> Also, while it is possible to refer to named patterns of the parent
> grammar, it doesn't seem to be possible to refer to named patterns of
> other ancestors and I am wondering what's the reason for this.
The use case that motivates parentRef is that in section 13 of the tutorial.
I couldn't think of any use case where it would be necessary to refer to
ancestors other than the parent. It would be perfectly possible to
generalize parentRef, but in the absence of any use case to justify this, it
seemed better to avoid the additional complexity that such a generalization
would require.
James
