Translation centering with [/] fails to work when LuaTeX-ja is loaded

[anthonyfok]

Hi!

Sorry, it is me again with yet another LuaTeX-ja related issue, this time with centered translation with [/]. To test, I added a translation for one word in PopulusSion.gabc in the gregorio-test/tests/plain-tex/luatex-ja directory:

--- a/tests/tex-output/PopulusSion/PopulusSion.gabc
+++ b/tests/tex-output/PopulusSion/PopulusSion.gabc
@@ -17,7 +17,7 @@ style: modern;

 % The syntax in this part is called gabc. Please refer to http://home.gna.org/gregorio/gabc/#basis

-Pó(c3eh)pu(g)lus(h) Si(hi)on,(hgh.) *(;) ec(hihi)ce(e.) Dó(e.f!gwhhi)mi(h){n}us(h) vé(hi)ni(ig//ih)et(h.) (,) ad(iv./hig) sal(fe)ván(ghg)das(fg) gen(e_f_e_)tes(e.) :(:)
+Pó[People](c3eh)pu(g)lus[/](h) Si(hi)on,(hgh.) *(;) ec(hihi)ce(e.) Dó(e.f!gwhhi)mi(h){n}us(h) vé(hi)ni(ig//ih)et(h.) (,) ad(iv./hig) sal(fe)ván(ghg)das(fg) gen(e_f_e_)tes(e.) :(:)

 et(e) au(eh)dí(hhi)tam(i) fá(kjki)ci(i)et(i) Dó(ij)mi(ihi)nus(iv./hiHF) (,) gló(h!i'j)ri(ji!kvJI)am(ij) vo(j.i!jwk)cis(ji) su(i_j_i_)æ,(i.) (;) in(e) læ(e)tí(e!f'h)ti(h)a(hi!jVji)

luatex PopulusSion.tex runs fine until near the end:

(./PopulusSion-4_1_4.gtexerror: ...exlive/texmf-dist/tex/luatex/gregoriotex/gregoriotex.lua:325: attempt to index field 'head' (a nil value)
.
\GreEndScore ...re@localrightbox {}\fi \hfil \par 
                                                  \ifgre@keeprightbox \globa...

l.725 \GreEndScore
                 %
? 
) [1{/var/lib/texmf/fonts/map/pdftex/updmap/pdftex.map}])
Module gregoriotex Warning: Line heights or variable brace lengths may have cha
nged. Rerun to fix. on input line 0
</usr/share/texlive/texmf-dist/fonts/truety
pe/public/gregoriotex/greextra.ttf><../../../fonts/Alegreya-Regular.otf>{/usr/s
hare/texlive/texmf-dist/fonts/enc/dvips/base/8r.enc}</usr/share/texlive/texmf-d
ist/fonts/truetype/public/gregoriotex/greciliae.ttf></usr/share/fonts/truetype/
fonts-japanese-mincho.ttf></usr/share/texlive/texmf-dist/fonts/type1/public/ams
fonts/cm/cmr10.pfb></usr/share/texlive/texmf-dist/fonts/type1/public/amsfonts/c
m/cmti10.pfb></usr/share/texlive/texmf-dist/fonts/type1/urw/ncntrsbk/uncr8a.pfb
>
Output written on PopulusSion.pdf (1 page, 137324 bytes).
Transcript written on PopulusSion.log.

So, a PDF file is generated, except that the translation is not centered. No big deal though, as I can generate the desired output (Salve Regina, simple tone, with Chinese translation underneath) without LuaTeX-ja, so no hurries. :-)

Tested with Gregorio 4.1.4 that is included in TeX Live 2016 update. I haven't tried it with the Gregorio 4.2 branch yet.

Many thanks!

Anthony

[anthonyfok]

I think I found the culprit and the solution.

LuaTeX-ja inserts custom whatsit nodes to the beginning of node lists, breaking pre-determined node paths like startnode.head.next.head.next.head, which gets moved to startnode.head.next.next.head.next.next.head.next with luatexja loaded.

The log file shows the kinds of whatsit nodes that LuaTeX-ja create:

Normally, without luatexja:

Lua module: gregoriotex 2016/05/29 4.1.4 GregorioTeX module.
Custom whatsit marker = 1

With luatexja loaded:

Custom whatsit inhibitglue = 1
Custom whatsit stack_marker = 2
Custom whatsit begin_par = 3
Custom whatsit direction = 4
...
Lua module: gregoriotex 2016/05/29 4.1.4 GregorioTeX module.
Custom whatsit marker = 5

I have posted a proposed solution is at Pull Request #1201: to use node.traverse_id() to find the nodes of interest. Please review the PR at your convenience, and please feel free to change it in whatever ways you prefer to conform to the existing coding style in Gregorio.

Thanks again!

Anthony