token.set_macro: \directlua vs. luacode*

Question

If I compile the following code with LuaLaTeX I get the word "RED" as output. The call of token.set_macro inside of luacode* seems to be noneffective.

\listfiles
\documentclass{minimal}
\usepackage{luacode}

\newcommand*\foo{RED}

\iftrue
\begin{luacode*}
  token.set_macro('foo', 'GREEN')
\end{luacode*}
\else  
  \directlua{token.set_macro('foo', 'GREEN')}
\fi  

\begin{document}
  \foo
\end{document}

After changing \iftrue to \iffalse I get "GREEN". Can anyone explain this behavior? Many thanks.

Of course as a workaround it's possible to define a function in the luacode and call that function in directlua, so it's executed at the current TeX grouping level. // See also: luatex - token.set_macro: \directlua vs. luacode* - TeX - LaTeX Stack Exchange (same answer but uses tex.print to print the \def to TeX) — user202729, Jan 06 '22 at 06:27
Remark, it's possible for the package to "fix" that, see scoping - How can I escape the scope of an environment? - TeX - LaTeX Stack Exchange — user202729, Mar 26 '22 at 07:54

score 6 · Accepted Answer · answered Dec 12 '18 at 08:00

6

An environment is a group, if you add a group in the \directlua case, then you see the same:

\listfiles
\documentclass{minimal}
\usepackage{luacode}

\newcommand*\foo{RED}

\iffalse
\begin{luacode*}
  token.set_macro('foo', 'GREEN')
\end{luacode*}
\else
{  
  \directlua{token.set_macro('foo', 'GREEN')}
}
\fi  

\begin{document}
  \foo
\end{document}

answered Dec 12 '18 at 08:00

David Carlisle

757,742

1

Oh, so easy is the explanation. I must write token.set_macro('foo', 'GREEN', 'global'). Many thanks, David. – rolfn Dec 12 '18 at 08:24
1

@rolfn you could, although personally I'm not convinced by the need for the luacode environments, and I'd probably use \directlua directly. – David Carlisle Dec 12 '18 at 08:57

token.set_macro: \directlua vs. luacode*

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