[XeTeX] additional beginL endL nodes in math

[David Carlisle]

On 16 April 2015 at 11:54, Vafa Khalighi <glkvafa at gmail.com> wrote:
> I have not got TeXLive 2015 but that is just bad. Does the new xetex effect
> any other of math typesetting that used to work fine with Knuth TeX?

yes see the example I posted in the second message I posted to this thread
in Knuth TeX it typesets 700 in xetex 2015 it typesets 0, That was
engineered to typeset a test value, but real documents that produce
different spacing
are inevitable, as this later breqn example shows.

>  does it
> break any package? with breqn the issue is not too bad since breqn is an
> experimental package and not a lot of people are aware of it or use it. I am
> not saying that it is ok but that if it does not break any other packages,
> then it is not too bad.
>

It's hard to know what which packages or documents will change. tex-xet makes
math expressions opaque to tests with \lastskip, \unskip and friends as the
extra non-removable \endR node that is inserted stops the expression
being dis-assembled.

As I said in the initial message in this thread that breaks 77 of our
test files and
affects any document that is dissembling horizontal lists constructed from math.
It was easy to guess breqn was doing that kind of thing so I made a
small example
and as expected it failed in 2015. Other packages, who knows....


David