From c1b5bee86c302b0cd284d3dd6220636695d62ba3 Mon Sep 17 00:00:00 2001
From: zswang <wjhu111@21cn.com>
Date: Thu, 5 Nov 2015 18:07:11 +0800
Subject: [PATCH] add schema "virtual".

---
 bower.json                 |   2 +-
 example.jdists.js          |  35 +++---
 jpacks.dev.js              | 186 +++++++++++++++++++++-------
 jpacks.js                  | 181 +++++++++++++++++++++------
 jpacks.min.js              |   2 +-
 package.json               |   4 +-
 schemas-extend/bigint.js   |  10 +-
 schemas-extend/protobuf.js |   8 +-
 schemas-extend/zlib.js     |  10 +-
 src/jpacks.js              |   2 +
 src/schema.js              |  46 ++++---
 src/schemas/array.js       |  11 +-
 src/schemas/bytes.js       |   2 +-
 src/schemas/cases.js       |   2 +-
 src/schemas/cstring.js     |   2 +-
 src/schemas/depend.js      |   4 +-
 src/schemas/enums.js       |   6 +-
 src/schemas/number.js      |   2 +-
 src/schemas/object.js      |   4 +-
 src/schemas/parse.js       |   2 +-
 src/schemas/string.js      |   2 -
 src/schemas/union.js       |   2 +-
 src/schemas/virtual.js     | 117 ++++++++++++++++++
 test/example.js            | 243 +++++++++++++++++++++++--------------
 version.jdists             |   1 +
 25 files changed, 635 insertions(+), 251 deletions(-)
 create mode 100644 src/schemas/virtual.js

diff --git a/bower.json b/bower.json
index 0a8b147..9734ed6 100644
--- a/bower.json
+++ b/bower.json
@@ -1,7 +1,7 @@
 {
   "name": "jpacks",
   "description": "Binary data packing and unpacking.",
-  "version": "0.3.13",
+  "version": "0.3.15",
   "homepage": "https://github.com/zswang/jpacks",
   "authors": {
     "name": "zswang",
diff --git a/example.jdists.js b/example.jdists.js
index 798dbd3..58a760d 100644
--- a/example.jdists.js
+++ b/example.jdists.js
@@ -39,23 +39,18 @@ forEach(function (item) {
 });
 /*</jdists>*/
 
