Re: Adding xreflable

On Thu, Jun  4, 2020 at 07:11:41PM +0200, Peter Eisentraut wrote:
> On 2020-06-04 00:38, Alvaro Herrera wrote:
> > On 2020-Jun-02, Bruce Momjian wrote:
> > 
> > > I can adjust things, but what logic are we following?  Before my patch,
> > > sepgsql had an xreflabel, and vacuumlo did not.  I would like to have a
> > > documented policy of where we should have xreflabels, and where not, and
> > > I can then adjust things to match.  I don't mind using <link> but it is
> > > confusing to be able to reference xreflabels in some places and be
> > > required to use link in others.
> > 
> > I think a possible rationale would be to *not* include xreflabel for
> > elements that get numbered (so references become, e.g., "see Section 32.5"),
> > and include them for those that don't -- so that they can be referenced
> > at all.
> 
> Yes, basically everything that already has a generated label doesn't need an
> xreflabel.
> 
> Also, if you apply xreflabels somewhere, it needs to be done consistently
> across all siblings, so you don't get a different style of text depending on
> which section you happen to link to.
> 
> And moreover, there should be some general utility for the xreflabel, not
> just the linking needs of one particular source location.
> 
> The xreflabels used for the GUC variables are good examples of all three of
> those points.
> 
> Generally, xreflabels are a bit of antipattern IMO, so there need to be
> solid arguments in favor of adding more.

OK, I have reverted the patches that added xreflabels and added this
text to the bottom of README.links:

- xreflabels added to tags prevent the chapter/section for id's from being
  referenced;  only the xreflabel is accessible.  Therefore, use xreflabels
  only when linking is common, and chapter/section information is unneeded.

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

  The usefulness of a cup is in its emptiness, Bruce Lee