This language defines arithmetical expressions (prefix notation) that can use constant values. Example:

val foo := 1
val bar := 2

+ 1 * bar bar

The grammar is here:

fr.insa.exp/src/fr/insa/exp/Exp.xtext

The validator that checks the arithmetical expression is correct is here:

fr.insa.exp/src/fr/insa/exp/validation/ExpValidator.java

The generator that writes in a file the result of the expression:

fr.insa.exp/src/fr/insa/exp/generator/ExpGenerator.xtend

The unit tests that test the grammar:

fr.insa.exp.tests/src/fr/insa/exp/tests/ExpParsingTest.xtend

The customised outline:

fr.insa.exp.ui/src/fr/insa/exp/ui/outline/ExpOutlineTreeProvider.java

The quick-fix features:

fr.insa.exp.ui/src/fr/insa/exp/ui/quickfix/ExpQuickfixProvider.java

The content assist features:

fr.insa.exp.ui/src/fr/insa/exp/ui/contentassist/ExpProposalProvider.java

Setting the keywords colour:

fr.insa.exp.ui/src/fr/insa/exp/ui/ExpUiModule.java

fr.insa.exp.ui/src/fr/insa/exp/ui/coloring/ExpHighlightingConfiguration.java (to create)

Semantic highlighting:

fr.insa.exp.ui/src/fr/insa/exp/ui/ExpUiModule.java

fr.insa.exp.ui/src/fr/insa/exp/ui/coloring/ExpSemanticHighlightingCalculator.java (to create)

fr.insa.exp.ui/src/fr/insa/exp/ui/coloring/ExpHighlightingConfiguration.java

Manual cross-reference (scoping):

fr.insa.exp/src/fr/insa/exp/scoping/ExpScopeProvider.java

EObject rootElement = EcoreUtil2.getRootContainer(myModelElement);

// Getting the root of the model
EObject rootElement = EcoreUtil2.getRootContainer(myModelElement);
// Getting all the instances of MyModelObjectType in the model
List<MyModelObjectType> objects = EcoreUtil2.getAllContentsOfType(rootElement, MyModelObjectType.class);

MyRule: 'mytoken';

In this example Xtext optimises the grammar: since MyRule contains tokens only (ie no rule access), it considers MyRule as a terminal (ie a lexer rule) and does not create a class MyRule.

To force the class creation, you have to write that:

MyRule: {MyRule} 'mytoken';

This precises the name of the class to instantiate (this class does not exist yet, it is Xtext that generates it in the src-gen folder).