[Test] Add a grammar for string tree.
[Attribute] Add type_name attribute.
[MissingFile] AST of the attributed grammar.
[Typing] AST of the typed grammar.
[Typing] Typed expressions using anonymous structures.
[Typing] Type the choice statement with an enum.
[Typing] Type the named sequence expression and type alias on the others.
[Typing] Add a type visitor and a check for inline loop.
[Typing] Move the inlining into a dedicated file.
[Typing] Parametrize expression by expression node so it can be used in front and middle ends. Use Rc for storing rule type.