[luatex] feature request: absolute path of main tex file

[Élie Roux]

Dear All,

For a project, I need to make a few convoluted checks and treatments
before including some files. The problem comes when the path to this
included file is relative, and when compilation occurs outside the
directory of the main .tex file. In this case \jobname is just the
filename, and lfs.currentdir() is the directory where the compilation
occurs, but it's not enough to know where the main .tex file really is.

Is there a way to get to know the absolute directory of the main .tex
file in luatex (argument string parsing maybe?)? If not would it be
reasonable to create one?

Thank you,
-- 
Elie