-<!--jdists export="#pattern">/^\s*\*\s*@example\s*(.*)$/mg</jdists-->
-<!--jdists export="#replacement">  it("$1", function () {</jdists-->
-<!--jdists encoding="regex" import="#example" pattern="#pattern" replacement="#replacement" export="#example" /-->
-
-<!--jdists export="#pattern">/^\s*```js\s*$/mg</jdists-->
-<!--jdists export="#replacement"></jdists-->
-<!--jdists encoding="regex" import="#example" pattern="#pattern" replacement="#replacement" export="#example" /-->
-
-<!--jdists export="#pattern">/^\s*```\s*$/mg</jdists-->
-<!--jdists export="#replacement">  });</jdists-->
-<!--jdists encoding="regex" import="#example" pattern="#pattern" replacement="#replacement" export="#example" /-->
-
-<!--jdists export="#pattern">/console\.log/g</jdists-->
-<!--jdists export="#replacement">print</jdists-->
-<!--jdists encoding="regex" import="#example" pattern="#pattern" replacement="#replacement" export="#example" /-->
-
-<!--jdists export="#pattern">/\/\/ -?>\s*(.*)/gm</jdists-->
-<!--jdists export="#replacement">assert.equal(printValue, '$1'); printValue = undefined;</jdists-->
-<!--jdists encoding="regex" import="#example" pattern="#pattern" replacement="#replacement" export="#example" /-->
-/*<jdists import="#example"/>*/
+/*<jdists export="#replacer">*/
+function (content) {
+  content = content.replace(/^\s*\*\s*@example\s*(.*)$/mg,
+    '  it("$1", function () {');
+  content = content.replace(/^\s*```js\s*$/mg, '');
+  content = content.replace(/\/\/ -?>\s*(.*)/gm, function (all, output) {
+    return '    assert.equal(printValue, ' + JSON.stringify(output) + '); printValue = undefined;'
+  });
+  content = content.replace(/console\.log/g, 'print');
+  content = content.replace(/^\s*```\s*$/mg,
+    '  });');
+  return content;
+}
+/*</jdists>*/
+/*<jdists encoding="#replacer" import="#example"/>*/
diff --git a/jpacks.dev.js b/jpacks.dev.js
index 7ce9264..5b87b31 100644
--- a/jpacks.dev.js
+++ b/jpacks.dev.js
@@ -5,7 +5,7 @@
    * Binary data packing and unpacking.
    * @author
    *   zswang (http://weibo.com/zswang)
-   * @version 0.3.13
+   * @version 0.3.15
    * @date 2015-11-05
    */
   function createSchema() {
@@ -38,7 +38,7 @@
    */
   function Schema(options) {
     var self = this;
-    Object.keys(options).forEach(function (key) {
+    Object.keys(options).forEach(function(key) {
       self[key] = options[key];
     });
   }
@@ -49,7 +49,7 @@
    * @param {Schema|string|Function} schema 数据结构或者数据结构名
    * @return {boolean} 返回是否定义成功
    */
-  Schema.register = function (name, schema) {
+  Schema.register = function(name, schema) {
     /*<safe>*/
     if (typeof name === 'undefined') {
       throw new Error('Parameter "name" is undefined.');
@@ -93,7 +93,7 @@
    *   function _pattern(schema) {}
    * ]]]
    */
-  Schema.pushPattern = function (pattern) {
+  Schema.pushPattern = function(pattern) {
     /*<safe>*/
     if (typeof pattern !== 'function') {
       return;
@@ -107,7 +107,7 @@
    * @param {string|Object|Schema} schema 数据结构名
    * @return {Schema} 返回名字对应的数据结构
    */
-  Schema.from = function (schema) {
+  Schema.from = function(schema) {
     /*<safe>*/
     if (typeof schema === 'undefined') { // 无效数据
       return;
@@ -147,7 +147,7 @@
    */
   function setDefaultOptions(options) {
     options = options || {};
-    Object.keys(options).forEach(function (key) {
+    Object.keys(options).forEach(function(key) {
       defaultOptions[key] = options[key];
     });
   }
@@ -187,7 +187,7 @@
     buffer = arrayBufferFrom(buffer); // 确保是 ArrayBuffer 类型
     options = options || {};
     offsets = offsets || [0];
-    Object.keys(defaultOptions).forEach(function (key) {
+    Object.keys(defaultOptions).forEach(function(key) {
       if (typeof options[key] === 'undefined') {
         options[key] = defaultOptions[key];
       }
@@ -213,7 +213,7 @@
     }
     buffer = buffer || [];
     options = options || {};
-    Object.keys(defaultOptions).forEach(function (key) {
+    Object.keys(defaultOptions).forEach(function(key) {
       if (typeof options[key] === 'undefined') {
         options[key] = defaultOptions[key];
       }
@@ -294,39 +294,45 @@
       return result.join();
     }
     function scan(obj) {
+      // if (obj === null) {
+      //   return 'null';
+      // }
       if (!obj) {
         return obj;
       }
       if (obj.namespace) {
         if (obj.namespace === 'number') {
-          return obj.name;
+          return "'" + obj.name + "'";
         }
         if (obj.args) {
           return obj.namespace + '(' + stringify.apply(null, obj.args) + ')';
         }
-        return obj.namespace;
-      }
-      if (obj.name) {
-        return obj.name;
+        return "'" + obj.namespace + "'";
       }
       if (typeof obj === 'function') {
-        obj.name = '_pack_fn' + (guid++);
-        Schema.define(obj.name, obj);
-        return obj.name;
-      }
-      if (typeof obj === 'object') {
+        if (!obj.name) {
+          obj.name = '_pack_fn' + (guid++);
+          Schema.define(obj.name, obj);
+        }
+      } else if (typeof obj === 'object') {
         var result = new obj.constructor();
-        Object.keys(obj).forEach(function (key) {
+        Object.keys(obj).forEach(function(key) {
           result[key] = scan(obj[key]);
         });
         return result;
       }
+      if (obj.name) {
+        return "'" + obj.name + "'";
+      }
+      if (typeof obj === 'string') {
+        return "'" + obj + "'";
+      }
       return obj;
     }
     return JSON.stringify(scan(obj) || '').replace(/"/g, '');
   }
   Schema.stringify = stringify;
-  Schema.prototype.toString = function () {
+  Schema.prototype.toString = function() {
     return stringify(this);
   };
   return Schema;
@@ -359,7 +365,7 @@
     });
     var _schema = _.union(_map, 8);
     console.log(_.stringify(_schema));
-    // > union({bytes:array(uint8,8),int8:int8,int16:int16,int32:int32,uint8:uint8,uint16:uint16,uint32:uint32,float32:float32,float64:float64,shortint:shortint,smallint:smallint,longint:longint,byte:byte,word:word,longword:longword},8)
+    // > union({bytes:array('uint8',8),int8:'int8',int16:'int16',int32:'int32',uint8:'uint8',uint16:'uint16',uint32:'uint32',float32:'float32',float64:'float64',shortint:'shortint',smallint:'smallint',longint:'longint',byte:'byte',word:'word',longword:'longword'},8)
     var buffer = _.pack(_schema, {
       bytes: [0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, 0x89]
     });
@@ -471,7 +477,7 @@
     var _ = jpacks;
     var _schema = jpacks.array('int16', 2);
     console.log(String(_schema));
-    // > array(int16,2)
+    // > array('int16',2)
     var value = [12337, 12851];
     var buffer = jpacks.pack(_schema, value);
     console.log(buffer.join(' '));
@@ -484,7 +490,7 @@
     var _ = jpacks;
     var _schema = jpacks.array('int16', 'int8');
     console.log(String(_schema));
-    // > array(int16,int8)
+    // > array('int16','int8')
     var value = [12337, 12851];
     var buffer = jpacks.pack(_schema, value);
     console.log(buffer.join(' '));
@@ -497,7 +503,7 @@
     var _ = jpacks;
     var _schema = jpacks.array('int16')(6);
     console.log(String(_schema));
-    // > array(int16,6)
+    // > array('int16',6)
     var value = [12337, 12851];
     var buffer = jpacks.pack(_schema, value);
     console.log(buffer.join(' '));
@@ -522,11 +528,6 @@
       size = itemSchema.size * count;
     } else {
       countSchema = Schema.from(count);
-      /*<safe>*/
-      if (countSchema.namespace !== 'number') {
-        throw new Error('Parameter "count" is not a numeric type.');
-      }
-      /*</safe>*/
     }
     return new Schema({
       unpack: function _unpack(buffer, options, offsets) {
@@ -599,7 +600,7 @@
     var _ = jpacks;
     var _schema = jpacks.bytes(6);
     console.log(String(_schema));
-    // > array(uint8,6)
+    // > array('uint8',6)
     var value = [0, 1, 2, 3, 4, 5];
     var buffer = jpacks.pack(_schema, value);
     console.log(buffer.join(' '));
@@ -624,7 +625,7 @@
     var _ = jpacks;
     var _schema = _.object([_.shortString, _.word]);
     console.log(_.stringify(_schema));
-    // > object([string(uint8),uint16])
+    // > object([string('uint8'),'uint16'])
     var buffer = _.pack(_schema, ['zswang', 1978]);
     console.log(buffer.join(' '));
     // > 6 122 115 119 97 110 103 186 7
@@ -639,7 +640,7 @@
       year: _.word
     });
     console.log(_.stringify(_schema));
-    // > object({namespace:string,args:{0:uint8}})
+    // > object({name:string('uint8'),year:'uint16'})
     var buffer = _.pack(_schema, {
         name: 'zswang',
         year: 1978
@@ -715,7 +716,7 @@
       content: _.shortString
     }, 20);
     console.log(_.stringify(_schema));
-    // > union({length:uint8,content:string(uint8)},20)
+    // > union({length:'uint8',content:string('uint8')},20)
     var buffer = _.pack(_schema, {
       content: '0123456789'
     });
@@ -782,7 +783,7 @@
     var _ = jpacks;
     var _schema = _.enums(['Sun', 'Mon', 'Tues', 'Wed', 'Thur', 'Fri', 'Sat'], 'uint8');
     console.log(_.stringify(_schema));
-    // > enums({Sun:0,Mon:1,Tues:2,Wed:3,Thur:4,Fri:5,Sat:6},uint8)
+    // > enums({Sun:0,Mon:1,Tues:2,Wed:3,Thur:4,Fri:5,Sat:6},'uint8')
     var buffer = _.pack(_schema, 'Tues');
     console.log(buffer.join(' '));
     // > 2
@@ -801,7 +802,7 @@
       NotFound: 404
     }, 'int8');
     console.log(_.stringify(_schema));
-    // > enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},int8)
+    // > enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},'int8')
     var buffer = _.pack(_schema, 'Unknown');
     console.log(buffer.join(' '));
     // > 255
@@ -819,7 +820,7 @@
       NotFound: 404
     }, 'int8');
     console.log(_.stringify(_schema));
-    // > enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},int8)
+    // > enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},'int8')
     var buffer = _.pack(_schema, 2);
     console.log(buffer.join(' '));
     // > 2
@@ -966,8 +967,6 @@
     // > 228 189 160 229 165 189 228 184 150 231 149 140 239 188 129 72 101 108 108 111 0 0 0 0 0
     console.log(_.unpack(_schema, buffer));
     // > 你好世界！Hello
-   '''<example>'''
-   '''<example>'''
    * @example stringCreator():dynamic
     var _ = jpacks;
     var _schema = _.string('int8');
@@ -1086,7 +1085,7 @@
     var _ = jpacks;
     var _schema = _.array(_.pchar, 'uint8');
     console.log(_.stringify(_schema));
-    // > array(cstring(true),uint8)
+    // > array(cstring(true),'uint8')
     var buffer = _.pack(_schema, ['abc', 'defghijk', 'g']);
     console.log(buffer.join(' '));
     // > 3 97 98 99 0 100 101 102 103 104 105 106 107 0 103 0
@@ -1150,7 +1149,7 @@
       ]))
     };
     console.log(_.stringify(_schema));
-    // > {type:string(uint8),data:depend(type,cases([[name,string(uint8)],[age,uint8]]))}
+    // > {type:string('uint8'),data:depend('type',cases([['name',string('uint8')],['age','uint8']]))}
     var buffer = _.pack(_schema, {
       type: 'name',
       data: 'tom'
@@ -1207,7 +1206,7 @@
    *    function schemaCreator(value) {}
    * ]]]
    '''<example>'''
-   * @example dependCreator()
+   * @example dependCreator():base
     ```js
     var _ = jpacks;
     var _schema = _.object({
@@ -1217,7 +1216,7 @@
       data2: _.depend('length2', _.array(_.shortString))
     });
     console.log(_.stringify(_schema));
-    // > object({length1:int8,length2:int8,data1:depend(length1,bytes),data2:depend(length2,array(string(uint8)))})
+    // > object({length1:'int8',length2:'int8',data1:depend('length1','bytes'),data2:depend('length2',array(string('uint8')))})
     var buffer = _.pack(_schema, {
       length1: 2,
       length2: 3,
@@ -1290,7 +1289,7 @@
     };
     var _schema = _.parse(_xor, _xor, 'float64', 8);
     console.log(_.stringify(_schema));
-    // > parse(_xor,_xor,float64,8)
+    // > parse('_xor','_xor','float64',8)
     var buffer = _.pack(_schema, 2.94296650666094e+189);
     console.log(buffer.join(' '));
     // > 111 75 41 7 126 92 58 24
@@ -1327,6 +1326,107 @@
     fn.args = args;
   });
   Schema.register('parse', parse);
+  /**
+   * 定义一个虚拟结构
+   *
+   * @param {number|string} operator
+   * @param {object} value 数据结构
+   '''<example>'''
+   * @example virtualCreator:number
+    ```js
+    var _ = jpacks;
+    var _schema = _.object({
+      f1: 'uint16',
+      v1: _.depend('f1', _.virtual(-4))
+    });
+    console.log(_.stringify(_schema))
+    // > object({f1:'uint16',v1:depend('f1',virtual(-4))})
+    var buffer = _.pack(_schema, {
+      f1: 4
+    });
+    console.log(buffer.join(' '));
+    // > 4 0
+    console.log(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+    // > {"f1":1024,"v1":1020}
+    ```
+   * @example virtualCreator:string
+    ```js
+    var _ = jpacks;
+    var _schema = _.object({
+      name: _.shortString,
+      welcome: _.depend('name', _.virtual('Hello '))
+    });
+    console.log(_.stringify(_schema))
+    // > object({name:string('uint8'),welcome:depend('name',virtual('Hello '))})
+    var buffer = _.pack(_schema, {
+      name: 'World!'
+    });
+    console.log(buffer.join(' '));
+    // > 6 87 111 114 108 100 33
+    console.log(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+    // > {"name":"World!","welcome":"Hello World!"}
+    ```
+   * @example virtualCreator:depend
+    ```js
+    var _ = jpacks;
+    var _schema = _.object({
+      name: _.shortString,
+      welcome: _.depend('name', _.cases([
+        ['zswang', _.depend('name', _.virtual('Hello '))],
+        ['wang', _.depend('name', _.virtual('Hi '))]
+      ]))
+    });
+    console.log(_.stringify(_schema))
+    // > object({name:string('uint8'),welcome:depend('name',cases([['zswang',depend('name',virtual('Hello '))],['wang',depend('name',virtual('Hi '))]]))})
+    var buffer = _.pack(_schema, {
+      name: 'zswang'
+    });
+    console.log(buffer.join(' '));
+    // > 6 122 115 119 97 110 103
+    console.log(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+    // > {"name":"zswang","welcome":"Hello zswang"}
+    var buffer = _.pack(_schema, {
+      name: 'wang'
+    });
+    console.log(buffer.join(' '));
+    // > 4 119 97 110 103
+    console.log(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+    // > {"name":"wang","welcome":"Hi wang"}
+   ```
+   '''</example>'''
+   */
+  function virtualCreator(operator, value) {
+    return new Schema({
+      unpack: function _unpack() {
+        if (/string|number/.test(typeof operator)) {
+          return operator + value;
+        }
+        if (typeof operator === 'function') {
+          return operator(value);
+        }
+        return value;
+      },
+      pack: function _pack() {},
+      args: arguments,
+      namespace: 'virtual'
+    });
+  }
+  var virtual = Schema.together(virtualCreator, function (fn, args) {
+    fn.namespace = 'virtual';
+    fn.args = args;
+  });
+  Schema.register('virtual', virtual);
+  Schema.pushPattern(function _virtualPattern(schema) {
+    if (typeof schema === 'virtual') {
+      if (schema instanceof Schema) {
+        return;
+      }
+      if (schema instanceof Array) {
+        return;
+      }
+      return virtual(schema);
+    }
+  });
     return Schema;
   }
   var root = create();
diff --git a/jpacks.js b/jpacks.js
index 20f6d30..e8d12bb 100644
--- a/jpacks.js
+++ b/jpacks.js
@@ -5,7 +5,7 @@
    * Binary data packing and unpacking.
    * @author
    *   zswang (http://weibo.com/zswang)
-   * @version 0.3.13
+   * @version 0.3.15
    * @date 2015-11-05
    */
   function createSchema() {
@@ -38,7 +38,7 @@
    */
   function Schema(options) {
     var self = this;
-    Object.keys(options).forEach(function (key) {
+    Object.keys(options).forEach(function(key) {
       self[key] = options[key];
     });
   }
@@ -49,7 +49,7 @@
    * @param {Schema|string|Function} schema 数据结构或者数据结构名
    * @return {boolean} 返回是否定义成功
    */
-  Schema.register = function (name, schema) {
+  Schema.register = function(name, schema) {
     schemas[name] = schema;
     if (!Schema[name]) { // 避免覆盖系统方法
       Schema[name] = schema;
@@ -88,7 +88,7 @@
    *   function _pattern(schema) {}
    * ]]]
    */
-  Schema.pushPattern = function (pattern) {
+  Schema.pushPattern = function(pattern) {
     schemaPatterns.push(pattern);
   };
   /**
@@ -97,7 +97,7 @@
    * @param {string|Object|Schema} schema 数据结构名
    * @return {Schema} 返回名字对应的数据结构
    */
-  Schema.from = function (schema) {
+  Schema.from = function(schema) {
     if (schema instanceof Schema) {
       return schema;
     }
@@ -132,7 +132,7 @@
    */
   function setDefaultOptions(options) {
     options = options || {};
-    Object.keys(options).forEach(function (key) {
+    Object.keys(options).forEach(function(key) {
       defaultOptions[key] = options[key];
     });
   }
@@ -169,7 +169,7 @@
     buffer = arrayBufferFrom(buffer); // 确保是 ArrayBuffer 类型
     options = options || {};
     offsets = offsets || [0];
-    Object.keys(defaultOptions).forEach(function (key) {
+    Object.keys(defaultOptions).forEach(function(key) {
       if (typeof options[key] === 'undefined') {
         options[key] = defaultOptions[key];
       }
@@ -192,7 +192,7 @@
     }
     buffer = buffer || [];
     options = options || {};
-    Object.keys(defaultOptions).forEach(function (key) {
+    Object.keys(defaultOptions).forEach(function(key) {
       if (typeof options[key] === 'undefined') {
         options[key] = defaultOptions[key];
       }
@@ -273,39 +273,45 @@
       return result.join();
     }
     function scan(obj) {
+      // if (obj === null) {
+      //   return 'null';
+      // }
       if (!obj) {
         return obj;
       }
       if (obj.namespace) {
         if (obj.namespace === 'number') {
-          return obj.name;
+          return "'" + obj.name + "'";
         }
         if (obj.args) {
           return obj.namespace + '(' + stringify.apply(null, obj.args) + ')';
         }
-        return obj.namespace;
-      }
-      if (obj.name) {
-        return obj.name;
+        return "'" + obj.namespace + "'";
       }
       if (typeof obj === 'function') {
-        obj.name = '_pack_fn' + (guid++);
-        Schema.define(obj.name, obj);
-        return obj.name;
-      }
-      if (typeof obj === 'object') {
+        if (!obj.name) {
+          obj.name = '_pack_fn' + (guid++);
+          Schema.define(obj.name, obj);
+        }
+      } else if (typeof obj === 'object') {
         var result = new obj.constructor();
-        Object.keys(obj).forEach(function (key) {
+        Object.keys(obj).forEach(function(key) {
           result[key] = scan(obj[key]);
         });
         return result;
       }
+      if (obj.name) {
+        return "'" + obj.name + "'";
+      }
+      if (typeof obj === 'string') {
+        return "'" + obj + "'";
+      }
       return obj;
     }
     return JSON.stringify(scan(obj) || '').replace(/"/g, '');
   }
   Schema.stringify = stringify;
-  Schema.prototype.toString = function () {
+  Schema.prototype.toString = function() {
     return stringify(this);
   };
   return Schema;
@@ -338,7 +344,7 @@
     });
     var _schema = _.union(_map, 8);
     console.log(_.stringify(_schema));
-    // > union({bytes:array(uint8,8),int8:int8,int16:int16,int32:int32,uint8:uint8,uint16:uint16,uint32:uint32,float32:float32,float64:float64,shortint:shortint,smallint:smallint,longint:longint,byte:byte,word:word,longword:longword},8)
+    // > union({bytes:array('uint8',8),int8:'int8',int16:'int16',int32:'int32',uint8:'uint8',uint16:'uint16',uint32:'uint32',float32:'float32',float64:'float64',shortint:'shortint',smallint:'smallint',longint:'longint',byte:'byte',word:'word',longword:'longword'},8)
