Re: Re: [PATCHES] Select parser at runtime

Ian Lance Taylor wrote:
> Along these lines, I don't think Bruce's suggestion of modifications
> to the Postgres gram.y is a good idea, because it causes the Oracle
> parser to add an ongoing cost to the Postgres parser.

Bruce, Tom and I discussed these issues during our time in
San Diego last month.

If we want to have both parsers available at runtime we need
to replace the YY (case-insensitive) prefix in the generated
files per parser and call the right one from tcop. Now for
some flex/bison combo's at least the prefix switches (to have
something different than YY) don't work reliable. There will
be some global YY-objects left, causing linkage problems.
That's why PL/pgSQL's scanner/parser's C-code is run through
sed(1).

If Bruce's suggestion of having both parsers in one source
with #ifdef, #else, #endif is better than separate sources
depends mainly on how big the differences finally will be.
Doesn't really bother me. Maybe we could start with a
combined one and separate later if it turns out that they
drift apart too much?

Jan

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