def protected void generateFile(String fileName, CharSequence contents) {
    fsa.generateFile(fileName, contents);
}

Model:
	greetings+=Greeting*;
	
Greeting:
	'Hello' name=ID doNotGenerate?='skip'? '!';

class MyDslGenerator extends AbstractGenerator {

	override void doGenerate(Resource resource, IFileSystemAccess2 fsa, IGeneratorContext context) {
		for (g : resource.allContents.filter(Greeting).toIterable.filter[!isDoNotGenerate]) {
			fsa.generateFile(g.name+".txt",'''«g.name»''')
		}
	}
}