Re: PL/pgSQL RENAME bug?

Bruce Momjian wrote:

Digging into it now, I remember why it is there. In the
Oracle world, someone can declare a trigger that references
to NEW or OLD by other names. This RENAME was a workaround so
one doesn't need to change the whole trigger body, but just
adds a line in the DECLARE section doing the job.

Therefore, I think removal is not such a good idea. Fixing it
properly will take a little longer as I am a little busy at
the moment.

Jan

> Jan, seems no one has commented on this. Patch?
>
> Jan Wieck wrote:
> > Tom Lane wrote:
> > > "Command Prompt, Inc." <pgsql-hackers(at)commandprompt(dot)com> writes:
> > > > Mainly, the existing documentation on the RENAME statement seems
> > > > inaccurate; it states that you can re-name variables, records, or
> > > > rowtypes. However, in practice, our tests show that attempting to RENAME
> > > > valid variables with:
> > > > RENAME varname TO newname;
> > > > ...yeilds a PL/pgSQL parse error, inexplicably. If I try the same syntax
> > > > on a non-declared variable, it actually says "there is no variable" with
> > > > that name in the current block, so...I think something odd is happening. :)
> > >
> > > Yup, this is a bug. The plpgsql grammar expects varname to be a T_WORD,
> > > but in fact the scanner will only return T_WORD for a name that is not
> > > any known variable name. Thus RENAME cannot possibly work, and probably
> > > never has worked.
> > >
> > > Looks like it should accept T_VARIABLE, T_RECORD, T_ROW (at least).
> > > T_WORD ought to draw "no such variable". Jan, I think this is your turf...
> >
> > Sounds pretty much like that. Will take a look.
> >
> > >
> > > > The RENAME statement seems kind of odd, since it seems that you could just
> > > > as easily declare a general variable with the right name to begin with,
> > >
> > > It seems pretty useless to me too. Perhaps it's there because Oracle
> > > has one?
> >
> > And I don't even remember why I've put it in. Maybe because
> > it's an Oracle thing. This would be a cool fix, removing the
> > damned thing completely. I like that solution :-)
> >
> > Anyone against removal?
> >
> >
> > Jan
> >
> > --
> >
> > #======================================================================#
> > # It's easier to get forgiveness for being wrong than for being right. #
> > # Let's break this rule - forgive me. #
> > #================================================== JanWieck(at)Yahoo(dot)com #
> >
> >
> >
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> --
> Bruce Momjian | http://candle.pha.pa.us
> pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
> + If your life is a hard drive, | 830 Blythe Avenue
> + Christ can be your backup. | Drexel Hill, Pennsylvania 19026
>

--

#======================================================================#
# It's easier to get forgiveness for being wrong than for being right. #
# Let's break this rule - forgive me. #
#================================================== JanWieck(at)Yahoo(dot)com #

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Added to TODO:

o Fix PL/pgSQL RENAME to work on on variable names

---------------------------------------------------------------------------

Jan Wieck wrote:
> Bruce Momjian wrote:
>
> Digging into it now, I remember why it is there. In the
> Oracle world, someone can declare a trigger that references
> to NEW or OLD by other names. This RENAME was a workaround so
> one doesn't need to change the whole trigger body, but just
> adds a line in the DECLARE section doing the job.
>
> Therefore, I think removal is not such a good idea. Fixing it
> properly will take a little longer as I am a little busy at
> the moment.
>
>
> Jan
>
> > Jan, seems no one has commented on this. Patch?
> >
> > Jan Wieck wrote:
> > > Tom Lane wrote:
> > > > "Command Prompt, Inc." <pgsql-hackers(at)commandprompt(dot)com> writes:
> > > > > Mainly, the existing documentation on the RENAME statement seems
> > > > > inaccurate; it states that you can re-name variables, records, or
> > > > > rowtypes. However, in practice, our tests show that attempting to RENAME
> > > > > valid variables with:
> > > > > RENAME varname TO newname;
> > > > > ...yeilds a PL/pgSQL parse error, inexplicably. If I try the same syntax
> > > > > on a non-declared variable, it actually says "there is no variable" with
> > > > > that name in the current block, so...I think something odd is happening. :)
> > > >
> > > > Yup, this is a bug. The plpgsql grammar expects varname to be a T_WORD,
> > > > but in fact the scanner will only return T_WORD for a name that is not
> > > > any known variable name. Thus RENAME cannot possibly work, and probably
> > > > never has worked.
> > > >
> > > > Looks like it should accept T_VARIABLE, T_RECORD, T_ROW (at least).
> > > > T_WORD ought to draw "no such variable". Jan, I think this is your turf...
> > >
> > > Sounds pretty much like that. Will take a look.
> > >
> > > >
> > > > > The RENAME statement seems kind of odd, since it seems that you could just
> > > > > as easily declare a general variable with the right name to begin with,
> > > >
> > > > It seems pretty useless to me too. Perhaps it's there because Oracle
> > > > has one?
> > >
> > > And I don't even remember why I've put it in. Maybe because
> > > it's an Oracle thing. This would be a cool fix, removing the
> > > damned thing completely. I like that solution :-)
> > >
> > > Anyone against removal?
> > >
> > >
> > > Jan
> > >
> > > --
> > >
> > > #======================================================================#
> > > # It's easier to get forgiveness for being wrong than for being right. #
> > > # Let's break this rule - forgive me. #
> > > #================================================== JanWieck(at)Yahoo(dot)com #
> > >
> > >
> > >
> > > _________________________________________________________
> > > Do You Yahoo!?
> > > Get your free @yahoo.com address at http://mail.yahoo.com
> > >
> > >
> > > ---------------------------(end of broadcast)---------------------------
> > > TIP 5: Have you checked our extensive FAQ?
> > >
> > > http://www.postgresql.org/users-lounge/docs/faq.html
> > >
> >
> > --
> > Bruce Momjian | http://candle.pha.pa.us
> > pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
> > + If your life is a hard drive, | 830 Blythe Avenue
> > + Christ can be your backup. | Drexel Hill, Pennsylvania 19026
> >
>
>
> --
>
> #======================================================================#
> # It's easier to get forgiveness for being wrong than for being right. #
> # Let's break this rule - forgive me. #
> #================================================== JanWieck(at)Yahoo(dot)com #
>
>
>
> _________________________________________________________
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> Get your free @yahoo.com address at http://mail.yahoo.com
>
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--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026