Re: [XeTeX] xetex crash: interaction between interchar and linebreaklocale mechanisms

[Ulrike Fischer]

Am Wed, 6 Sep 2023 10:40:16 -0400 schrieb Andrew Goldstone:

> I believe this is the same issue as was raised on StackExchange in 2019
 
> https://tex.stackexchange.com/questions/503498/trouble-with-stacked-consonants-burmese-script
 
> but I couldn't find any further discussion of a fix for the crash.

I don't think that there is a fix and the xetex development is
rather stale. Personally I would try with lualatex.


-- 
Ulrike Fischer 
http://www.troubleshooting-tex.de/

Re: [XeTeX] xetex crash: interaction between interchar and linebreaklocale mechanisms

[Andrew Goldstone]

Thanks--it turns out that xelatex still segfaults if I attempt to combine
ucharclasses and \XeTeXinterwordspaceshaping=2 in a longer document. I do
think this is a bona fide xetex bug but don't have the knowledge of the
xetex source to trace it further.

As for lualatex it seemed to have more trouble than xelatex with the
complex ligatures in Burmese. The lineation issues are a lower priority for
my colleague than simply being able to typeset his mixed-script text, so
I'll help him to a workaround with xetex, if no other suggestions for fixes
are forthcoming.

All best,
Andrew

Sat, Sep 9, 2023 at 5:37 AM Ulrike Fischer  wrote:

> Am Wed, 6 Sep 2023 10:40:16 -0400 schrieb Andrew Goldstone:
>
> > I believe this is the same issue as was raised on StackExchange in 2019
>
> >
> https://tex.stackexchange.com/questions/503498/trouble-with-stacked-consonants-burmese-script
>
> > but I couldn't find any further discussion of a fix for the crash.
>
> I don't think that there is a fix and the xetex development is
> rather stale. Personally I would try with lualatex.
>
>
> --
> Ulrike Fischer
> http://www.troubleshooting-tex.de/
>
>

Re: [XeTeX] xetex crash: interaction between interchar and linebreaklocale mechanisms

[Mike Maxwell]

Back in 2018, I was trying to use LuaTeX to typeset multiple scripts. 
(We needed its capability to tell you where on the page bounding boxes 
were.)  LuaTeX worked ok for some scripts, but failed for example for 
Tamil, where glyphs don't always appear in the same order on the page as 
their underlying characters do.  This sort of issue arises with many 
Indic scripts, and something similar would probably happen with Burmese, 
which in some ways is an even more complex script than other Indic ones.


At the time, I recall the LuaTeX developers saying they were not 
interested in solving this issue, and that instead script-specific 
libraries should be developed.  (I'm going by memory here, I don't have 
links to that discussion, although see here: 
https://tex.stackexchange.com/questions/.)


Since that time, Khaled Hosny has conducted an "experiment" (his term) 
in using HarfBuzz in LuaTeX 
(https://tug.org/TUGboat/tb40-1/tb124hosny-harfbuzz.pdf, as reported in 
2019), and Kai Eigner also did similar work 
(https://github.com/tatzetwerk/luatex-harfbuzz).  The LuaTeX wikipedia 
page says LuaTeX "includes" the HarfBuzz engine (and links to the above 
two reports).


I haven't tried LuaTeX in recent years, but it sounds like if you ran 
Burmese through it and used the HarfBuzz shaper instead of the 
default(?) shaper, it might work for Burmese.


I'll be interested to hear what you find.

Mike Maxwell

On 9/9/2023 2:29 PM, Andrew Goldstone wrote:
Thanks--it turns out that xelatex still segfaults if I attempt to 
combine ucharclasses and \XeTeXinterwordspaceshaping=2 in a longer 
document. I do think this is a bona fide xetex bug but don't have the 
knowledge of the xetex source to trace it further.


As for lualatex it seemed to have more trouble than xelatex with the 
complex ligatures in Burmese. The lineation issues are a lower priority 
for my colleague than simply being able to typeset his mixed-script 
text, so I'll help him to a workaround with xetex, if no other 
suggestions for fixes are forthcoming.


All best,
Andrew

Sat, Sep 9, 2023 at 5:37 AM Ulrike Fischer > wrote:


Am Wed, 6 Sep 2023 10:40:16 -0400 schrieb Andrew Goldstone:

 > I believe this is the same issue as was raised on StackExchange
in 2019

 >

https://tex.stackexchange.com/questions/503498/trouble-with-stacked-consonants-burmese-script
 


 > but I couldn't find any further discussion of a fix for the crash.

I don't think that there is a fix and the xetex development is
rather stale. Personally I would try with lualatex.


-- 
Ulrike Fischer

http://www.troubleshooting-tex.de/ 

Re: [XeTeX] xetex crash: interaction between interchar and linebreaklocale mechanisms

[Ulrike Fischer]

Am Sat, 9 Sep 2023 15:39:51 -0400 schrieb Mike Maxwell:

> I haven't tried LuaTeX in recent years, but it sounds like if you ran 
> Burmese through it and used the HarfBuzz shaper instead of the 
> default(?) shaper, it might work for Burmese.

Yes that should work fine, luahbtex is the default engine for
lualatex since tl 2020 and harfbuzz can be used with latex +
fontspec by using the option Renderer=Harfbuzz

see e.g. https://tex.stackexchange.com/a/515934/2388

-- 
Ulrike Fischer 
http://www.troubleshooting-tex.de/

Re: [XeTeX] xetex crash: interaction between interchar and linebreaklocale mechanisms

[Mike Maxwell]

On 9/9/2023 4:20 PM, Ulrike Fischer wrote:

Am Sat, 9 Sep 2023 15:39:51 -0400 schrieb Mike Maxwell:


I haven't tried LuaTeX in recent years, but it sounds like if you ran
Burmese through it and used the HarfBuzz shaper instead of the
default(?) shaper, it might work for Burmese.


Yes that should work fine, luahbtex is the default engine for
lualatex since tl 2020 and harfbuzz can be used with latex +
fontspec by using the option Renderer=Harfbuzz

see e.g. https://tex.stackexchange.com/a/515934/2388


Thank you, that is good news!

At this point, what are the advantages of Xe(La)TeX vs. Lua(La)TeX? 
Apart from the crash Andrew reported, and the staleness of XeTeX's 
development.  Or maybe putting it differently, are there any situations 
that require XeTeX?


   Mike Maxwell

Re: [XeTeX] xetex crash: interaction between interchar and linebreaklocale mechanisms

[Zdenek Wagner]

so 9. 9. 2023 v 23:28 odesílatel Mike Maxwell  napsal:
>
> On 9/9/2023 4:20 PM, Ulrike Fischer wrote:
> > Am Sat, 9 Sep 2023 15:39:51 -0400 schrieb Mike Maxwell:
> >
> >> I haven't tried LuaTeX in recent years, but it sounds like if you ran
> >> Burmese through it and used the HarfBuzz shaper instead of the
> >> default(?) shaper, it might work for Burmese.
> >
> > Yes that should work fine, luahbtex is the default engine for
> > lualatex since tl 2020 and harfbuzz can be used with latex +
> > fontspec by using the option Renderer=Harfbuzz
> >
> > see e.g. https://tex.stackexchange.com/a/515934/2388
>
> Thank you, that is good news!
>
> At this point, what are the advantages of Xe(La)TeX vs. Lua(La)TeX?
> Apart from the crash Andrew reported, and the staleness of XeTeX's
> development.  Or maybe putting it differently, are there any situations
> that require XeTeX?
>
According to documentation it seems to me that ucharclasses work only
with XeLaTeX. If I use longer texts, I prefer polyglossia because I
need hyphenation. However, if I just want to insert single words, it
is simpler with ucharclasses.

> Mike Maxwell
>

Zdeněk Wagner
https://www.zdenek-wagner.eu/