     var buffer = _.pack(_schema, {
       bytes: [0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, 0x89]
     });
@@ -450,7 +456,7 @@
     var _ = jpacks;
     var _schema = jpacks.array('int16', 2);
     console.log(String(_schema));
-    // > array(int16,2)
+    // > array('int16',2)
     var value = [12337, 12851];
     var buffer = jpacks.pack(_schema, value);
     console.log(buffer.join(' '));
@@ -463,7 +469,7 @@
     var _ = jpacks;
     var _schema = jpacks.array('int16', 'int8');
     console.log(String(_schema));
-    // > array(int16,int8)
+    // > array('int16','int8')
     var value = [12337, 12851];
     var buffer = jpacks.pack(_schema, value);
     console.log(buffer.join(' '));
@@ -476,7 +482,7 @@
     var _ = jpacks;
     var _schema = jpacks.array('int16')(6);
     console.log(String(_schema));
-    // > array(int16,6)
+    // > array('int16',6)
     var value = [12337, 12851];
     var buffer = jpacks.pack(_schema, value);
     console.log(buffer.join(' '));
@@ -565,7 +571,7 @@
     var _ = jpacks;
     var _schema = jpacks.bytes(6);
     console.log(String(_schema));
-    // > array(uint8,6)
+    // > array('uint8',6)
     var value = [0, 1, 2, 3, 4, 5];
     var buffer = jpacks.pack(_schema, value);
     console.log(buffer.join(' '));
@@ -590,7 +596,7 @@
     var _ = jpacks;
     var _schema = _.object([_.shortString, _.word]);
     console.log(_.stringify(_schema));
-    // > object([string(uint8),uint16])
+    // > object([string('uint8'),'uint16'])
     var buffer = _.pack(_schema, ['zswang', 1978]);
     console.log(buffer.join(' '));
     // > 6 122 115 119 97 110 103 186 7
@@ -605,7 +611,7 @@
       year: _.word
     });
     console.log(_.stringify(_schema));
-    // > object({namespace:string,args:{0:uint8}})
+    // > object({name:string('uint8'),year:'uint16'})
     var buffer = _.pack(_schema, {
         name: 'zswang',
         year: 1978
@@ -676,7 +682,7 @@
       content: _.shortString
     }, 20);
     console.log(_.stringify(_schema));
-    // > union({length:uint8,content:string(uint8)},20)
+    // > union({length:'uint8',content:string('uint8')},20)
     var buffer = _.pack(_schema, {
       content: '0123456789'
     });
@@ -735,7 +741,7 @@
     var _ = jpacks;
     var _schema = _.enums(['Sun', 'Mon', 'Tues', 'Wed', 'Thur', 'Fri', 'Sat'], 'uint8');
     console.log(_.stringify(_schema));
-    // > enums({Sun:0,Mon:1,Tues:2,Wed:3,Thur:4,Fri:5,Sat:6},uint8)
+    // > enums({Sun:0,Mon:1,Tues:2,Wed:3,Thur:4,Fri:5,Sat:6},'uint8')
     var buffer = _.pack(_schema, 'Tues');
     console.log(buffer.join(' '));
     // > 2
@@ -754,7 +760,7 @@
       NotFound: 404
     }, 'int8');
     console.log(_.stringify(_schema));
-    // > enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},int8)
+    // > enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},'int8')
     var buffer = _.pack(_schema, 'Unknown');
     console.log(buffer.join(' '));
     // > 255
@@ -772,7 +778,7 @@
       NotFound: 404
     }, 'int8');
     console.log(_.stringify(_schema));
-    // > enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},int8)
+    // > enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},'int8')
     var buffer = _.pack(_schema, 2);
     console.log(buffer.join(' '));
     // > 2
@@ -908,8 +914,6 @@
     // > 228 189 160 229 165 189 228 184 150 231 149 140 239 188 129 72 101 108 108 111 0 0 0 0 0
     console.log(_.unpack(_schema, buffer));
     // > 你好世界！Hello
-   '''<example>'''
-   '''<example>'''
    * @example stringCreator():dynamic
     var _ = jpacks;
     var _schema = _.string('int8');
@@ -1028,7 +1032,7 @@
     var _ = jpacks;
     var _schema = _.array(_.pchar, 'uint8');
     console.log(_.stringify(_schema));
-    // > array(cstring(true),uint8)
+    // > array(cstring(true),'uint8')
     var buffer = _.pack(_schema, ['abc', 'defghijk', 'g']);
     console.log(buffer.join(' '));
     // > 3 97 98 99 0 100 101 102 103 104 105 106 107 0 103 0
@@ -1092,7 +1096,7 @@
       ]))
     };
     console.log(_.stringify(_schema));
-    // > {type:string(uint8),data:depend(type,cases([[name,string(uint8)],[age,uint8]]))}
+    // > {type:string('uint8'),data:depend('type',cases([['name',string('uint8')],['age','uint8']]))}
     var buffer = _.pack(_schema, {
       type: 'name',
       data: 'tom'
@@ -1135,7 +1139,7 @@
    *    function schemaCreator(value) {}
    * ]]]
    '''<example>'''
-   * @example dependCreator()
+   * @example dependCreator():base
     ```js
     var _ = jpacks;
     var _schema = _.object({
@@ -1145,7 +1149,7 @@
       data2: _.depend('length2', _.array(_.shortString))
     });
     console.log(_.stringify(_schema));
-    // > object({length1:int8,length2:int8,data1:depend(length1,bytes),data2:depend(length2,array(string(uint8)))})
+    // > object({length1:'int8',length2:'int8',data1:depend('length1','bytes'),data2:depend('length2',array(string('uint8')))})
     var buffer = _.pack(_schema, {
       length1: 2,
       length2: 3,
@@ -1210,7 +1214,7 @@
     };
     var _schema = _.parse(_xor, _xor, 'float64', 8);
     console.log(_.stringify(_schema));
-    // > parse(_xor,_xor,float64,8)
+    // > parse('_xor','_xor','float64',8)
     var buffer = _.pack(_schema, 2.94296650666094e+189);
     console.log(buffer.join(' '));
     // > 111 75 41 7 126 92 58 24
@@ -1239,6 +1243,107 @@
     fn.args = args;
   });
   Schema.register('parse', parse);
+  /**
+   * 定义一个虚拟结构
+   *
+   * @param {number|string} operator
+   * @param {object} value 数据结构
+   '''<example>'''
+   * @example virtualCreator:number
+    ```js
+    var _ = jpacks;
+    var _schema = _.object({
+      f1: 'uint16',
+      v1: _.depend('f1', _.virtual(-4))
+    });
+    console.log(_.stringify(_schema))
+    // > object({f1:'uint16',v1:depend('f1',virtual(-4))})
+    var buffer = _.pack(_schema, {
+      f1: 4
+    });
+    console.log(buffer.join(' '));
+    // > 4 0
+    console.log(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+    // > {"f1":1024,"v1":1020}
+    ```
+   * @example virtualCreator:string
+    ```js
+    var _ = jpacks;
+    var _schema = _.object({
+      name: _.shortString,
+      welcome: _.depend('name', _.virtual('Hello '))
+    });
+    console.log(_.stringify(_schema))
+    // > object({name:string('uint8'),welcome:depend('name',virtual('Hello '))})
+    var buffer = _.pack(_schema, {
+      name: 'World!'
+    });
+    console.log(buffer.join(' '));
+    // > 6 87 111 114 108 100 33
+    console.log(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+    // > {"name":"World!","welcome":"Hello World!"}
+    ```
+   * @example virtualCreator:depend
+    ```js
+    var _ = jpacks;
+    var _schema = _.object({
+      name: _.shortString,
+      welcome: _.depend('name', _.cases([
+        ['zswang', _.depend('name', _.virtual('Hello '))],
+        ['wang', _.depend('name', _.virtual('Hi '))]
+      ]))
+    });
+    console.log(_.stringify(_schema))
+    // > object({name:string('uint8'),welcome:depend('name',cases([['zswang',depend('name',virtual('Hello '))],['wang',depend('name',virtual('Hi '))]]))})
+    var buffer = _.pack(_schema, {
+      name: 'zswang'
+    });
+    console.log(buffer.join(' '));
+    // > 6 122 115 119 97 110 103
+    console.log(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+    // > {"name":"zswang","welcome":"Hello zswang"}
+    var buffer = _.pack(_schema, {
+      name: 'wang'
+    });
+    console.log(buffer.join(' '));
+    // > 4 119 97 110 103
+    console.log(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+    // > {"name":"wang","welcome":"Hi wang"}
+   ```
+   '''</example>'''
+   */
+  function virtualCreator(operator, value) {
+    return new Schema({
+      unpack: function _unpack() {
+        if (/string|number/.test(typeof operator)) {
+          return operator + value;
+        }
+        if (typeof operator === 'function') {
+          return operator(value);
+        }
+        return value;
+      },
+      pack: function _pack() {},
+      args: arguments,
+      namespace: 'virtual'
+    });
+  }
+  var virtual = Schema.together(virtualCreator, function (fn, args) {
+    fn.namespace = 'virtual';
+    fn.args = args;
+  });
+  Schema.register('virtual', virtual);
+  Schema.pushPattern(function _virtualPattern(schema) {
+    if (typeof schema === 'virtual') {
+      if (schema instanceof Schema) {
+        return;
+      }
+      if (schema instanceof Array) {
+        return;
+      }
+      return virtual(schema);
+    }
+  });
     return Schema;
   }
   var root = create();
diff --git a/jpacks.min.js b/jpacks.min.js
index 1e1ab54..d12da33 100644
--- a/jpacks.min.js
+++ b/jpacks.min.js
@@ -1 +1 @@
-!function(r){function n(){function r(r){var n=this;Object.keys(r).forEach(function(e){n[e]=r[e]})}function n(r){r=r||{},Object.keys(r).forEach(function(n){f[n]=r[n]})}function e(r){if(r instanceof ArrayBuffer)return r;var n=new ArrayBuffer(r.length),e=new Uint8Array(n,0,r.length);return e.set(r),n}function t(n,t,a,i){var u=r.from(n);if(!u)throw new Error('Parameter schema "'+n+'" is unregister.');return t=e(t),a=a||{},i=i||[0],Object.keys(f).forEach(function(r){"undefined"==typeof a[r]&&(a[r]=f[r])}),u.unpack(t,a,i)}function a(n,e,t,a){var i=r.from(n);if(!i)throw new Error('Parameter schema "'+n+'" is unregister.');return a=a||[],t=t||{},Object.keys(f).forEach(function(r){"undefined"==typeof t[r]&&(t[r]=f[r])}),i.pack(e,t,a),a}function i(r,n,e){if(r.length<=0)return r;var t=function(){var t=[];if([].push.apply(t,e),[].push.apply(t,arguments),t.length>=r.length)return r.apply(null,t);var a=i(r,n,t);return"function"==typeof n&&n(a,t),a};return t}function u(n){function e(n){if(!n)return 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\ No newline at end of file
+!function(r){function n(){function r(r){var n=this;Object.keys(r).forEach(function(e){n[e]=r[e]})}function n(r){r=r||{},Object.keys(r).forEach(function(n){f[n]=r[n]})}function e(r){if(r instanceof ArrayBuffer)return r;var n=new ArrayBuffer(r.length),e=new Uint8Array(n,0,r.length);return e.set(r),n}function t(n,t,a,i){var u=r.from(n);if(!u)throw new Error('Parameter schema "'+n+'" is unregister.');return t=e(t),a=a||{},i=i||[0],Object.keys(f).forEach(function(r){"undefined"==typeof a[r]&&(a[r]=f[r])}),u.unpack(t,a,i)}function a(n,e,t,a){var i=r.from(n);if(!i)throw new Error('Parameter schema "'+n+'" is unregister.');return a=a||[],t=t||{},Object.keys(f).forEach(function(r){"undefined"==typeof t[r]&&(t[r]=f[r])}),i.pack(e,t,a),a}function i(r,n,e){if(r.length<=0)return r;var t=function(){var t=[];if([].push.apply(t,e),[].push.apply(t,arguments),t.length>=r.length)return r.apply(null,t);var a=i(r,n,t);return"function"==typeof n&&n(a,t),a};return t}function u(n){function e(n){if(!n)return n;if(n.namespace)return"number"===n.namespace?"'"+n.name+"'":n.args?n.namespace+"("+u.apply(null,n.args)+")":"'"+n.namespace+"'";if("function"==typeof n)n.name||(n.name="_pack_fn"+s++,r.define(n.name,n));else if("object"==typeof n){var t=new n.constructor;return Object.keys(n).forEach(function(r){t[r]=e(n[r])}),t}return n.name?"'"+n.name+"'":"string"==typeof n?"'"+n+"'":n}if(arguments.length>1){for(var t=[],a=0;a<arguments.length;a++)t.push(u(arguments[a]));return t.join()}return JSON.stringify(e(n)||"").replace(/"/g,"")}var o={};r.register=function(n,e){o[n]=e,r[n]||(r[n]=e)},r.def=r.register;var c=[function(r){for(var n={},e=r;"string"==typeof e;){if(n[e])return;e=o[e],n[e]=!0}return e}];r.pushPattern=function(r){c.push(r)},r.from=function(n){if(n instanceof r)return n;for(var e=-1,t=0;t<c.length;t++)if(e!==t){var a=c[t](n);if(a){if(a instanceof r)return a;n=a,e=t,t=0}}};var f={littleEndian:!0};r.setDefaultOptions=n,r.arrayBufferFrom=e,r.unpack=t,r.pack=a,r.together=i;var s=0;return r.stringify=u,r.prototype.toString=function(){return u(this)},r}function e(){function r(r,n){var e,t;return"number"==typeof n?e=r.size*n:t=k.from(n),new k({unpack:function(a,i,u){var o=n;if(t&&(o=k.unpack(t,a,i,u)),r.array&&i.littleEndian){e=t.size*o;var c=u[0];return u[0]+=e,[].slice.apply(new r.array(a,c,o))}for(var f=[],s=0;o>s;s++)f.push(k.unpack(r,a,i,u));return f},pack:function(a,i,u){var o=n;if(t&&(o=a?a.length:0,k.pack(t,o,i,u)),r.array&&i.littleEndian){e=r.size*o;var c=new ArrayBuffer(e),f=new r.array(c);f.set(a);var s=new Uint8Array(c);[].push.apply(u,s)}for(var p=0;o>p;p++)k.pack(r,(a||[])[p],i,u)},namespace:"array",args:arguments,size:e})}function e(r){return A(r,"uint8")}function t(r){return A(r,"uint16")}function a(r){return A(r,"uint32")}function i(r){return k.array("uint8",r)}function u(r){if(r instanceof k)return r;var n=Object.keys(r);return new k({unpack:function(e,t,a){var i=new r.constructor,u=t.$scope;return t.$scope=i,n.forEach(function(n){i[n]=k.unpack(r[n],e,t,a)}),t.$scope=u,i},pack:function(e,t,a){var i=t.$scope;t.$scope=e,n.forEach(function(n){k.pack(r[n],e[n],t,a)}),t.$scope=i},args:arguments,namespace:"object"})}function o(r,n){var e=Object.keys(r);return new k({unpack:function(t,a,i){var u=i[0],o={};return e.forEach(function(n){i[0]=u,o[n]=k.unpack(r[n],t,a,i)}),i[0]+=n,o},pack:function(t,a,i){var u=new ArrayBuffer(n),o=new Uint8Array(u);e.forEach(function(n){if("undefined"!=typeof t[n]){var e=[];k.pack(r[n],t[n],a,e),o.set(e)}}),[].push.apply(i,o)},size:n,args:arguments,namespace:"union"})}function c(r,n){if(n=k.from(n),r instanceof Array){var e={};r.forEach(function(r,n){e[r]=n}),r=e}var t=Object.keys(r);return new k({unpack:function(e,a,i){var u,o=k.unpack(n,e,a,i);return t.every(function(n){return r[n]===o?(u=n,!1):!0}),u||o},pack:function(e,a,i){if("number"==typeof e)return void k.pack(n,e,a,i);if(t.every(function(t){return t===e?(k.pack(n,r[t],a,i),!1):!0}))throw new Error('Not find enum "'+e+'".')},namespace:"enums",args:arguments})}function f(r){return String(r).replace(/[\u0080-\u07ff]/g,function(r){var n=r.charCodeAt(0);return String.fromCharCode(192|n>>6,128|63&n)}).replace(/[\u0800-\uffff]/g,function(r){var n=r.charCodeAt(0);return String.fromCharCode(224|n>>12,128|n>>6&63,128|63&n)})}function s(r){return String(r).replace(/[\u00c0-\u00df][\u0080-\u00bf]/g,function(r){var n=(31&r.charCodeAt(0))<<6|63&r.charCodeAt(1);return String.fromCharCode(n)}).replace(/[\u00e0-\u00ef][\u0080-\u00bf][\u0080-\u00bf]/g,function(r){var n=(15&r.charCodeAt(0))<<12|(63&r.charCodeAt(1))<<6|63&r.charCodeAt(2);return String.fromCharCode(n)})}function p(r,n){return n.browser||"undefined"==typeof Buffer?f(r).split("").map(function(r){return r.charCodeAt()}):new Buffer(r,n.encoding)}function g(r){var n=k.array("uint8",r);return new k({unpack:function(r,e,t){var a=k.unpack(n,r,e,t);return e.browser||"undefined"==typeof Buffer?s(String.fromCharCode.apply(String,a)):new Buffer(a).toString(e.encoding)},pack:function(r,e,t){k.pack(n,p(r,e),e,t)},namespace:"string",args:arguments})}function y(r){return new k({unpack:function(n,e,t){var a;a=r===!0?new Uint8Array(n,t[0]):k.unpack(k.bytes(r),n,e,t);for(var i=0;a[i];)i++;var u=k.unpack(k.string(i),a,e);return r===!0&&(t[0]+=i+1),u},pack:function(n,e,t){var a=[0];[].unshift.apply(a,k.stringBytes(n,e)),r===!0?k.pack(k.bytes(a.length),a,e,t):k.pack(k.bytes(r),a,e,t)},namespace:"cstring",args:arguments})}function l(r,n){for(var e=0;e<r.length;e++)if(r[e][0]===n)return r[e][1]}function m(r,n){return new k({unpack:function(e,t,a){if(!t.$scope)throw new Error("Unpack must running in object.");var i=t.$scope[r];if("undefined"==typeof i)throw new Error('Field "'+r+'" is undefined.');return k.unpack(n(i),e,t,a)},pack:function(e,t,a){var i=t.$scope[r];if("undefined"==typeof i)throw new Error('Field "'+r+'" is undefined.');k.pack(n(i),e,t,a)},namespace:"depend",args:arguments})}function v(r,n){return B(r,k.array(n))}function h(r,n,e,t){var a=k.bytes(t);return new k({unpack:function(r,t,i){var u=n(k.unpack(a,r,t,i));return k.unpack(e,u,t)},pack:function(n,t,i){var u=r(k.pack(e,n,t));k.pack(a,u,t,i)},namespace:"parse",args:arguments})}function d(r,n){return new k({unpack:function(){return/string|number/.test(typeof r)?r+n:"function"==typeof r?r(n):n},pack:function(){},args:arguments,namespace:"virtual"})}var k=n(),w={int8:{type:"Int8",size:1,alias:["shortint"],array:Int8Array},uint8:{type:"Uint8",size:1,alias:["byte"],array:Uint8Array},int16:{type:"Int16",size:2,alias:["smallint"],array:Int16Array},uint16:{type:"Uint16",size:2,alias:["word"],array:Uint16Array},int32:{type:"Int32",size:4,alias:["longint"],array:Int32Array},uint32:{type:"Uint32",size:4,alias:["longword"],array:Uint32Array},float32:{type:"Float32",size:4,alias:["single"],array:Float32Array},float64:{type:"Float64",size:8,alias:["double"],array:Float64Array}};Object.keys(w).forEach(function(r){var n=w[r],e=new k({unpack:function(r){return function(e,t,a){var i=a[0];a[0]+=n.size;var u;return u=e instanceof DataView?e:new DataView(e),u[r](i,t.littleEndian)}}("get"+n.type),pack:function(r){return function(e,t,a){var i=new ArrayBuffer(n.size),u=new DataView(i),o=new Uint8Array(i);u[r](0,e,t.littleEndian),[].push.apply(a,o)}}("set"+n.type),size:n.size,name:r,namespace:"number",array:n.array});k.register(r,e),(n.alias||[]).forEach(function(r){k.register(r,e)})});var A=k.together(r,function(r,n){r.namespace="array",r.args=n});k.register("array",A),k.register("shortArray",e),k.register("smallArray",t),k.register("longArray",a),k.register("bytes",i);var b=k.together(u,function(r,n){r.namespace="object",r.args=n});k.register("object",b),k.pushPattern(function(r){if("object"==typeof r){if(r instanceof k)return;if(r instanceof Array)return;return b(r)}});var E=k.together(o,function(r,n){r.namespace="union",r.args=n});k.register("union",E);var C=k.together(c,function(r,n){r.namespace="enums",r.args=n});k.register("enums",C),k.stringBytes=p;var j=k.together(g,function(r,n){r.namespace="string",r.args=n});k.register("string",j),k.register("shortString",j("uint8")),k.register("smallString",j("uint16")),k.register("longString",j("uint32"));var z=k.together(y,function(r,n){r.namespace="cstring",r.args=n});k.register("cstring",z),k.register("pchar",z(!0));var S=k.together(l,function(r,n){r.namespace="cases",r.args=n});k.register("cases",S);var B=k.together(m,function(r,n){r.namespace="depend",r.args=n});k.register("depend",B),k.register("dependArray",v);var U=k.together(h,function(r,n){r.namespace="parse",r.args=n});k.register("parse",U);var O=k.together(d,function(r,n){r.namespace="virtual",r.args=n});return k.register("virtual",O),k.pushPattern(function(r){if("virtual"==typeof r){if(r instanceof k)return;if(r instanceof Array)return;return O(r)}}),k}var t=e();t.create=e;var a=t;"function"==typeof define?(define.amd||define.cmd)&&define(function(){return a}):"undefined"!=typeof module&&module.exports?module.exports=a:window[r]=a}("jpacks");
\ No newline at end of file
diff --git a/package.json b/package.json
index ed86095..84a94e9 100644
--- a/package.json
+++ b/package.json
@@ -2,9 +2,9 @@
   "name": "jpacks",
   "title": "c struct packer",
   "description": "Binary data packing and unpacking.",
-  "version": "0.3.13",
+  "version": "0.3.15",
   "homepage": "http://github.com/zswang/jpacks",
-  "main": "src/jpacks.js",
+  "main": "jpacks.js",
   "author": {
     "name": "zswang",
     "url": "http://weibo.com/zswang"
diff --git a/schemas-extend/bigint.js b/schemas-extend/bigint.js
index 4d884ff..22e217b 100644
--- a/schemas-extend/bigint.js
+++ b/schemas-extend/bigint.js
@@ -26,7 +26,7 @@ module.exports = function(Schema) {
     var _ = jpacks;
     var _schema = _.uint64;
     console.log(_.stringify(_schema))
-    // > uint64
+    // > 'uint64'
 
