c2 100644
--- a/samples/helloworld.ks
+++ b/samples/helloworld.ks
@@ -1,9 +1,10 @@
 mod D:\code\rs\tst\target\debug\tstlib.dll> m;
 
-let s = "芙
-卡
-洛
-斯";
-for c: s.lines() {
-  log(c)
+let iter;
+{
+  let a = "启动启动启动!";
+  iter = a.lines();
+}
+for l:iter {
+  log(l);
 }
diff --git a/src/main.rs b/src/main.rs
index 96d8804..91335aa 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -28,7 +28,7 @@ static mut LINE:usize = 1;
 static mut PLACE:String = String::new();
 
 /// 标志解释器的版本
-static VERSION:usize = 100003;
+static VERSION:usize = 100004;
 
 /// 解释器发行者(用于区分主版本和魔改版)
 /// 
diff --git a/src/native.rs b/src/native.rs
index 9af9e25..7c36ce4 100644
--- a/src/native.rs
+++ b/src/native.rs
@@ -52,7 +52,8 @@ struct FuncTable {
   get_self: fn(Scope)-> *mut Litr,
   get_parent: fn(Scope)-> Option<Scope>,
   outlive_inc: fn(Scope),
-  outlive_dec: fn(Scope)
+  outlive_dec: fn(Scope),
+  symcls: fn()-> *mut NativeClassDef
 }
 static FUNCTABLE:FuncTable = FuncTable {
   intern, 
@@ -72,6 +73,7 @@ static FUNCTABLE:FuncTable = FuncTable {
   get_parent: |cx|cx.parent,
   outlive_inc: outlive::increase_scope_count,
   outlive_dec: outlive::decrease_scope_count,
+  symcls: ||unsafe{crate::primitive::sym::SYMBOL_CLASS}
 };
 
 /// 原生类型实例
diff --git a/src/primitive/sym.rs b/src/primitive/sym.rs
index dc13a3b..e2cc81a 100644
--- a/src/primitive/sym.rs
+++ b/src/primitive/sym.rs
@@ -4,7 +4,7 @@ use crate::{
 
 pub const ITER_END:usize = 1;
 
-static mut SYMBOL_CLASS: *mut NativeClassDef = std::ptr::null_mut();
+pub static mut SYMBOL_CLASS: *mut NativeClassDef = std::ptr::null_mut();
 
 pub fn init()-> (Interned, *mut NativeClassDef) {
   unsafe {
@@ -14,6 +14,7 @@ pub fn init()-> (Interned, *mut NativeClassDef) {
       ]
     );
     SYMBOL_CLASS = s.1;
+    (*SYMBOL_CLASS).to_str = to_str;
     s
   }
 }