Scoping with Xtext / TMF

The new Xtext version in Galileo changed a few things. To do scoping, a little bit of Java development is necessary. Documentation is very brief, but with a little research it is quite easy. Consider the following grammar, that allows us to define components, instances of those components and – the interesting part here – connect ports of instances:

The default code completion will traverse all defined Ports for the references p and p2 in the Connection rule. A better behaviour would be:

  • Show only the ports in the instances (in, in2)
  • For p, show only “OUT”-Ports, for p2, show only “IN”-ports.

To do this, we need to define methods in a class derived from AbstractDeclarativeScopeProvider. The method names follow the signature scope_<rule>_<element>, so the code fragment for p2 is:

With some additional code the full Provider for p and p2 looks like this:

4 thoughts on “Scoping with Xtext / TMF

  1. Hello,

    Please, can you post the whole Xtext-grammar?
    It is not possible to write a “Instance” or “Connection”-rule in the created editor. And what do you mean with the rule “Interface”?


    Thomas V.

  2. The grammar is only an excerpt to show the scoping. I might publish more of it when I have time.

  3. Scoping is not very well documented. Could you please provide an example for the new Xtext 1.0

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