     var buffer = _.pack(_schema, '1609531171697315243');
 
@@ -41,7 +41,7 @@ module.exports = function(Schema) {
     var _ = jpacks;
     var _schema = _.uint64;
     console.log(_.stringify(_schema))
-    // > uint64
+    // > 'uint64'
 
     var buffer = _.pack(_schema, 171697315);
 
@@ -56,7 +56,7 @@ module.exports = function(Schema) {
     var _ = jpacks;
     var _schema = _.uint64;
     console.log(_.stringify(_schema))
-    // > uint64
+    // > 'uint64'
 
     var buffer = _.pack(_schema, 171697315, { littleEndian: false });
 
@@ -71,7 +71,7 @@ module.exports = function(Schema) {
     var _ = jpacks;
     var _schema = _.int64;
     console.log(_.stringify(_schema))
-    // > int64
+    // > 'int64'
 
     var buffer = _.pack(_schema, '-1');
 
@@ -94,7 +94,7 @@ module.exports = function(Schema) {
     var _ = jpacks;
     var _schema = _.int64;
     console.log(_.stringify(_schema))
-    // > int64
+    // > 'int64'
 
     var buffer = _.pack(_schema, -2, { littleEndian: false });
 
diff --git a/schemas-extend/protobuf.js b/schemas-extend/protobuf.js
index 55244ff..60bf895 100644
--- a/schemas-extend/protobuf.js
+++ b/schemas-extend/protobuf.js
@@ -61,7 +61,7 @@ module.exports = function(Schema) {
    * @param {Object} json JSON 数据
    */
   function jsonify(messager, json, options) {
-    if (!json) {
+    if (!json || !messager) {
       return;
     }
     var type = messager.$type;
@@ -122,7 +122,7 @@ module.exports = function(Schema) {
       'int8'
     );
     console.log(_.stringify(_schema))
-    // > array(protobuf(test/protoify/json.proto,js.Value,uint16),int8)
+    // > array(protobuf('test/protoify/json.proto','js.Value','uint16'),'int8')
 
     var buffer = _.pack(_schema, [{
       integer: 123
@@ -155,7 +155,7 @@ module.exports = function(Schema) {
       'int8'
     );
     console.log(_.stringify(_schema))
-    // > array(protobuf(test/protoify/bigint.proto,bigint.Value,uint16),int8)
+    // > array(protobuf('test/protoify/bigint.proto','bigint.Value','uint16'),'int8')
 
     var buffer = _.pack(_schema, [{
       int64: "-192377746236123"
@@ -177,7 +177,7 @@ module.exports = function(Schema) {
       'int8'
     );
     console.log(_.stringify(_schema))
-    // > array(protobuf(test/protoify/string.proto,str.Value,uint16),int8)
+    // > array(protobuf('test/protoify/string.proto','str.Value','uint16'),'int8')
 
     _.setDefaultOptions({
       protobuf_bytesAsString: true
diff --git a/schemas-extend/zlib.js b/schemas-extend/zlib.js
index e259989..9e225fa 100644
--- a/schemas-extend/zlib.js
+++ b/schemas-extend/zlib.js
@@ -16,15 +16,17 @@ module.exports = function(Schema) {
       data: _.gzip(_.shortString, 'uint16')
     });
     console.log(_.stringify(_schema))
-    // > object({type:uint8,data:parse(zlib.gzipSync,zlib.gunzipSync,string(uint8),uint16)})
+    // > object({type:'uint8',data:parse('zlib.gzipSync','zlib.gunzipSync',string('uint8'),'uint16')})
 
     var buffer = _.pack(_schema, {
       type: 2,
       data: '你好世界！Hello'
     });
 
