On Fri, Jun 23, 2023 at 01:38:23PM +0200, Hans Hagen via ntg-context wrote:
> On 6/23/2023 12:43 PM, Carlos via ntg-context wrote:
> > On Thu, Jun 22, 2023 at 03:32:25PM +0200, Hans van der Meer via ntg-context
> > wrote:
> > > \starttext
> > > x \rightarrowfill x
> > >
> > > x \leftarrowfill x
> > >
> > > hbox to 5cm:
> > >
> > > y\hbox to5cm{\rightarrowfill}y
> > >
> > > y\hbox to5cm{\leftarrowfill}y
> > > \stoptext
> > >
> > > But obviously not in an dimensioned \hbox, whereas Knuth's version does
> > > that too.
> > >
> > >
> > >
> > > > On 22 Jun 2023, at 15:11, Hans Hagen via ntg-context
> > > > <[email protected]> wrote:
> > > >
> > > > x \rightarrowfill x
> > > >
> > > > x \leftarrowfill x
> > >
> > > yours sincerely
> > > dr. Hans van der Meer
> > >
> > > 
> >
> > I find this interesting. I agree with Hans vdM.
> >
> > So what would be the acceptable standard given an x length of a glue?
> >
> > In the above examples, it's all preset.
> >
> > Is a rule of thumb — no pun intended here — to apply thereafter
> > a glue, in this case a \vrule that follows the box and precedes the
> > other glue? that is, the \rightarrowfill or \leftarrowfill?
> >
> > I mean. Once you get the glues messed up, the whole box crumbles.
>
> I'm not sure how you can mess up glue so that the box is no longer a box.
> Boxes remain boxes.
I guess that's the same mentality behind a fixed glue in LMTX, while
trying not to mess up the box. Back to point A and the main reason of the
op's question.
Then again, the only way to resemble what TeX does is by re/defining
and copied verbatim from The TeXbook both rightarrowfill and
leftarrowfill
and unlike with TeX in which an
\hbox to 1in{\vrule \rightarrowfill \ 1cm \leftarrowfill\vrule}
it says 1cm but it'd be more than that, and accurately so
>
> > How good would \meaning be here, notwithstanding the valuable info of
> > the macro it provides, if it can't print out, let alone source it up,
> > the more accurate dimension, let alone the measurement.
>
> I don't follow. Does this come from ChapGPT?
>
That's funny.
But as chatgpt says:
"Sorry about that. \meaning\rightarrowfill is
\begingroup \scratchunicode 8594\relax \adaptivebox [mathfiller][alterna
tive=8594]{\hss \strut \hss }\endgroup "
That's what lmtx returned after Hans vdM sample
> > So, one would need to know the preset layout of the page to have an idea
> > about it?
> >
> > Hans H. pulled the old modified trick of 'works here'.
>
> Well, when used in a paragraph it works indeed. No trick involved. But as it
> uses a specific mechanism in an hbox you need to trigger that (unless you
> want to add overhead that will kake tex crawl).
>
> > Like a magician… now all of a sudden evetything works, but unlike TeX's
>
> Not sure what this refers to. Much of TeX is magick but what is bad about
> that?
>
> > \hbox to 1in{\vrule \rightarrowfill \ 1in \leftarrowfill\vrule}
> >
> > or
> >
> > \hbox to 1cm{\vrule \rightarrowfill \ 1cm \leftarrowfill\vrule}
> >
> > which gives an accurate description, not to mention measurement,
>
> It depends on what you expect. First of all, your assumption that the arrow
> fill is the same as in plain tex is wrong.
Why would it be wrong?
When I type
\hbox to 3cm{\rightarrowfill} without a vrule
that's what I would normally expect
>
> (1) one can define an arrow fill using a leader that uses some (happen to be
> present in tex math fonts) glyphs: repeated minuses followed by some magic
> kern and an arrow head.
>
Can you apply it to pagination without breaking?
Highly doubt it.
> (2) You can hope that the magick kern is right and that the minus aligns
> with the arrows bar.
>
> (3) You also assume that the math font matches the text font.
>
> (4) Normally an arrow fill is something math anyway. Where there can also be
> something on top or below, or where it can be a top or bottom accent.
>
> > a
> >
> > \vbox to 5pt{x\vrule\rightarrowfill \ x \leftarrowfill\vrule\ x}
> >
> > or
> >
> > x \rightarrowfill x
> > x \leftarrowfill x
> >
> > or
> >
> > \vbox to 3pt{x\vrule\rightarrowfill \ \leftarrowfill\vrule\ x}
> >
> > \ \rightarrowfill \
> > \ \leftarrowfill \
> >
> >
> > in LMTX doesn't say much
> What should it say? You get a space, an arrow and a discarded space.
>
> That said: I think you miss a few points here:
>
> (1) I know Hans vd Meer well and he knows ConTeXt well. He's quite capable
> of figuring out how to use advanced features and I bet he likes the
> following variant of arrows in text. Next time we meet I'll show him some
> more adaptive tricks (although I bet he can figure them out himself).
>
> \starttext
>
> % \setupexternalfigures
> % [location={default,global}]
>
> % \startsetups adaptive:test
> % \setbox\usedadaptivebox\hbox to \usedadaptivewidth yoffset
> -\usedadaptivedepth \bgroup
> % \externalfigure
> % [cow.pdf]
> % [width=\usedadaptivewidth,
> % height=\dimexpr\usedadaptiveheight+\usedadaptivedepth\relax]%
> % \egroup
> % \stopsetups
>
> \startsetups adaptive:test
> \setbox\usedadaptivebox\hbox to \usedadaptivewidth yoffset .25ex \bgroup
> \startMPcode
> drawarrow ((0,0) -- (\the\usedadaptivewidth,0)) randomized
> (ExHeight/2);
> \stopMPcode
> \egroup
> \stopsetups
>
> \dorecurse{5}{
> \dostepwiserecurse{1}{150}{1}{%
> this~#1.##1 is~#1.##1 test~#1.##1
> {\adaptivebox[strut=yes,setups=adaptive:test]{\strut}}
> }
> \blank
> }
>
> \stoptext
>
> (2) If someone wants a plain (or fot that matter latex) solution then one
> can use these macro packages or write a macro that mimicks expectations.
>
> (3) I don't like "Hans H. pulled the old modified trick of 'works here'."
> kind of remarks because they have a rather negative undertone and I don't
> know how to read that.
>
No. I didn't mean anything by it. Just that I disagree with the
implementation. Again, I expect what TeX returns rather than what LMTX
returns.
No need to re-invent the wheel. (if there's undertone in that so be it)
And of course it's working! Everything works, right? And that's exactly what
I meant.
>
> Hans
>
> -----------------------------------------------------------------
> Hans Hagen | PRAGMA ADE
> Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
> tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
> -----------------------------------------------------------------
>
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