Re: incorrect @math spacing for PDF output with an empty macro

[Vincent Lefevre]

On 2022-10-14 21:42:27 +0100, Gavin Smith wrote:
> On Fri, Oct 14, 2022 at 01:15:03PM +0200, Vincent Lefevre wrote:
> > FYI, the goal is to have @ttie{} equivalent to @tie{} except for
> > PDF output (where @tie{} also gives incorrect spacing).
> 
> I see.  As ever, using Texinfo commands inside @math is not advisable.

Here, @ttie{} is a macro that doesn't contain any Texinfo command.

> Even defining ttie as a simple \gdef had the same spacing problem.
> 
> It appears you are are right abut TeX treating the minus sign as a binary
> operator.  You can format it correctly using \mathord:
> 
> @deftypefun int f3 ()
> @math{@var{n}@ttie{}=@ttie{}\mathord-2}
> @end deftypefun

This doesn't solve the issue, where the goal is to write the
same text for Info, HTML and PDF. That's precisely why I needed
the @ttie{} macro, whose expansion depends on the output type.

> In your use case, you can avoid line breaks using the @w command:
> 
> @deftypefun int f4 ()
> @w{@math{@var{n} = -2}}.
> @end deftypefun

If the @w ignored in math mode?

The manual just says:

   The space from '@w{ }', as well as being non-breakable, also will not
stretch or shrink.  Sometimes that is what you want, for instance if
you're doing manual indenting.  However, usually you want a normal
interword space that does stretch and shrink (in the printed output);
for that, see the '@tie' command in the next section.

For PDF output, I want the spaces to be the usual ones that are
generated in math mode.

-- 
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)