只有运行时期间存在源数据时，才会执行任何对可选源数据进行操作的转换，否则，将不会发生转换。

Any transformations operating over optional source data will only execute if the source data exists during runtime. Otherwise, the transformation will not occur.

youdao

在多数情况下这不会发生问题，但是当一个IDL无符号整数取值正好落在最高位所限制的取值范围中时，类型转换就会发生不匹配的错误。

In most situations this does not pose a problem but for the translation of an IDL unsigned integer type whose value falls inside the number range of its highest order bit there will be a mismatch.

youdao

这个转换只接受结构化的元素：从例如状态机或者活动的行为模型中不会发生任何生成的动作。

This transformation only accepts structural items: no generation takes place from behavior models such as state machines or activities.

youdao