Re: [Dev-luatex] Problem with directlua and synctex_tag

29 Mar 2022


      I think I know understand what is really meant by "obeys save stack" in the documentation, but that was not easy to catch due to 3 bugs in the implementation: contrary to the documentation

1 - force_synctex_tag obeys save stack
2 - set_synctex_line does not obey save stack
3 - force_synctex_line obeys save stack

\directlua{
tex.set_synctex_tag(11)
tex.set_synctex_line(22)
}\def\MyMacro{
\directlua{
tex.set_synctex_tag(111)
tex.set_synctex_line(222)
}}
\MyMacro
\directlua{
print("SUCCESS 11 expected:", tex.get_synctex_tag())
print("FAILURE 22 expected:", tex.get_synctex_line())
}
\directlua{
tex.set_synctex_tag(11)
tex.set_synctex_line(22)
}
\def\MyMacro{
\directlua{
tex.force_synctex_tag(111)
tex.force_synctex_line(222)
}}
\MyMacro
\directlua{
print("FAILURE 111 expected:", tex.get_synctex_tag())
print("FAILURE 222 expected:", tex.get_synctex_line())
}
\bye
...
Le 28 mars 2022 à 21:09, Jérôme LAURENS  a écrit :
I have a better understanding now, but the problem still remains that synctex_tag and synctex_line are not managed accordingly,
as illustrated by all the examples given so far.
My first thinking was that synctex_tag behavior should follow synctex_line behavior, now it clearly appears that synctex_line should follow synctex_tag instead.
Consider next code
```
\directlua{
tex.set_synctex_tag(99)
tex.set_synctex_line(299)
}
\MyMacro
\directlua{
print(tex.get_synctex_tag())
print(tex.get_synctex_line())
}
\bye
```
Whatever \MyMacro is, synctex_tag is 99, but synctex_line is unpredictable.
That is a problem.
...
Le 28 mars 2022 à 19:46, Marcel Fabian Krüger  a écrit :
On Mon, Mar 28, 2022 at 06:53:30PM +0200, Jérôme LAURENS wrote:
...
Things seem not as simple as you suggest, at least on luatex 1.13.2.
In next example, synctex_tag and synctex_line both survive the first \directlua call, so the state is not gone, which is a good thing
\directlua{
tex.set_synctex_tag(99)
print(tex.get_synctex_tag())
tex.set_synctex_tag(199)
tex.set_synctex_line(299)
print(tex.get_synctex_line())
tex.set_synctex_line(399)
}
\directlua{
print(tex.get_synctex_tag())
print(tex.get_synctex_line())
}
\bye
In next example where \directlua is called from a macro, synctex_line survives the call but not synctex_tag.
So some part of the state is gone, which is not practical.
\def\Setter{
\directlua{
tex.set_synctex_tag(99)
print(tex.get_synctex_tag())
tex.set_synctex_tag(199)
tex.set_synctex_line(299)
print(tex.get_synctex_line())
tex.set_synctex_line(399)
}
}
\Setter
\def\Getter{
\directlua{
print(tex.get_synctex_tag())
print(tex.get_synctex_line())
}
}
\Getter
\bye
As Hans wrote the tag is set for the current input level. A macro
expansion is a new input level, while \directlua in general is not
(except of course if new input is added from the Lua code)
- Marcel
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