Re: BUG #6165: documentation bug in plpgsql-declarations.html and plpgsql-statements.html (or plpgsql parser bug)

On Mon, Aug 22, 2011 at 04:17:04PM -0400, Tom Lane wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
> > On Wed, Aug 17, 2011 at 1:21 AM, raf <raf@raf.org> wrote:
> >> so, there is either a plpgsql parser bug that treats the sql equality
> >> operator as the plpgsql assignment operator, or "=" is an undocumented
> >> alternative to the documented plpgsql assignment operator (":=").
>
> > I think it's the latter.
>
> It's definitely intentional, not a bug, so far as the source code is
> concerned:
>
> assign_operator : '='
>                 | COLON_EQUALS
>                 ;
>
> > I have a vague recollection that we might
> > have left that undocumented on purpose, but I'm not actually sure why
> > we support it in the first place.
>
> I think it's legacy at this point.  We have discussed before whether to
> document it, and IIRC the general feeling was "if we do document it,
> we'll never be able to get rid of it".  Whether we could get rid of it
> now (instead of documenting it) was not seriously discussed.  I've seen
> at least a few people saying that they do rely on it ...

I think the question is whether '=' is used enough that we have to
mention that it is a non-standard extension that might be removed
someday, or something.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +