Re: Differences in `ne` and `bp` line-breaking behavior

[onf]

On Mon Dec 2, 2024 at 5:54 AM CET, G. Branden Robinson wrote:
> At 2024-12-01T22:17:47-0600, Dave Kemper wrote:
> > On Sun, Dec 1, 2024 at 8:27 PM G. Branden Robinson
> > <g.branden.robinson@gmail.com> wrote:
> > > By contrast, your sample size for `ne` misuse is one--yourself.
> > > Formerly two, before I came to understand the request.
> > 
> > Well, I agree with onf's point that .ne's behavior defies user
> > expectation, so you can lump me in with that sample.
>
> Well, maybe mine too.  This one surprised me:
>
> $ printf 'Hello, world!\n.bp\n.c2 @\none two three\nfour five six\n@bp\nseven 
> eight nine\n.br\nten eleven twelve\n' | groff -a
> <beginning of page>
> Hello, world!
> <beginning of page>
> <beginning of page>
> one two three four five six seven eight nine
> ten eleven twelve
>
> I wasn't expecting TWO page breaks there.  But I've got 'em.  Is that
> wrong?  I'm not sure.

I was expecting them there. In fact, what I wasn't expecting when I
began using troff is for multiple .bp requests to be 'squeezed' into
one. This becomes really annoying when trying to pad the end of a
booklet with blank pages (which is necessary for imposition onto a
larger paper format), for instance. In fact, I thought that putting
some vertical space and \& after a .bp makes troff not squeeze the
following .bp, but I fail to bring this behavior about with nroff.
I am consoled by the discovery that 'bp apparently doesn't do that.

Does anyone know what's the rationale behind multiple .bp requests
being squeezed?

> > This is at best a tangential point: roff is used for plenty of things
> > besides man pages.
>
> Not at best tangential--man pages are the _predominant_ application of
> roff in publicly available documents.  That matters.

That doesn't necessarily mean groff should base its behavior on the
expectations of manpage writers, though.

> > I'd rather ask, does it make the language easier to grasp / more
> > intuitive without introducing incompatibilities that will break
> > historical usage?
>
> You state the criterion well, expressing the concerns we must balance.

So far our discussions have been more about the former, though.
You asserted that the current behavior is correct and my intuition
incorrect. You also asserted I am the only person who expects `ne`
to behave in this way.

~ onf