On Wed, Nov 09, 2022 at 12:47:38PM +0100, Patrice Dumas wrote:
> I am not sure that this can be easily fixed, there are lots of caveats
> put forward in the manual because macros in TeX is an area where things
> seems to be difficult to get right, but I agree that this is an issue as
> I can't see what in the macro definition would trigger an extra space
> (and the equivalent using texi2any macros would not have that space,
> though it is may not be relevant to the issue). If it cannot be fixed,
> maybe it could be documented?
I've added the following to the manual:
• Expanding macros in a math context may lead to poor spacing in TeX
output. For example:
@iftex
@macro atan
\\mathop{\\rm atan}
@end macro
@end iftex
@math{@atan{}(x)}
The braces following ‘@atan’ are treated by TeX as a subformula,
leading to extra space before the opening parenthesis. You can
work around this by defining a raw TeX macro instead:
@tex
\gdef\atan#1{\mathop{\rm atan}}
@end tex
The ‘#1’ in this definition absorbs the braces, so that the spacing
is as expected for the ‘\mathop’ object.
