@vskip ...

[Jean-Christophe Helary]

So, I'm going through the texinfo manual, creating my own document step by step 
now to understand how that works.

Regarding @vskip, it seems to be described only in the context of the copyright 
page, with little more explanations:

==================>
To push the copyright notice and the other text on the copyright page towards 
the bottom of the page, use the following incantation after @page:
     @vskip 0pt plus 1filll

The @vskip command inserts whitespace in the TEX output; it is ignored in all 
other output formats. The ‘0pt plus 1filll’ means to put in zero points of 
mandatory whitespace, and as much optional whitespace as needed to push the 
following text to the bottom of the page. Note the use of three ‘l’s in the 
word ‘filll’; this is correct.
<=================>
@vskip amount
In a printed manual, insert whitespace so as to push text on the remainder of 
the page towards the bottom of the page. Used in formatting the page with the 
argument ‘0pt plus 1filll’. (Note spelling of ‘filll’.) @vskip may be used only 
in contexts ignored for Info. See Section 3.4.4 [Copyright], page 22.
<==================

And that's pretty much it. (I just realized thanks to the monospace font of 
this mail that it is not Opt, but 0pt)

Now, when I check Knuth's TeXBook for "filll", I find it in Chapter 12 (Glue):

==================>
For example, \vfil, \vfill, \vss, and \vfilneg are essentially equivalent
to the glue specifications

\vskip 0pt plus 1fil
\vskip 0pt plus 1fill
\vskip 0pt plus 1fil minus 1fil
\vskip 0pt plus -1fil

respectively. It’s usually best to stick to the first order infinity (fil) as 
much as you can, resorting to second order (fill) only when you really need 
something extremely infinite. Then the ultimate order (filll) is always 
available as a last resort in emergencies. (TEX does not provide a ‘\vfilll’ 
primitive, since the use of this highest infinity is not encouraged.)
<==================

1) Knuth does not encourage the use of filll (I don't pretend to understand 
why), why does Texinfo has use only for filll and not for the 2 others ?

2) Texinfo seems to use filll exclusively in the context of the copyright page, 
so why not create a Texinfo "primitive" that would hide the complexity of the 
"incantation", something like @vfilll ?

I was thinking something like this would work:

@deffn Command vfilll
vskip Opt plus 1filll
@end deffn

but I keep gettin error messages that I don't understand so I'll try again when 
I have a better understanding of how definitions work.

3) Is it OK to add a reference to that part of the TeXbook in the Texinfo 
manual so that users understand why this thing exists ?


Jean-Christophe Helary
-----------------------------------------------
http://mac4translators.blogspot.com @brandelune