On Tue, Oct 06, 2026 at 08:12:46PM +0100, Gavin Smith wrote:
> On Sun, Oct 04, 2026 at 03:24:54PM +0200, Patrice Dumas wrote:
> > If we want to go in that direction, we would need to change the
> > specification of the Texinfo language, as explained in the "Multiple
> > Spaces" Texinfo manual node, which is (from the Info reader):
> >
> > Occasionally, you may want to produce several consecutive spaces,
> > either for purposes of example (e.g., what your program does with
> > multiple spaces as input), or merely for purposes of appearance in
> > headings or lists. Texinfo supports three commands: ‘@SPACE’, ‘@TAB’,
> > and ‘@NL’, all of which insert a single space into the output. (Here,
> > ‘@SPACE’ represents an ‘@’ character followed by a space, i.e., ‘@ ’,
> > ‘TAB’ represents an actual tab character, and ‘@NL’ represents an ‘@’
> > character and end-of-line, i.e., when ‘@’ is the last character on a
> > line.)
> >
> > I think that this matches well the texi2any behaviour, but not the TeX
> > behaviour, therefore we need to change this specification before
> > changing texi2any.
>
> I am working on adding a note about this to the manual, but I need to
> investigate this further as it seems that simply "A@ B" does not
> produce the same output with texi2any as with texinfo.tex. texi2any
> for Info output produces "A B" which is expected, with two spaces, but
> texinfo.tex appears to only produce a single space.
Mystery solved - TeX skips spaces after a "control space". Here's how
"TeX by Topic" explains it:
State S is entered in any mode after a control word or control space
(but after no other control symbol), or, when in state M, after a
space. In this state all subsequent spaces or end-of-line characters
in this input line are discarded.
I've added text to the manual following your suggestion:
For consistent output regardless of whether ‘texi2any’ or TeX is
processing your Texinfo file, you should always follow a ‘@SPACE’ or
‘@TAB’ command with a non-whitespace character on the same line. The
reason for this is that TeX ignores space characters following ‘@SPACE’,
and also strips trailing whitespace from input lines, so treats ‘@SPACE’
at the end of a line as if the ‘@NL’ command had appeared instead.
One workaround to use ‘@SPACE’ at the end of a line is to add an
empty ‘@w{}’ after the command. For example:
A@ @w{}
B.
This produces:
A B.
--with two spaces between ‘A’ and ‘B’, one resulting from the ‘@ ’, and
the second resulting from the end-of-line.
