Re: @displaymath in @iftex

[Gavin Smith]

On Wed, Aug 10, 2022 at 01:07:31PM -0700, Raymond Toy wrote:
> 
> I must be doing something wrong.  This is what I have:
> -------
> The following relationships are true:
> 
> 
> @ifhtml
> @displaymath
> \eqalign{
> m &= k^2 \cr
> k &= \sin\alpha
> }
> 
> @end displaymath
> @end ifhtml
> @ifinfo
> @math{m = k^2}
> 
> @math{k = sin(alpha)}
> 
> @end ifinfo
> @iftex
> @displaymath
> \eqalign{
> m &= k^2 \cr
> k &= \sin\alpha
> }
> 
> @end displaymath
> @end iftex
> 
> 
> Note that Abramowitz and Stegun uses the notation
> -----

If you put that into a Texinfo file and process it with texinfo.tex,
you get an error message like

! Missing $ inserted.
<inserted text> 
                $
<to be read again> 
                   @par 
l.24 


@par is a token that is inserted at the end of a paragraph, indicated
by blank lines.  l.24 refers to line 24, which was blank.  If you
remove that blank line, the file processes without error and the output
appears to be as expected:

> @iftex
> @displaymath
> \eqalign{
> m &= k^2 \cr
> k &= \sin\alpha
> }
> @end displaymath
> @end iftex