This will generate a function signature in the source code with the const qualifier for the selected parameter, once the transformation is executed.
这样，当转换执行的时候，将在源代码中为选定的参数生成带有常量修饰符的函数签名。
2
A parameter whose name is not prefixed by a context qualifier would be assumed to have global scope and refer to the higher level in the hierarchy (Application).