-    console.log(buffer.join(' '));
-    // > 2 42 0 31 139 8 0 0 0 0 0 0 3 19 121 178 119 193 211 165 123 159 236 152 246 124 106 207 251 61 141 30 169 57 57 249 0 183 181 133 147 21 0 0 0
+    console.log(buffer.slice(14).join(' '));
+    // windows: 2 42 0 31 139 8 0 0 0 0 0 0 11 19 121 178 119 193 211 165 123 159 236 152 246 124 106 207 251 61 141 30 169 57 57 249 0 183 181 133 147 21 0 0 0
+    // linux:   2 42 0 31 139 8 0 0 0 0 0 0 3 19 121 178 119 193 211 165 123 159 236 152 246 124 106 207 251 61 141 30 169 57 57 249 0 183 181 133 147 21 0 0 0
+    // > 121 178 119 193 211 165 123 159 236 152 246 124 106 207 251 61 141 30 169 57 57 249 0 183 181 133 147 21 0 0 0
 
     console.log(JSON.stringify(_.unpack(_schema, buffer)));
     // > {"type":2,"data":"你好世界！Hello"}
@@ -63,7 +65,7 @@ module.exports = function(Schema) {
       data: _.inflate(_.shortString, 'uint16')
     });
     console.log(_.stringify(_schema))
-    // > object({type:uint8,data:parse(zlib.deflateSync,zlib.inflateSync,string(uint8),uint16)})
+    // > object({type:'uint8',data:parse('zlib.deflateSync','zlib.inflateSync',string('uint8'),'uint16')})
 
     var buffer = _.pack(_schema, {
       type: 2,
diff --git a/src/jpacks.js b/src/jpacks.js
index 45d697c..2246086 100644
--- a/src/jpacks.js
+++ b/src/jpacks.js
@@ -51,6 +51,8 @@
     require('./schemas/cases')(Schema);
     require('./schemas/depend')(Schema);
     require('./schemas/parse')(Schema);
+
+    require('./schemas/virtual')(Schema);
     /*</jdists>*/
 
     return Schema;
diff --git a/src/schema.js b/src/schema.js
index 0d00ca5..1356b67 100644
--- a/src/schema.js
+++ b/src/schema.js
@@ -31,7 +31,7 @@ function createSchema() {
    */
   function Schema(options) {
     var self = this;
-    Object.keys(options).forEach(function (key) {
+    Object.keys(options).forEach(function(key) {
       self[key] = options[key];
     });
   }
@@ -43,7 +43,7 @@ function createSchema() {
    * @param {Schema|string|Function} schema 数据结构或者数据结构名
    * @return {boolean} 返回是否定义成功
    */
-  Schema.register = function (name, schema) {
+  Schema.register = function(name, schema) {
     /*<safe>*/
     if (typeof name === 'undefined') {
       throw new Error('Parameter "name" is undefined.');
@@ -90,7 +90,7 @@ function createSchema() {
    *   function _pattern(schema) {}
    * ]]]
    */
-  Schema.pushPattern = function (pattern) {
+  Schema.pushPattern = function(pattern) {
     /*<safe>*/
     if (typeof pattern !== 'function') {
       return;
@@ -105,7 +105,7 @@ function createSchema() {
    * @param {string|Object|Schema} schema 数据结构名
    * @return {Schema} 返回名字对应的数据结构
    */
-  Schema.from = function (schema) {
+  Schema.from = function(schema) {
     /*<safe>*/
     if (typeof schema === 'undefined') { // 无效数据
       return;
@@ -147,7 +147,7 @@ function createSchema() {
    */
   function setDefaultOptions(options) {
     options = options || {};
-    Object.keys(options).forEach(function (key) {
+    Object.keys(options).forEach(function(key) {
       defaultOptions[key] = options[key];
     });
   }
@@ -190,7 +190,7 @@ function createSchema() {
     buffer = arrayBufferFrom(buffer); // 确保是 ArrayBuffer 类型
     options = options || {};
     offsets = offsets || [0];
-    Object.keys(defaultOptions).forEach(function (key) {
+    Object.keys(defaultOptions).forEach(function(key) {
       if (typeof options[key] === 'undefined') {
         options[key] = defaultOptions[key];
       }
@@ -220,7 +220,7 @@ function createSchema() {
     buffer = buffer || [];
 
     options = options || {};
-    Object.keys(defaultOptions).forEach(function (key) {
+    Object.keys(defaultOptions).forEach(function(key) {
       if (typeof options[key] === 'undefined') {
         options[key] = defaultOptions[key];
       }
@@ -311,43 +311,49 @@ function createSchema() {
       }
       return result.join();
     }
+
     function scan(obj) {
+      // if (obj === null) {
+      //   return 'null';
+      // }
       if (!obj) {
         return obj;
       }
       if (obj.namespace) {
         if (obj.namespace === 'number') {
-          return obj.name;
+          return "'" + obj.name + "'";
         }
         if (obj.args) {
           return obj.namespace + '(' + stringify.apply(null, obj.args) + ')';
         }
-        return obj.namespace;
-      }
-
-      if (obj.name) {
-        return obj.name;
+        return "'" + obj.namespace + "'";
       }
 
       if (typeof obj === 'function') {
-        obj.name = '_pack_fn' + (guid++);
-        Schema.define(obj.name, obj);
-        return obj.name;
-      }
-      if (typeof obj === 'object') {
+        if (!obj.name) {
+          obj.name = '_pack_fn' + (guid++);
+          Schema.define(obj.name, obj);
+        }
+      } else if (typeof obj === 'object') {
         var result = new obj.constructor();
-        Object.keys(obj).forEach(function (key) {
+        Object.keys(obj).forEach(function(key) {
           result[key] = scan(obj[key]);
         });
         return result;
       }
+      if (obj.name) {
+        return "'" + obj.name + "'";
+      }
+      if (typeof obj === 'string') {
+        return "'" + obj + "'";
+      }
       return obj;
     }
     return JSON.stringify(scan(obj) || '').replace(/"/g, '');
   }
   Schema.stringify = stringify;
 
-  Schema.prototype.toString = function () {
+  Schema.prototype.toString = function() {
     return stringify(this);
   };
   return Schema;
diff --git a/src/schemas/array.js b/src/schemas/array.js
index 2db75c4..88ac7e1 100644
--- a/src/schemas/array.js
+++ b/src/schemas/array.js
@@ -12,7 +12,7 @@ module.exports = function (Schema) {
     var _ = jpacks;
     var _schema = jpacks.array('int16', 2);
     console.log(String(_schema));
-    // > array(int16,2)
+    // > array('int16',2)
 
     var value = [12337, 12851];
     var buffer = jpacks.pack(_schema, value);
@@ -27,7 +27,7 @@ module.exports = function (Schema) {
     var _ = jpacks;
     var _schema = jpacks.array('int16', 'int8');
     console.log(String(_schema));
-    // > array(int16,int8)
+    // > array('int16','int8')
 
     var value = [12337, 12851];
     var buffer = jpacks.pack(_schema, value);
@@ -42,7 +42,7 @@ module.exports = function (Schema) {
     var _ = jpacks;
     var _schema = jpacks.array('int16')(6);
     console.log(String(_schema));
-    // > array(int16,6)
+    // > array('int16',6)
 
     var value = [12337, 12851];
     var buffer = jpacks.pack(_schema, value);
@@ -70,11 +70,6 @@ module.exports = function (Schema) {
       size = itemSchema.size * count;
     } else {
       countSchema = Schema.from(count);
-      /*<safe>*/
-      if (countSchema.namespace !== 'number') {
-        throw new Error('Parameter "count" is not a numeric type.');
-      }
-      /*</safe>*/
     }
 
     return new Schema({
diff --git a/src/schemas/bytes.js b/src/schemas/bytes.js
index f44ea84..d594f05 100644
--- a/src/schemas/bytes.js
+++ b/src/schemas/bytes.js
@@ -11,7 +11,7 @@ module.exports = function (Schema) {
     var _ = jpacks;
     var _schema = jpacks.bytes(6);
     console.log(String(_schema));
-    // > array(uint8,6)
+    // > array('uint8',6)
 
     var value = [0, 1, 2, 3, 4, 5];
     var buffer = jpacks.pack(_schema, value);
diff --git a/src/schemas/cases.js b/src/schemas/cases.js
index d56b18f..eb415cf 100644
--- a/src/schemas/cases.js
+++ b/src/schemas/cases.js
@@ -17,7 +17,7 @@ module.exports = function (Schema) {
       ]))
     };
     console.log(_.stringify(_schema));
-    // > {type:string(uint8),data:depend(type,cases([[name,string(uint8)],[age,uint8]]))}
+    // > {type:string('uint8'),data:depend('type',cases([['name',string('uint8')],['age','uint8']]))}
 
     var buffer = _.pack(_schema, {
       type: 'name',
diff --git a/src/schemas/cstring.js b/src/schemas/cstring.js
index c07f3b1..d8686ca 100644
--- a/src/schemas/cstring.js
+++ b/src/schemas/cstring.js
@@ -25,7 +25,7 @@ module.exports = function(Schema) {
     var _ = jpacks;
     var _schema = _.array(_.pchar, 'uint8');
     console.log(_.stringify(_schema));
-    // > array(cstring(true),uint8)
+    // > array(cstring(true),'uint8')
 
     var buffer = _.pack(_schema, ['abc', 'defghijk', 'g']);
     console.log(buffer.join(' '));
diff --git a/src/schemas/depend.js b/src/schemas/depend.js
index c7fea84..e22093e 100644
--- a/src/schemas/depend.js
+++ b/src/schemas/depend.js
@@ -11,7 +11,7 @@ module.exports = function (Schema) {
    *    function schemaCreator(value) {}
    * ]]]
    '''<example>'''
-   * @example dependCreator()
+   * @example dependCreator():base
     ```js
     var _ = jpacks;
     var _schema = _.object({
@@ -21,7 +21,7 @@ module.exports = function (Schema) {
       data2: _.depend('length2', _.array(_.shortString))
     });
     console.log(_.stringify(_schema));
-    // > object({length1:int8,length2:int8,data1:depend(length1,bytes),data2:depend(length2,array(string(uint8)))})
+    // > object({length1:'int8',length2:'int8',data1:depend('length1','bytes'),data2:depend('length2',array(string('uint8')))})
 
     var buffer = _.pack(_schema, {
       length1: 2,
diff --git a/src/schemas/enums.js b/src/schemas/enums.js
index 2226b69..a9b53a2 100644
--- a/src/schemas/enums.js
+++ b/src/schemas/enums.js
@@ -12,7 +12,7 @@ module.exports = function (Schema) {
     var _ = jpacks;
     var _schema = _.enums(['Sun', 'Mon', 'Tues', 'Wed', 'Thur', 'Fri', 'Sat'], 'uint8');
     console.log(_.stringify(_schema));
-    // > enums({Sun:0,Mon:1,Tues:2,Wed:3,Thur:4,Fri:5,Sat:6},uint8)
+    // > enums({Sun:0,Mon:1,Tues:2,Wed:3,Thur:4,Fri:5,Sat:6},'uint8')
 
     var buffer = _.pack(_schema, 'Tues');
     console.log(buffer.join(' '));
@@ -33,7 +33,7 @@ module.exports = function (Schema) {
       NotFound: 404
     }, 'int8');
     console.log(_.stringify(_schema));
-    // > enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},int8)
+    // > enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},'int8')
 
     var buffer = _.pack(_schema, 'Unknown');
     console.log(buffer.join(' '));
@@ -53,7 +53,7 @@ module.exports = function (Schema) {
       NotFound: 404
     }, 'int8');
     console.log(_.stringify(_schema));
-    // > enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},int8)
+    // > enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},'int8')
 
     var buffer = _.pack(_schema, 2);
     console.log(buffer.join(' '));
diff --git a/src/schemas/number.js b/src/schemas/number.js
index 7084254..06bfe93 100644
--- a/src/schemas/number.js
+++ b/src/schemas/number.js
@@ -21,7 +21,7 @@ module.exports = function defineNumber(Schema) {
     });
     var _schema = _.union(_map, 8);
     console.log(_.stringify(_schema));
-    // > union({bytes:array(uint8,8),int8:int8,int16:int16,int32:int32,uint8:uint8,uint16:uint16,uint32:uint32,float32:float32,float64:float64,shortint:shortint,smallint:smallint,longint:longint,byte:byte,word:word,longword:longword},8)
+    // > union({bytes:array('uint8',8),int8:'int8',int16:'int16',int32:'int32',uint8:'uint8',uint16:'uint16',uint32:'uint32',float32:'float32',float64:'float64',shortint:'shortint',smallint:'smallint',longint:'longint',byte:'byte',word:'word',longword:'longword'},8)
 
     var buffer = _.pack(_schema, {
       bytes: [0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, 0x89]
diff --git a/src/schemas/object.js b/src/schemas/object.js
index 3d2f4a8..4aacd5e 100644
--- a/src/schemas/object.js
+++ b/src/schemas/object.js
@@ -11,7 +11,7 @@ module.exports = function (Schema) {
     var _ = jpacks;
     var _schema = _.object([_.shortString, _.word]);
     console.log(_.stringify(_schema));
-    // > object([string(uint8),uint16])
+    // > object([string('uint8'),'uint16'])
 
