add docs for rt-virtual

README.md

@@ -148,6 +148,46 @@ define([
 });
 ```
 
+## rt-virtual
+This directive creates as a virtual node, which will not be rendered to the DOM, but can still be used as a root for directives, e.g. `rt-if` and `rt-repeat`.
+
+###### Sample:
+For instance, to repeat several nodes at once without a shared root for each instance:
+```html
+<ul>
+  <rt-virtual rt-repeat="n in [1,2,3]">
+    <li>{n}</li>
+    <li>{n*2}</li>
+  </virtual>
+</ul>
+```
+
+##### Compiled:
+```javascript
+define([
+    'react/addons',
+    'lodash'
+], function (React, _) {
+    'use strict';
+    function repeatN1(n, nIndex) {
+        return [
+            React.createElement('li', {}, n),
+            React.createElement('li', {}, n * 2)
+        ];
+    }
+    return function () {
+        return React.createElement.apply(this, [
+            'ul',
+            {},
+            _.map([
+                1,
+                2,
+                3
+            ], repeatN1.bind(this))
+        ]);
+    };
+});
+```
 ## rt-scope
 This directive creates a new JavaScript scope by creating a new method and invoking it with its current context. The syntax is `rt-scope="expr1 as var1; expr2 as var2`.
 This allows for a convenient shorthand to make the code more readable. It also helps to execute an expression only once per scope.