Given a LGPL'ed grammar file, is the source generated by a compiler-compiler for the grammar a derivative works? What about if the grammar file was modified before it was given as input to the compiler-compiler? There isn't any linking, at least not in the conventional sense.
If the output is a derivitive work, must I then simply provide the (modified) grammer sources making any best efforts to ensure the grammar will function without dependencies imposed by the program/library using it? Or are there more restrictions which must be resolved?