     var buffer = _.pack(_schema, ['zswang', 1978]);
     console.log(buffer.join(' '));
@@ -28,7 +28,7 @@ module.exports = function (Schema) {
       year: _.word
     });
     console.log(_.stringify(_schema));
-    // > object({namespace:string,args:{0:uint8}})
+    // > object({name:string('uint8'),year:'uint16'})
 
     var buffer = _.pack(_schema, {
         name: 'zswang',
diff --git a/src/schemas/parse.js b/src/schemas/parse.js
index 9239a1f..f480498 100644
--- a/src/schemas/parse.js
+++ b/src/schemas/parse.js
@@ -19,7 +19,7 @@ module.exports = function(Schema) {
     };
     var _schema = _.parse(_xor, _xor, 'float64', 8);
     console.log(_.stringify(_schema));
-    // > parse(_xor,_xor,float64,8)
+    // > parse('_xor','_xor','float64',8)
 
     var buffer = _.pack(_schema, 2.94296650666094e+189);
     console.log(buffer.join(' '));
diff --git a/src/schemas/string.js b/src/schemas/string.js
index 8404f9e..ba791a0 100644
--- a/src/schemas/string.js
+++ b/src/schemas/string.js
@@ -85,8 +85,6 @@ module.exports = function (Schema) {
     // > 228 189 160 229 165 189 228 184 150 231 149 140 239 188 129 72 101 108 108 111 0 0 0 0 0
     console.log(_.unpack(_schema, buffer));
     // > 你好世界！Hello
-   '''<example>'''
-   '''<example>'''
    * @example stringCreator():dynamic
     var _ = jpacks;
     var _schema = _.string('int8');
diff --git a/src/schemas/union.js b/src/schemas/union.js
index 3210765..793d713 100644
--- a/src/schemas/union.js
+++ b/src/schemas/union.js
@@ -15,7 +15,7 @@ module.exports = function (Schema) {
       content: _.shortString
     }, 20);
     console.log(_.stringify(_schema));
-    // > union({length:uint8,content:string(uint8)},20)
+    // > union({length:'uint8',content:string('uint8')},20)
 
