Version 2.0 introduced the plugin architecture that is used for almost all the customizable functionality of Smarty. This includes:
2.0版本引入了被广泛应用于自定义Smarty功能的插件机制。它包括如下类型：
为了与旧有方式保持向后兼容，除资源插件外，保留了通过register_* API方式装载函数的 处理方法。如果你不是使用API方式而是使用直接修改类变量 $custom_funcs, $custom_mods 等的方法，那么你就需要修改你的程序了。或者使用API的方法，或者将你的自定义功能转换成插件。
Plugins are always loaded on demand. Only the specific modifiers, functions, resources, etc invoked in the templates scripts will be loaded. Moreover, each plugin is loaded only once, even if you have several different instances of Smarty running within the same request.
插件总在需要的时候被装载。只有在模板脚本里调用的特定修饰、函数、资源插件等会被装载。此外，即便在同一个请求中有几个不同的Smarty实体运行，每个插件也只被装载一次。
Pre/postfilters and output filters are a bit of a special case. Since they are not mentioned in the templates, they must be registered or loaded explicitly via API functions before the template is processed. The order in which multiple filters of the same type are executed depends on the order in which they are registered or loaded.
预/补过滤器插件和输出过滤器插件的装载方式有些不同。由于在模板中未被提及，它们必须在模板被处理前通过API函数明确地装入系统。同类型的多个过滤器插件依据被装载的次序先后不同分别先后执行。
The plugins directory can be a string containing a path or an array containing multiple paths. To install a plugin, simply place it in one of the directories and Smarty will use it automatically.
插件目录是包含一条路径信息的字符串或包含多条路径信息的字符串数组。安装插件的时候，将插件置于其中一个目录下，Smarty会自动识别使用。