To register the FunctionCall object, do the following.
若要注册FunctionCall对象，请执行以下步骤。
There is no need to implement all the functions defined in the FunctionCall interface.
没有必要实现FunctionCall接口中所定义的所有函数。
It also registers the FunctionCall object and each of the custom functions it supports.
该类还将注册FunctionCall对象以及它所支持的每个定制函数。
Inside the FunctionCall class, you must declare each of the custom functions you want to create.
在functioncall类的内部，必须声明要创建的每一个定制函数。
Calling the FunctionCall class constructor you created in the section, "Creating the sample FunctionCall class."
调用在“创建示例functioncall类”一节中所创建的functioncall类构造函数。
Usually, the FunctionCall class extends the pre-defined superclass FunctionCallImplBase and merely implements the necessary methods.
通常，FunctionCall类将扩展预定义的超类 FunctionCallImplBase并且仅实现必需的方法。
Because a FunctionCall class can contain more than one custom function, you should define a unique identification number for each custom function.
因为functioncall类可以包含一个以上的定制函数，所以应当为每个定制函数定义惟一的识别号。
This method is used for the instantiation of the FunctionCall object that contains the definition and realization of custom packages and functions.
该方法用于FunctionCall对象的实例化，包含定制包和函数的定义及实现。
If a FunctionName in a FunctionCall expression is not an NCName (i.e. if it contains a colon), then it is treated as a call to an extension function.
如果FunctionCall表达式中的FunctionName不是NCName(也就是说，如果它包含了一个冒号)，那么就将它当作是对扩展函数的调用。
If a FunctionName in a FunctionCall expression is not an NCName (i.e. if it contains a colon), then it is treated as a call to an extension function.
如果FunctionCall表达式中的FunctionName不是NCName(也就是说，如果它包含了一个冒号)，那么就将它当作是对扩展函数的调用。
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