     var buffer = _.pack(_schema, {
       content: '0123456789'
diff --git a/src/schemas/virtual.js b/src/schemas/virtual.js
new file mode 100644
index 0000000..c390867
--- /dev/null
+++ b/src/schemas/virtual.js
@@ -0,0 +1,117 @@
+module.exports = function (Schema) {
+  /*<define>*/
+  /**
+   * 定义一个虚拟结构
+   *
+   * @param {number|string} operator
+   * @param {object} value 数据结构
+   '''<example>'''
+   * @example virtualCreator:number
+    ```js
+    var _ = jpacks;
+    var _schema = _.object({
+      f1: 'uint16',
+      v1: _.depend('f1', _.virtual(-4))
+    });
+    console.log(_.stringify(_schema))
+    // > object({f1:'uint16',v1:depend('f1',virtual(-4))})
+
+    var buffer = _.pack(_schema, {
+      f1: 4
+    });
+
+    console.log(buffer.join(' '));
+    // > 4 0
+
+    console.log(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+    // > {"f1":1024,"v1":1020}
+    ```
+   * @example virtualCreator:string
+    ```js
+    var _ = jpacks;
+    var _schema = _.object({
+      name: _.shortString,
+      welcome: _.depend('name', _.virtual('Hello '))
+    });
+    console.log(_.stringify(_schema))
+    // > object({name:string('uint8'),welcome:depend('name',virtual('Hello '))})
+
+    var buffer = _.pack(_schema, {
+      name: 'World!'
+    });
+
+    console.log(buffer.join(' '));
+    // > 6 87 111 114 108 100 33
+
+    console.log(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+    // > {"name":"World!","welcome":"Hello World!"}
+    ```
+   * @example virtualCreator:depend
+    ```js
+    var _ = jpacks;
+    var _schema = _.object({
+      name: _.shortString,
+      welcome: _.depend('name', _.cases([
+        ['zswang', _.depend('name', _.virtual('Hello '))],
+        ['wang', _.depend('name', _.virtual('Hi '))]
+      ]))
+    });
+    console.log(_.stringify(_schema))
+    // > object({name:string('uint8'),welcome:depend('name',cases([['zswang',depend('name',virtual('Hello '))],['wang',depend('name',virtual('Hi '))]]))})
+
+    var buffer = _.pack(_schema, {
+      name: 'zswang'
+    });
+
+    console.log(buffer.join(' '));
+    // > 6 122 115 119 97 110 103
+
+    console.log(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+    // > {"name":"zswang","welcome":"Hello zswang"}
+
+    var buffer = _.pack(_schema, {
+      name: 'wang'
+    });
+
+    console.log(buffer.join(' '));
+    // > 4 119 97 110 103
+
+    console.log(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+    // > {"name":"wang","welcome":"Hi wang"}
+   ```
+   '''</example>'''
+   */
+  function virtualCreator(operator, value) {
+    return new Schema({
+      unpack: function _unpack() {
+        if (/string|number/.test(typeof operator)) {
+          return operator + value;
+        }
+        if (typeof operator === 'function') {
+          return operator(value);
+        }
+        return value;
+      },
+      pack: function _pack() {},
+      args: arguments,
+      namespace: 'virtual'
+    });
+  }
+  var virtual = Schema.together(virtualCreator, function (fn, args) {
+    fn.namespace = 'virtual';
+    fn.args = args;
+  });
+  Schema.register('virtual', virtual);
+  Schema.pushPattern(function _virtualPattern(schema) {
+    if (typeof schema === 'virtual') {
+      if (schema instanceof Schema) {
+        return;
+      }
+      if (schema instanceof Array) {
+        return;
+      }
+      return virtual(schema);
+    }
+  });
+  /*</define>*/
+};
diff --git a/test/example.js b/test/example.js
index 5e3b960..1f54d07 100644
--- a/test/example.js
+++ b/test/example.js
@@ -26,15 +26,15 @@ describe("./src/schema.js", function () {
     }
     var t = _.together(f);
     t(1)()(2, 3);
-    assert.equal(printValue, '[1,2,3]'); printValue = undefined;
+        assert.equal(printValue, "[1,2,3]"); printValue = undefined;
     t(4)(5)()(6);
-    assert.equal(printValue, '[4,5,6]'); printValue = undefined;
+        assert.equal(printValue, "[4,5,6]"); printValue = undefined;
     t(7, 8, 9);
-    assert.equal(printValue, '[7,8,9]'); printValue = undefined;
+        assert.equal(printValue, "[7,8,9]"); printValue = undefined;
     t('a', 'b')('c');
-    assert.equal(printValue, '["a","b","c"]'); printValue = undefined;
+        assert.equal(printValue, "[\"a\",\"b\",\"c\"]"); printValue = undefined;
     t()('x')()()('y')()()('z');
-    assert.equal(printValue, '["x","y","z"]'); printValue = undefined;
+        assert.equal(printValue, "[\"x\",\"y\",\"z\"]"); printValue = undefined;
   });
   it("together():hook", function () {
     var _ = jpacks;
@@ -43,7 +43,7 @@ describe("./src/schema.js", function () {
       t.schema = 'f(' + args + ')';
     });
     print(t(1)(2).schema);
-    assert.equal(printValue, 'f(1,2)'); printValue = undefined;
+        assert.equal(printValue, "f(1,2)"); printValue = undefined;
   });
 });
 describe("./src/schemas/array.js", function () {
@@ -52,37 +52,37 @@ describe("./src/schemas/array.js", function () {
     var _ = jpacks;
     var _schema = jpacks.array('int16', 2);
     print(String(_schema));
-    assert.equal(printValue, 'array(int16,2)'); printValue = undefined;
+        assert.equal(printValue, "array('int16',2)"); printValue = undefined;
     var value = [12337, 12851];
     var buffer = jpacks.pack(_schema, value);
     print(buffer.join(' '));
-    assert.equal(printValue, '49 48 51 50'); printValue = undefined;
+        assert.equal(printValue, "49 48 51 50"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '[12337,12851]'); printValue = undefined;
+        assert.equal(printValue, "[12337,12851]"); printValue = undefined;
   });
   it("arrayCreator():dynamic array", function () {
     var _ = jpacks;
     var _schema = jpacks.array('int16', 'int8');
     print(String(_schema));
-    assert.equal(printValue, 'array(int16,int8)'); printValue = undefined;
+        assert.equal(printValue, "array('int16','int8')"); printValue = undefined;
     var value = [12337, 12851];
     var buffer = jpacks.pack(_schema, value);
     print(buffer.join(' '));
-    assert.equal(printValue, '2 49 48 51 50'); printValue = undefined;
+        assert.equal(printValue, "2 49 48 51 50"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '[12337,12851]'); printValue = undefined;
+        assert.equal(printValue, "[12337,12851]"); printValue = undefined;
   });
   it("arrayCreator():dynamic array 2", function () {
     var _ = jpacks;
     var _schema = jpacks.array('int16')(6);
     print(String(_schema));
-    assert.equal(printValue, 'array(int16,6)'); printValue = undefined;
+        assert.equal(printValue, "array('int16',6)"); printValue = undefined;
     var value = [12337, 12851];
     var buffer = jpacks.pack(_schema, value);
     print(buffer.join(' '));
-    assert.equal(printValue, '49 48 51 50 0 0 0 0 0 0 0 0'); printValue = undefined;
+        assert.equal(printValue, "49 48 51 50 0 0 0 0 0 0 0 0"); printValue = undefined;
     print(JSON.stringify(jpacks.unpack(_schema, buffer)));
-    assert.equal(printValue, '[12337,12851,0,0,0,0]'); printValue = undefined;
+        assert.equal(printValue, "[12337,12851,0,0,0,0]"); printValue = undefined;
   });
 });
 describe("./src/schemas/bytes.js", function () {
@@ -91,13 +91,13 @@ describe("./src/schemas/bytes.js", function () {
     var _ = jpacks;
     var _schema = jpacks.bytes(6);
     print(String(_schema));
-    assert.equal(printValue, 'array(uint8,6)'); printValue = undefined;
+        assert.equal(printValue, "array('uint8',6)"); printValue = undefined;
     var value = [0, 1, 2, 3, 4, 5];
     var buffer = jpacks.pack(_schema, value);
     print(buffer.join(' '));
-    assert.equal(printValue, '0 1 2 3 4 5'); printValue = undefined;
+        assert.equal(printValue, "0 1 2 3 4 5"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '[0,1,2,3,4,5]'); printValue = undefined;
+        assert.equal(printValue, "[0,1,2,3,4,5]"); printValue = undefined;
   });
 });
 describe("./src/schemas/cases.js", function () {
@@ -112,23 +112,23 @@ describe("./src/schemas/cases.js", function () {
       ]))
     };
     print(_.stringify(_schema));
-    assert.equal(printValue, '{type:string(uint8),data:depend(type,cases([[name,string(uint8)],[age,uint8]]))}'); printValue = undefined;
+        assert.equal(printValue, "{type:string('uint8'),data:depend('type',cases([['name',string('uint8')],['age','uint8']]))}"); printValue = undefined;
     var buffer = _.pack(_schema, {
       type: 'name',
       data: 'tom'
     });
     print(buffer.join(' '));
-    assert.equal(printValue, '4 110 97 109 101 3 116 111 109'); printValue = undefined;
+        assert.equal(printValue, "4 110 97 109 101 3 116 111 109"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '{"type":"name","data":"tom"}'); printValue = undefined;
+        assert.equal(printValue, "{\"type\":\"name\",\"data\":\"tom\"}"); printValue = undefined;
     var buffer = _.pack(_schema, {
       type: 'age',
       data: 23
     });
     print(buffer.join(' '));
-    assert.equal(printValue, '3 97 103 101 23'); printValue = undefined;
+        assert.equal(printValue, "3 97 103 101 23"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '{"type":"age","data":23}'); printValue = undefined;
+        assert.equal(printValue, "{\"type\":\"age\",\"data\":23}"); printValue = undefined;
   });
 });
 describe("./src/schemas/cstring.js", function () {
@@ -137,28 +137,28 @@ describe("./src/schemas/cstring.js", function () {
     var _ = jpacks;
     var _schema = _.cstring(32);
     print(_.stringify(_schema));
-    assert.equal(printValue, 'cstring(32)'); printValue = undefined;
+        assert.equal(printValue, "cstring(32)"); printValue = undefined;
     var buffer = _.pack(_schema, 'Hello 你好！');
     print(buffer.join(' '));
-    assert.equal(printValue, '72 101 108 108 111 32 228 189 160 229 165 189 239 188 129 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0'); printValue = undefined;
+        assert.equal(printValue, "72 101 108 108 111 32 228 189 160 229 165 189 239 188 129 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '"Hello 你好！"'); printValue = undefined;
+        assert.equal(printValue, "\"Hello 你好！\""); printValue = undefined;
   });
   it("cstringCreator():pchar", function () {
     var _ = jpacks;
     var _schema = _.array(_.pchar, 'uint8');
     print(_.stringify(_schema));
-    assert.equal(printValue, 'array(cstring(true),uint8)'); printValue = undefined;
+        assert.equal(printValue, "array(cstring(true),'uint8')"); printValue = undefined;
     var buffer = _.pack(_schema, ['abc', 'defghijk', 'g']);
     print(buffer.join(' '));
-    assert.equal(printValue, '3 97 98 99 0 100 101 102 103 104 105 106 107 0 103 0'); printValue = undefined;
+        assert.equal(printValue, "3 97 98 99 0 100 101 102 103 104 105 106 107 0 103 0"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '["abc","defghijk","g"]'); printValue = undefined;
+        assert.equal(printValue, "[\"abc\",\"defghijk\",\"g\"]"); printValue = undefined;
   });
 });
 describe("./src/schemas/depend.js", function () {
   printValue = undefined;
-  it("dependCreator()", function () {
+  it("dependCreator():base", function () {
     var _ = jpacks;
     var _schema = _.object({
       length1: 'int8',
@@ -167,7 +167,7 @@ describe("./src/schemas/depend.js", function () {
       data2: _.depend('length2', _.array(_.shortString))
     });
     print(_.stringify(_schema));
-    assert.equal(printValue, 'object({length1:int8,length2:int8,data1:depend(length1,bytes),data2:depend(length2,array(string(uint8)))})'); printValue = undefined;
+        assert.equal(printValue, "object({length1:'int8',length2:'int8',data1:depend('length1','bytes'),data2:depend('length2',array(string('uint8')))})"); printValue = undefined;
     var buffer = _.pack(_schema, {
       length1: 2,
       length2: 3,
@@ -175,9 +175,9 @@ describe("./src/schemas/depend.js", function () {
       data2: ['甲', '乙', '丙']
     });
     print(buffer.join(' '));
-    assert.equal(printValue, '2 3 1 2 3 231 148 178 3 228 185 153 3 228 184 153'); printValue = undefined;
+        assert.equal(printValue, "2 3 1 2 3 231 148 178 3 228 185 153 3 228 184 153"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '{"length1":2,"length2":3,"data1":[1,2],"data2":["甲","乙","丙"]}'); printValue = undefined;
+        assert.equal(printValue, "{\"length1\":2,\"length2\":3,\"data1\":[1,2],\"data2\":[\"甲\",\"乙\",\"丙\"]}"); printValue = undefined;
   });
 });
 describe("./src/schemas/enums.js", function () {
@@ -186,12 +186,12 @@ describe("./src/schemas/enums.js", function () {
     var _ = jpacks;
     var _schema = _.enums(['Sun', 'Mon', 'Tues', 'Wed', 'Thur', 'Fri', 'Sat'], 'uint8');
     print(_.stringify(_schema));
-    assert.equal(printValue, 'enums({Sun:0,Mon:1,Tues:2,Wed:3,Thur:4,Fri:5,Sat:6},uint8)'); printValue = undefined;
+        assert.equal(printValue, "enums({Sun:0,Mon:1,Tues:2,Wed:3,Thur:4,Fri:5,Sat:6},'uint8')"); printValue = undefined;
     var buffer = _.pack(_schema, 'Tues');
     print(buffer.join(' '));
-    assert.equal(printValue, '2'); printValue = undefined;
+        assert.equal(printValue, "2"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '"Tues"'); printValue = undefined;
+        assert.equal(printValue, "\"Tues\""); printValue = undefined;
   });
   it("enumsCreator():map is object", function () {
     var _ = jpacks;
@@ -204,12 +204,12 @@ describe("./src/schemas/enums.js", function () {
       NotFound: 404
     }, 'int8');
     print(_.stringify(_schema));
-    assert.equal(printValue, 'enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},int8)'); printValue = undefined;
+        assert.equal(printValue, "enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},'int8')"); printValue = undefined;
     var buffer = _.pack(_schema, 'Unknown');
     print(buffer.join(' '));
-    assert.equal(printValue, '255'); printValue = undefined;
+        assert.equal(printValue, "255"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '"Unknown"'); printValue = undefined;
+        assert.equal(printValue, "\"Unknown\""); printValue = undefined;
   });
   it("enumsCreator():fault tolerant", function () {
     var _ = jpacks;
@@ -222,12 +222,12 @@ describe("./src/schemas/enums.js", function () {
       NotFound: 404
     }, 'int8');
     print(_.stringify(_schema));
-    assert.equal(printValue, 'enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},int8)'); printValue = undefined;
+        assert.equal(printValue, "enums({Unknown:-1,Continue:100,Processing:100,OK:200,Created:201,NotFound:404},'int8')"); printValue = undefined;
     var buffer = _.pack(_schema, 2);
     print(buffer.join(' '));
-    assert.equal(printValue, '2'); printValue = undefined;
+        assert.equal(printValue, "2"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '2'); printValue = undefined;
+        assert.equal(printValue, "2"); printValue = undefined;
 });
 describe("./src/schemas/number.js", function () {
   printValue = undefined;
@@ -240,14 +240,14 @@ describe("./src/schemas/number.js", function () {
     });
     var _schema = _.union(_map, 8);
     print(_.stringify(_schema));
-    assert.equal(printValue, 'union({bytes:array(uint8,8),int8:int8,int16:int16,int32:int32,uint8:uint8,uint16:uint16,uint32:uint32,float32:float32,float64:float64,shortint:shortint,smallint:smallint,longint:longint,byte:byte,word:word,longword:longword},8)'); printValue = undefined;
+        assert.equal(printValue, "union({bytes:array('uint8',8),int8:'int8',int16:'int16',int32:'int32',uint8:'uint8',uint16:'uint16',uint32:'uint32',float32:'float32',float64:'float64',shortint:'shortint',smallint:'smallint',longint:'longint',byte:'byte',word:'word',longword:'longword'},8)"); printValue = undefined;
     var buffer = _.pack(_schema, {
       bytes: [0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, 0x89]
     });
     print(buffer.join(' '));
-    assert.equal(printValue, '18 35 52 69 86 103 120 137'); printValue = undefined;
+        assert.equal(printValue, "18 35 52 69 86 103 120 137"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '{"bytes":[18,35,52,69,86,103,120,137],"int8":18,"int16":8978,"int32":1161044754,"uint8":18,"uint16":8978,"uint32":1161044754,"float32":2882.19189453125,"float64":-4.843717058781651e-263,"shortint":18,"smallint":8978,"longint":1161044754,"byte":18,"word":8978,"longword":1161044754}'); printValue = undefined;
+        assert.equal(printValue, "{\"bytes\":[18,35,52,69,86,103,120,137],\"int8\":18,\"int16\":8978,\"int32\":1161044754,\"uint8\":18,\"uint16\":8978,\"uint32\":1161044754,\"float32\":2882.19189453125,\"float64\":-4.843717058781651e-263,\"shortint\":18,\"smallint\":8978,\"longint\":1161044754,\"byte\":18,\"word\":8978,\"longword\":1161044754}"); printValue = undefined;
   });
 });
 describe("./src/schemas/object.js", function () {
@@ -256,12 +256,12 @@ describe("./src/schemas/object.js", function () {
     var _ = jpacks;
     var _schema = _.object([_.shortString, _.word]);
     print(_.stringify(_schema));
