在Haxe標準庫中的一些類適用于靜態擴展用法。下面的例子展示了StringTools的用法： > Several classes in the Haxe Standard Library are suitable for static extension usage. The next example shows the usage of StringTools: ~~~ using StringTools; class Main { static public function main() { "adc".replace("d", "b"); } } ~~~ String本身并沒有替換功能， using StringTools 靜態擴展提供了一個。通常，JavaScript輸出很好的顯式了這個轉換： > While String does not have a replace functionality by itself, the using StringTools static extension provides one. As usual, the JavaScript output nicely shows the transformation: ~~~ Main.main = function() { StringTools.replace("adc","d","b"); } ~~~ 如下Haxe標準庫中的類都是設計作為靜態擴展使用： > The following classes from the Haxe Standard Library are designed to be used as static extensions: **StringTools**：提供字符串的擴展功能，例如替換和去除空格。 **Lambda**：提供功能方法到可迭代對象。 **haxe.EnumTools**：提供類型信息功能到enum和它們的實例。 **haxe.macro.Tools**：為和宏有關的操作提供不同的擴展（查看 工具（第9.4節）） > **StringTools**: Provides extended functionality on strings, such as replacing or trimming. > **Lambda**: Provides functional methods on iterables. > **haxe.EnumTools**: Provides type information functionality on enums and their instances. > **haxe.macro.Tools**: Provides different extensions for working with macros (see Tools (Section 9.4)). **使用using** >[warning] **花絮**：使用using 自從using關鍵字被添加到語言中，討論某些 使用using的問題 或者 using的影響變得非常常見。在很多情況下的英語變得尷尬，所以手冊的作者決定把這個使用實際的功能稱呼：靜態擴展。 >[warning] **Trivia**: “using” using Since the using keyword was added to the language, it has been common to talk about certain problems with “using using” or the effect of “using using”. This makes for awkward English in many cases, so the author of this manual decided to call the feature by what it actually is: Static extension. **大意可能就是說，using是作為靜態擴展的關鍵字存在。如果本節標題使用 using using 會造成混淆。**