Re: Split-up ECPG patches

Michael Meskes írta:
> On Sat, Aug 08, 2009 at 05:48:57PM +0200, Boszormenyi Zoltan wrote:
>
>> ...
>> "/usr/bin/perl" ./parse.pl . < ../../../../src/backend/parser/gram.y >
>> preproc.y
>> /usr/bin/bison -d -o preproc.c preproc.y
>> preproc.y: conflicts: 2 shift/reduce
>> preproc.y: expected 0 shift/reduce conflicts
>> make[4]: *** [preproc.c] Error 1
>> make[4]: Leaving directory
>> `/home/zozo/Schönig-számlák/leoni/2/pgsql/src/interfaces/ecpg/preproc'
>> ...
>>
>
> Right, I missed this one. But it's ecpg specific and should not be fixed by
> changing gram.y.

Debatable. :-)

> The problem is that SignedIconst might be a char variable,
> too. So how shall the parser know whether str in "FETCH BACKWARD :str" carries
> the number of records to move backwards ot the cursor name.

This was the problem, yes.

> A possible solution
> would be to force a numeric variable for numeric data.

By which you would remove a feature.
With the proposed core grammar change,
the feature where you can pass the number of
records to be fetched in a string variable
can be kept.

> Also keep in mind that a
> fetch statement without from/in is an addition on top of the standard.

It seems to be Informix-specific, I just looked it up in
their guide_to_sql_syntax.pdf.

> I'm not
> sure if any other dbms still allows this construct, so we might we well remove
> it for 8.5. Or move it to a special compatibility mode.
>

How would you do that? With a completely
different parser for Informix-compatibility?
It would reduce maintainability. Or does bison
allow conditionally enabled rules somehow?
It sure would come in handy in this case.

Best regards,
Zoltán Böszörményi

--
Bible has answers for everything. Proof:
"But let your communication be, Yea, yea; Nay, nay: for whatsoever is more
than these cometh of evil." (Matthew 5:37) - basics of digital technology.
"May your kingdom come" - superficial description of plate tectonics

----------------------------------
Zoltán Böszörményi
Cybertec Schönig & Schönig GmbH
http://www.postgresql.at/