-    assert.equal(printValue, 'object([string(uint8),uint16])'); printValue = undefined;
+        assert.equal(printValue, "object([string('uint8'),'uint16'])"); printValue = undefined;
     var buffer = _.pack(_schema, ['zswang', 1978]);
     print(buffer.join(' '));
-    assert.equal(printValue, '6 122 115 119 97 110 103 186 7'); printValue = undefined;
+        assert.equal(printValue, "6 122 115 119 97 110 103 186 7"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '["zswang",1978]'); printValue = undefined;
+        assert.equal(printValue, "[\"zswang\",1978]"); printValue = undefined;
   });
   it("objectCreator:object", function () {
     var _ = jpacks;
@@ -270,15 +270,15 @@ describe("./src/schemas/object.js", function () {
       year: _.word
     });
     print(_.stringify(_schema));
-    assert.equal(printValue, 'object({namespace:string,args:{0:uint8}})'); printValue = undefined;
+        assert.equal(printValue, "object({name:string('uint8'),year:'uint16'})"); printValue = undefined;
     var buffer = _.pack(_schema, {
         name: 'zswang',
         year: 1978
       });
     print(buffer.join(' '));
-    assert.equal(printValue, '6 122 115 119 97 110 103 186 7'); printValue = undefined;
+        assert.equal(printValue, "6 122 115 119 97 110 103 186 7"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '{"name":"zswang","year":1978}'); printValue = undefined;
+        assert.equal(printValue, "{\"name\":\"zswang\",\"year\":1978}"); printValue = undefined;
   });
 });
 describe("./src/schemas/parse.js", function () {
@@ -292,12 +292,12 @@ describe("./src/schemas/parse.js", function () {
     };
     var _schema = _.parse(_xor, _xor, 'float64', 8);
     print(_.stringify(_schema));
-    assert.equal(printValue, 'parse(_xor,_xor,float64,8)'); printValue = undefined;
+        assert.equal(printValue, "parse('_xor','_xor','float64',8)"); printValue = undefined;
     var buffer = _.pack(_schema, 2.94296650666094e+189);
     print(buffer.join(' '));
-    assert.equal(printValue, '111 75 41 7 126 92 58 24'); printValue = undefined;
+        assert.equal(printValue, "111 75 41 7 126 92 58 24"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '2.94296650666094e+189'); printValue = undefined;
+        assert.equal(printValue, "2.94296650666094e+189"); printValue = undefined;
   });
 });
 describe("./src/schemas/string.js", function () {
@@ -312,14 +312,75 @@ describe("./src/schemas/union.js", function () {
       content: _.shortString
     }, 20);
     print(_.stringify(_schema));
-    assert.equal(printValue, 'union({length:uint8,content:string(uint8)},20)'); printValue = undefined;
+        assert.equal(printValue, "union({length:'uint8',content:string('uint8')},20)"); printValue = undefined;
     var buffer = _.pack(_schema, {
       content: '0123456789'
     });
     print(buffer.join(' '));
-    assert.equal(printValue, '10 48 49 50 51 52 53 54 55 56 57 0 0 0 0 0 0 0 0 0'); printValue = undefined;
+        assert.equal(printValue, "10 48 49 50 51 52 53 54 55 56 57 0 0 0 0 0 0 0 0 0"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '{"length":10,"content":"0123456789"}'); printValue = undefined;
+        assert.equal(printValue, "{\"length\":10,\"content\":\"0123456789\"}"); printValue = undefined;
+  });
+});
+describe("./src/schemas/virtual.js", function () {
+  printValue = undefined;
+  it("virtualCreator:number", function () {
+    var _ = jpacks;
+    var _schema = _.object({
+      f1: 'uint16',
+      v1: _.depend('f1', _.virtual(-4))
+    });
+    print(_.stringify(_schema))
+        assert.equal(printValue, "object({f1:'uint16',v1:depend('f1',virtual(-4))})"); printValue = undefined;
+    var buffer = _.pack(_schema, {
+      f1: 4
+    });
+    print(buffer.join(' '));
+        assert.equal(printValue, "4 0"); printValue = undefined;
+    print(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+        assert.equal(printValue, "{\"f1\":1024,\"v1\":1020}"); printValue = undefined;
+  });
+  it("virtualCreator:string", function () {
+    var _ = jpacks;
+    var _schema = _.object({
+      name: _.shortString,
+      welcome: _.depend('name', _.virtual('Hello '))
+    });
+    print(_.stringify(_schema))
+        assert.equal(printValue, "object({name:string('uint8'),welcome:depend('name',virtual('Hello '))})"); printValue = undefined;
+    var buffer = _.pack(_schema, {
+      name: 'World!'
+    });
+    print(buffer.join(' '));
+        assert.equal(printValue, "6 87 111 114 108 100 33"); printValue = undefined;
+    print(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+        assert.equal(printValue, "{\"name\":\"World!\",\"welcome\":\"Hello World!\"}"); printValue = undefined;
+  });
+  it("virtualCreator:depend", function () {
+    var _ = jpacks;
+    var _schema = _.object({
+      name: _.shortString,
+      welcome: _.depend('name', _.cases([
+        ['zswang', _.depend('name', _.virtual('Hello '))],
+        ['wang', _.depend('name', _.virtual('Hi '))]
+      ]))
+    });
+    print(_.stringify(_schema))
+        assert.equal(printValue, "object({name:string('uint8'),welcome:depend('name',cases([['zswang',depend('name',virtual('Hello '))],['wang',depend('name',virtual('Hi '))]]))})"); printValue = undefined;
+    var buffer = _.pack(_schema, {
+      name: 'zswang'
+    });
+    print(buffer.join(' '));
+        assert.equal(printValue, "6 122 115 119 97 110 103"); printValue = undefined;
+    print(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+        assert.equal(printValue, "{\"name\":\"zswang\",\"welcome\":\"Hello zswang\"}"); printValue = undefined;
+    var buffer = _.pack(_schema, {
+      name: 'wang'
+    });
+    print(buffer.join(' '));
+        assert.equal(printValue, "4 119 97 110 103"); printValue = undefined;
+    print(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
+        assert.equal(printValue, "{\"name\":\"wang\",\"welcome\":\"Hi wang\"}"); printValue = undefined;
   });
 });
 describe("./schemas-extend/bigint.js", function () {
@@ -328,61 +389,61 @@ describe("./schemas-extend/bigint.js", function () {
     var _ = jpacks;
     var _schema = _.uint64;
     print(_.stringify(_schema))
-    assert.equal(printValue, 'uint64'); printValue = undefined;
+        assert.equal(printValue, "'uint64'"); printValue = undefined;
     var buffer = _.pack(_schema, '1609531171697315243');
     print(buffer.join(' '));
-    assert.equal(printValue, '171 205 239 175 18 52 86 22'); printValue = undefined;
+        assert.equal(printValue, "171 205 239 175 18 52 86 22"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '"1609531171697315243"'); printValue = undefined;
+        assert.equal(printValue, "\"1609531171697315243\""); printValue = undefined;
   });
   it("uint64():number", function () {
     var _ = jpacks;
     var _schema = _.uint64;
     print(_.stringify(_schema))
-    assert.equal(printValue, 'uint64'); printValue = undefined;
+        assert.equal(printValue, "'uint64'"); printValue = undefined;
     var buffer = _.pack(_schema, 171697315);
     print(buffer.join(' '));
-    assert.equal(printValue, '163 228 59 10 0 0 0 0'); printValue = undefined;
+        assert.equal(printValue, "163 228 59 10 0 0 0 0"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '"171697315"'); printValue = undefined;
+        assert.equal(printValue, "\"171697315\""); printValue = undefined;
   });
   it("uint64():littleEndian = false;", function () {
     var _ = jpacks;
     var _schema = _.uint64;
     print(_.stringify(_schema))
-    assert.equal(printValue, 'uint64'); printValue = undefined;
+        assert.equal(printValue, "'uint64'"); printValue = undefined;
     var buffer = _.pack(_schema, 171697315, { littleEndian: false });
     print(buffer.join(' '));
-    assert.equal(printValue, '0 0 0 0 10 59 228 163'); printValue = undefined;
+        assert.equal(printValue, "0 0 0 0 10 59 228 163"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
-    assert.equal(printValue, '"171697315"'); printValue = undefined;
+        assert.equal(printValue, "\"171697315\""); printValue = undefined;
   });
   it("int64():-1,-2", function () {
     var _ = jpacks;
     var _schema = _.int64;
     print(_.stringify(_schema))
-    assert.equal(printValue, 'int64'); printValue = undefined;
+        assert.equal(printValue, "'int64'"); printValue = undefined;
     var buffer = _.pack(_schema, '-1');
     print(buffer.join(' '));
-    assert.equal(printValue, '255 255 255 255 255 255 255 255'); printValue = undefined;
+        assert.equal(printValue, "255 255 255 255 255 255 255 255"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '"-1"'); printValue = undefined;
+        assert.equal(printValue, "\"-1\""); printValue = undefined;
     var buffer = _.pack(_schema, '-2');
     print(buffer.join(' '));
-    assert.equal(printValue, '254 255 255 255 255 255 255 255'); printValue = undefined;
+        assert.equal(printValue, "254 255 255 255 255 255 255 255"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '"-2"'); printValue = undefined;
+        assert.equal(printValue, "\"-2\""); printValue = undefined;
   });
   it("int64():-2, littleEndian = false", function () {
     var _ = jpacks;
     var _schema = _.int64;
     print(_.stringify(_schema))
-    assert.equal(printValue, 'int64'); printValue = undefined;
+        assert.equal(printValue, "'int64'"); printValue = undefined;
     var buffer = _.pack(_schema, -2, { littleEndian: false });
     print(buffer.join(' '));
-    assert.equal(printValue, '255 255 255 255 255 255 255 254'); printValue = undefined;
+        assert.equal(printValue, "255 255 255 255 255 255 255 254"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer, { littleEndian: false })));
-    assert.equal(printValue, '"-2"'); printValue = undefined;
+        assert.equal(printValue, "\"-2\""); printValue = undefined;
   });
 });
 describe("./schemas-extend/protobuf.js", function () {
@@ -394,7 +455,7 @@ describe("./schemas-extend/protobuf.js", function () {
       'int8'
     );
     print(_.stringify(_schema))
-    assert.equal(printValue, 'array(protobuf(test/protoify/json.proto,js.Value,uint16),int8)'); printValue = undefined;
+        assert.equal(printValue, "array(protobuf('test/protoify/json.proto','js.Value','uint16'),'int8')"); printValue = undefined;
     var buffer = _.pack(_schema, [{
       integer: 123
     }, {
@@ -412,9 +473,9 @@ describe("./schemas-extend/protobuf.js", function () {
       }
     }]);
     print(buffer.join(' '));
-    assert.equal(printValue, '2 3 0 8 246 1 33 0 58 31 10 6 26 4 110 97 109 101 10 6 26 4 121 101 97 114 18 8 26 6 122 115 119 97 110 103 18 3 8 190 31'); printValue = undefined;
+        assert.equal(printValue, "2 3 0 8 246 1 33 0 58 31 10 6 26 4 110 97 109 101 10 6 26 4 121 101 97 114 18 8 26 6 122 115 119 97 110 103 18 3 8 190 31"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '[{"integer":123},{"object":{"keys":[{"string":"name"},{"string":"year"}],"values":[{"string":"zswang"},{"integer":2015}]}}]'); printValue = undefined;
+        assert.equal(printValue, "[{\"integer\":123},{\"object\":{\"keys\":[{\"string\":\"name\"},{\"string\":\"year\"}],\"values\":[{\"string\":\"zswang\"},{\"integer\":2015}]}}]"); printValue = undefined;
   });
   it("protobufCreator():bigint", function () {
     var _ = jpacks;
@@ -423,16 +484,16 @@ describe("./schemas-extend/protobuf.js", function () {
       'int8'
     );
     print(_.stringify(_schema))
-    assert.equal(printValue, 'array(protobuf(test/protoify/bigint.proto,bigint.Value,uint16),int8)'); printValue = undefined;
+        assert.equal(printValue, "array(protobuf('test/protoify/bigint.proto','bigint.Value','uint16'),'int8')"); printValue = undefined;
     var buffer = _.pack(_schema, [{
       int64: "-192377746236123"
     }, {
       uint64: "192377746236123"
     }]);
     print(buffer.join(' '));
-    assert.equal(printValue, '2 11 0 8 165 186 151 134 137 161 212 255 255 1 8 0 16 219 197 232 249 246 222 43'); printValue = undefined;
+        assert.equal(printValue, "2 11 0 8 165 186 151 134 137 161 212 255 255 1 8 0 16 219 197 232 249 246 222 43"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '[{"int64":"-192377746236123"},{"uint64":"192377746236123"}]'); printValue = undefined;
+        assert.equal(printValue, "[{\"int64\":\"-192377746236123\"},{\"uint64\":\"192377746236123\"}]"); printValue = undefined;
   });
   it("protobufCreator():bytesAsString", function () {
     var _ = jpacks;
@@ -441,7 +502,7 @@ describe("./schemas-extend/protobuf.js", function () {
       'int8'
     );
     print(_.stringify(_schema))
-    assert.equal(printValue, 'array(protobuf(test/protoify/string.proto,str.Value,uint16),int8)'); printValue = undefined;
+        assert.equal(printValue, "array(protobuf('test/protoify/string.proto','str.Value','uint16'),'int8')"); printValue = undefined;
     _.setDefaultOptions({
       protobuf_bytesAsString: true
     });
@@ -451,9 +512,9 @@ describe("./schemas-extend/protobuf.js", function () {
       bytes: "你好世界!Hello World!"
     }]);
     print(buffer.join(' '));
-    assert.equal(printValue, '2 27 0 10 25 72 101 108 108 111 32 87 111 114 108 100 33 228 189 160 229 165 189 228 184 150 231 149 140 33 27 0 18 25 228 189 160 229 165 189 228 184 150 231 149 140 33 72 101 108 108 111 32 87 111 114 108 100 33'); printValue = undefined;
+        assert.equal(printValue, "2 27 0 10 25 72 101 108 108 111 32 87 111 114 108 100 33 228 189 160 229 165 189 228 184 150 231 149 140 33 27 0 18 25 228 189 160 229 165 189 228 184 150 231 149 140 33 72 101 108 108 111 32 87 111 114 108 100 33"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '[{"string":"Hello World!你好世界!"},{"bytes":"你好世界!Hello World!"}]'); printValue = undefined;
+        assert.equal(printValue, "[{\"string\":\"Hello World!你好世界!\"},{\"bytes\":\"你好世界!Hello World!\"}]"); printValue = undefined;
   });
 });
 describe("./schemas-extend/zlib.js", function () {
@@ -465,15 +526,17 @@ describe("./schemas-extend/zlib.js", function () {
       data: _.gzip(_.shortString, 'uint16')
     });
     print(_.stringify(_schema))
-    assert.equal(printValue, 'object({type:uint8,data:parse(zlib.gzipSync,zlib.gunzipSync,string(uint8),uint16)})'); printValue = undefined;
+        assert.equal(printValue, "object({type:'uint8',data:parse('zlib.gzipSync','zlib.gunzipSync',string('uint8'),'uint16')})"); printValue = undefined;
     var buffer = _.pack(_schema, {
       type: 2,
       data: '你好世界！Hello'
     });
-    print(buffer.join(' '));
-    assert.equal(printValue, '2 42 0 31 139 8 0 0 0 0 0 0 3 19 121 178 119 193 211 165 123 159 236 152 246 124 106 207 251 61 141 30 169 57 57 249 0 183 181 133 147 21 0 0 0'); printValue = undefined;
+    print(buffer.slice(14).join(' '));
+    // windows: 2 42 0 31 139 8 0 0 0 0 0 0 11 19 121 178 119 193 211 165 123 159 236 152 246 124 106 207 251 61 141 30 169 57 57 249 0 183 181 133 147 21 0 0 0
+    // linux:   2 42 0 31 139 8 0 0 0 0 0 0 3 19 121 178 119 193 211 165 123 159 236 152 246 124 106 207 251 61 141 30 169 57 57 249 0 183 181 133 147 21 0 0 0
+        assert.equal(printValue, "121 178 119 193 211 165 123 159 236 152 246 124 106 207 251 61 141 30 169 57 57 249 0 183 181 133 147 21 0 0 0"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '{"type":2,"data":"你好世界！Hello"}'); printValue = undefined;
+        assert.equal(printValue, "{\"type\":2,\"data\":\"你好世界！Hello\"}"); printValue = undefined;
   });
   it("inflateCreator():base", function () {
     var _ = jpacks;
@@ -482,14 +545,14 @@ describe("./schemas-extend/zlib.js", function () {
       data: _.inflate(_.shortString, 'uint16')
     });
     print(_.stringify(_schema))
-    assert.equal(printValue, 'object({type:uint8,data:parse(zlib.deflateSync,zlib.inflateSync,string(uint8),uint16)})'); printValue = undefined;
+        assert.equal(printValue, "object({type:'uint8',data:parse('zlib.deflateSync','zlib.inflateSync',string('uint8'),'uint16')})"); printValue = undefined;
     var buffer = _.pack(_schema, {
       type: 2,
       data: '你好世界！Hello'
     });
     print(buffer.join(' '));
-    assert.equal(printValue, '2 30 0 120 156 19 121 178 119 193 211 165 123 159 236 152 246 124 106 207 251 61 141 30 169 57 57 249 0 152 20 12 247'); printValue = undefined;
+        assert.equal(printValue, "2 30 0 120 156 19 121 178 119 193 211 165 123 159 236 152 246 124 106 207 251 61 141 30 169 57 57 249 0 152 20 12 247"); printValue = undefined;
     print(JSON.stringify(_.unpack(_schema, buffer)));
-    assert.equal(printValue, '{"type":2,"data":"你好世界！Hello"}'); printValue = undefined;
+        assert.equal(printValue, "{\"type\":2,\"data\":\"你好世界！Hello\"}"); printValue = undefined;
   });
 });
diff --git a/version.jdists b/version.jdists
index 6786da7..c4773c0 100644
--- a/version.jdists
+++ b/version.jdists
@@ -1,4 +1,5 @@
 /*<jdists encoding='jhtmls' data='package.json' export='package.json'>*/
+ main = 'jpacks.js';
 version = version.replace(/\d+$/, function (value) {
   return parseInt(value) + 1;
 });