Here are some changes in the java grammar that I would like you to take a look at:
SourceFile
The ASTs in xml format start with the SourceFile tag. Even though it's not really part of the language's grammar, it would be useful to have it to match the xml's structure.
Mandatory/Optional
Some tags were wrongly marked as mandatory based on the jhotdraw ASTs. I updated the attributes to match (I was working on it when the mandatory attribute was still there but I switched to using optionals). Here's a non-exhaustive list of fixes and their reason (if some are missing and you're not convinced, I'll provide an example on request).
TryStatement
catchClauses not mandatory - PrintFileAction ID="234"
ArrayCreation
dimensions not mandatory - ToggleViewPropertyAction ID="856"
CompilationUnit
imports not mandatory - AbstractHarmonicRule ID="1"
Initializer
modifiers not mandatory - JColorWheel ID="3492"
InfixExpression
missing this, makes leftoperand not mandatory - AbstractDrawing ID="301"
missing this, makes rightoperand not mandatory - AbstractApplication ID="4820"
ConditionalExpression
missing this, makes thenExpression not mandatory - AbstractFigure ID="2005"
FieldDeclaration
modifiers not mandatory - GeneralPathTip ID="401
MethodDeclaration
modifiers not mandatory - DefaultDrawingViewTransferHandler ID="80"
ForStatement
updaters not mandatory - MDIApplication.java ID="712"
body not mandatory - TextAreaFigure ID="4542"
initializers not mandatory (because no EmptyExpression in AST) - BezierPath ID="6858"
TypeDeclaration
bodyDeclarations not mandatory - SelectAreaTracker ID="6
modifiers not mandatory - Polygon2D ID="15"
EnhancedForStatement
expression not mandatory (because 'this' missing in AST) - BezierPath ID="8416"
body not mandatory - similar to ForStatement
SuperConstructorInvocation
arguments not mandatory - PaletteTabbedPanelUI ID="290"
WhileStatement
body not mandatory - StreamPosTokenizer ID="1396"`
...
IExtendedModifier
I added <Annotation/> as a possible IExtendedModifier as explained here
Abstract tags
Some tags such as Operator appear in the ASTs as Strings (e.g. <operator>+</operator>). To respect the grammar, it should be <operator><PLUS_ASSIGN/></operator>. To solve this issue temporarily I added a image attribute to be able to map those strings to proper tags but, ideally, it should be generated as actual xml tags (unless there's a good reason why it isn't).
Other
Also, some other related remarks that are not part of the commit but I'd like your input on it:
NullLiteral
The NullLiteral tag should have one child token with a simplevalue of String. This is not the case in the ASTs were you find things like: <NullLiteral>null</NullLiteral> which doesn't respect the grammar. This should be changed in the ASTs generator (unless you already changed it in the meantime).
ThisExpression
I noticed the ThisExpression tag is missing in the ASTs. This has an impact on the grammar (optional/mandatory). Some examples are included in the list above. Is this normal? I know for example that EmptyStatement tags are excluded on purpose but not sure why ThisExpression would also be.
