What to put in the index?
As explained earlier in this chapter, everything that can be given a name will have a corresponding entry in the index; moreover, by default, each element of the index can be referred through its fully qualified name. However, only the references that use the qualified name syntax can refer to these elements using the index. In SmallJava, only classes can be referred with qualified names.
The index is also used by Xtext to keep track of dependencies among files and to determine when to rebuild other files when a file changes.
Therefore, it makes no sense to index those elements that cannot be referred from other files. In our DSL, this means that it does not make sense to index variables, since they can only be accessed from a method in the containing class. Instead, we leave the methods and their parameters in the index, because we want the other files using a method of an external class to be notified if the method changes name or parameters. Although the presence...
