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The general idea is that I can get the relative path of my project root by including the package mymacros.sty in my subprojects. I have the following setup:

  • mymacros.sty
  • myimg
    • figure.tikz

the content of mymacros.sty looks like this:

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{mymacros}
\RequirePackage{xparse}

\NewExpandableDocumentCommand \projectabspath {}
{%
  \directlua{tex.print(file.pathpart(file.addsuffix(file.collapsepath("\@currname"),'sty')))}%
}

I'm extracting the relative path from the \@currname macro with lua.

When I call the macro in my file figure.tikz

\documentclass{standalone}
\RequirePackage{luatex85}

\usepackage{../mymacros}
\typeout{\projectabspath}

\begin{document}
absolute path: \projectabspath
\end{document}

I get an empty path. What is the problem with my code?

Reza
  • 1,798

1 Answers1

3

To quote David Carlisle:

The argument of \usepackage is a name not a file path. The fact that it sometimes works at all when passed a relative file path is just due to lack of error checking by the system. If the package does declare itself using \ProvidesPackage the use of such paths will generate a warning that the name is incorrect.

Let's ignore that for a second and see why your code does not work:

You get the value of \@currname at the point the macro is expanded, which is in the middle of your document. There is no current package at that point, so \@currname is empty.

To fix this you have to expand \projectabspath while reading the package. You can use \edef to archive this:

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{mymacros}

\edef \projectabspath
{%
  \directlua{tex.print(file.pathpart(file.collapsepath("\@currname", true)))}%
}

or define the macro directly from Lua:

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{mymacros}

\directlua{
  token.set_macro('projectabspath', file.pathpart(file.collapsepath(token.scan_string(), true)))
}\@currname

Note that I added , true to collapsepath, otherwise the returned path is not absolute.

In general LuaTeX provides a more reliable way to get the path of the current file that analyzing \@currname: Use status.filename.

    \NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{mymacros}

\directlua{
  token.set_macro('projectabspath', file.pathpart(file.collapsepath(status.filename, true)))
}
Marcel Krüger
  • 34,151