Re: [Groff] RE: Small bug in groff 1.19.2 footnote number contro

[Keith Marshall]

On Mon, 2007-09-17 at 17:33 +0200, Werner LEMBERG wrote:
> > So I ask the question of the group:
> > 
> >       Do we want to implement "backward compatibility" of
> >     undocumented things like the number register  :p  in
> >     the groff package?
> > 
> > I vote no.

As do I.

> Hmm.  What to do in situations where the `inofficial' way was the only
> choice?

Exactly as you would in any other situation, where you found it
necessary to exploit an undocumented feature; go ahead anyway, but
prominently include a comment in the document, to the effect that:

  .\" This document makes gratuitous use of the undocumented `:p'
  .\" register, defined by the XYZ implementation of `mm'; it may
  .\" not be readily portable to other troff implementations.
  .
  .\" The equivalent, but also undocumented, feature in groff `mm'
  .\" is controlled by the `ft*nr' register; thus
  .
  .   aln :p ft*nr
  .
  .\" should suffice, to allow groff to emulate this undocumented
  .\" register usage.

Note that it's the `aln' request which is required here, and not `als'
as suggested in a previous post.

> I assume there wasn't any other, `official' possibility to reset the
> footnote counter, right?

Apparently not, but ...

> It's a genuine troff mm-ism.  E.g. we found out about it from the book
> by Narain Gehani (of AT&T) "Document Formatting and Typesetting on the
> UNIX System", ISBN 0 -9615336-0-9 (highly recommended, BTW).

This may establish `prior art', but it doesn't constitute official
documentation; there is no onus on groff, to replicate this undocumented
feature of another troff implementation, and I agree with Mike -- it
shouldn't do so.

Regards,
Keith.

BTW, without intending any offence to our German speaking colleagues,
there is no such word as `inofficial' in the English language.  Several
of you have used it recently; the word you intended is `unofficial'.