Noob here. I'm getting started on building a Postgres extension.
I'd like to add some keywords/clauses to the SELECT statement. For my
particular application, the syntax with new keywords would be way better
than trying to do it through functions alone. I would add some new keywords
followed by expressions similar to those allowed in WHERE and GROUP BY
clauses. The new SELECT would return multiple result sets.
I did find an example where someone did modify the parser:
http://www.neilconway.org/talks/hacking/hack_slides.pdf
Question: is it possible to do this in an extension? Or do I have to fork
the Postgres codebase itself?
Obviously, I'd prefer the former. Forks are bad.