Re: @math{-} does not produce a minus sign in Info

[Gavin Smith]

On Tue, Oct 25, 2022 at 01:25:35PM +0200, Vincent Lefevre wrote:
> If I write @math{-2} (where "-" is the ASCII HYPHEN-MINUS character),
> I do not get a minus sign in Info, contrary to @minus{}2, while the
> Texinfo manual suggests the use of @math with the regular '-' character
> instead of @minus:
> 
> 11.8.9 '@minus' (-): Inserting a Minus Sign
> -------------------------------------------
> [...]
>    If you actually want to typeset some math that does a subtraction, it
> is better to use '@math'.  Then the regular '-' character produces a
> minus sign, as in '@math{a-b}' (*note Inserting Math::).

Why does it matter if the Unicode minus character is not used in Info?
The ASCII hyphen is just as good.  It's wrong to say that - isn't a minus
sign because it looks just like one.

> 
> BTW, it contradicts
> 
>   11.7 '@math' and '@displaymath': Formatting Mathematics
> 
> which says that "the '@math' command has no special effect on the Info
> output".

The @minus node wasn't specifically discussing Info output.  We can change
it to

diff --git a/doc/texinfo.texi b/doc/texinfo.texi
index bc1eebac87..1b7f029ba4 100644
--- a/doc/texinfo.texi
+++ b/doc/texinfo.texi
@@ -10308,8 +10308,7 @@ @node @code{@@minus}
 @end display
 
 If you actually want to typeset some math that does a subtraction, it
-is better to use @code{@@math}.  Then the regular @samp{-} character
-produces a minus sign, as in @code{@@math@{a-b@}} (@pxref{Inserting
+is better to use @code{@@math}, as in @code{@@math@{a-b@}} (@pxref{Inserting
 Math}).
 
to eliminate discussion of what character - may be output as.

> So I suppose that either @math{-} should generate a minus sign in Info
> (and HTML) output or the manual should suggest the use of both @math
> and @minus: @math{a@minus{}b}.

Neither of these are a good idea.  As it's been stated many times before,
no interpretation of the argument takes place for @math in Info, and
@math{a@minus{}b} is clearly worse than @math{a-b} so we are not going
to recommend that usage to people.

If we needed to have consistency between @math{-} and @minus{} in Info
output, the only way to achieve this would be to make @minus{} output
an ASCII hyphen.  This wouldn't do anything for HTML output, though.