[latexrefman] \kern & \footnotesep

[Vincent Belaïche]

Then in the code provided in (info "(latex2e) \\footnote"), the
\footnoterule works properly only because \footnoterule is expanded in
vertical mode.

Also, the comment « % Kerns avoid vertical space » could certainly be
improved by replacing « Kerns » by « \kern », as TeXByTopic §4.3.2
states :

« The \kern command has (almost) nothing to do with the phenomenon of
kerning; it is explained in Chapter 8.»

Would this rewording improve the manual :

@example
% \footnoterule is expanded in vertical mode, thus \kern commands
% ensure that no vertical space is created, and the rule is separated
% vertically 2pt above the note text
\renewcommand*@{\footnoterule@}@{%
  \kern -3pt                         % This -3 is negative
  \hrule width \textwidth height 1pt % of the sum of this 1
  \kern 2pt@}                         % and this 2
@end example

   V.

Le sam. 10 sept. 2022 à 22:42, Karl Berry <karl at freefriends.org> a écrit :
>
>     My understanding of the TeX \kern command is that it controls the
>     inter-letter *horizontal* space (see for instance
>
> Regardless of what's on a random web page, \kern inserts vertical
> space in vertical mode, and horizontal space in horizontal mode(s).
> texbook.tex (ch.13):
>   ... For example, ^|\kern| specifies vertical spacing in vertical mode,
>
> karl