Re: Parser extensions (maybe for 10?)

On 12 April 2016 at 12:36, Arcadiy Ivanov <arcadiy(at)gmail(dot)com> wrote:

>
> Is there any interest and/or tips to allow a pluggable parser or at least
> allow some syntactical pluggability by extensions?
> I think this may allow some projects to move towards becoming an extension
> as opposed to forking the project entirely.
>

How would you go about it?

PostgreSQL uses a parser generator that produces C code as its output.
Extensions can't just patch the grammar and regenerate the parser. So even
if it were desirable, a fully extensible parser would require a total
rewrite of the parser/lexer.

That doesn't mean there can't be extension points for SQL syntax, they just
need to be planned carefully, located where they won't create parsing
ambiguities, and somewhat limited.

--
Craig Ringer http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services