\glet not defined?

[kberry]

A few packages (including one very recent one, aspen) use \glet, and it's mentioned in expl3-code.tex, but apparently not defined? Is this as intended?
Thanks.

$ latex \\glet
This is pdfTeX, Version 3.141592653-2.6-1.40.29 (TeX Live 2026) (preloaded format=latex)                                                                       
 restricted \write18 enabled.                                                   
entering extended mode                                                          
LaTeX2e <2025-11-01>                                                            
L3 programming layer <2026-01-19>                                               
! Undefined control sequence.                                                   
<*> \glet      

(Cut off the long lines in these grep matches, doesn't matter).

$ grep -anHw '\\glet' -r .
biblatex-apa/apa.cbx:645:   \glet\textcitei\textcite
biblatex-apa/apa.cbx:646:   \glet\parencitei\parencite
delimtxt/delimtxt.sty:96:     \glet\InputBuffer=\empty%
delimtxt/delimtxt.sty:140:        \glet\InputBuffer=\empty}%
gmdoc/gmdoc.sty:336:    \glet\@currentlabel=\gmd@currentlabel@before% we restor$
gmdoc/gmdoc.sty:646:      \glet\settexcodehangi=\@@settexcodehangi%\\
gmdoc/gmdoc.sty:1333:      {\glet\gmd@maybequote\quotechar}%
gmdoc/gmdoc.sty:2459:  \glet\stored@code@delim\code@delim
gmdoc/gmdoc.sty:2858:  \glet\sgtleftxii=<}
gmdoc/gmdoc.sty:2902:  \glet\sgtleftxii=<
gmdoc/gmdoc.sty:3475:    \glet\@evenfoot\@oddfoot}% \label{oneside}anyway, it's$
gmdoc/gmdoc.sty:3480:    \glet\@evenfoot\@oddfoot}%
gmdoc/gmdoc.sty:3494:  \glet\@evenfoot\@oddfoot% see line \ref{oneside}.
gmutils/gmmw.sty:191:      \glet\gmu@checkaftersec@resa\mw@HeadingBreakAfter}% $
l3kernel/expl3-code.tex:958:  \__kernel_primitive:NN \glet                  \te$
aspen/aspen.sty:1023:\glet\steplabel\label

[u-fischer]

It is a luatex primitive.

apa.cbx e.g. uses it like this:

\ifdef\luatexversion
  {\directlua{require'apa'}%
   \glet\textcitei\textcite
   \glet\parencitei\parencite
   \gdef\textcite{\BLTXAPAifInParensTF{\nptextcite}{\textcitei}}%
   \gdef\parencite{\BLTXAPAifInParensTF{\nptextcite}{\parencitei}}}
  {}

I didn't check the other.

[josephwright]

We could I guess use it to define \cs_gset_eq:NN ...

[cfr42]

delimtxt.sty just defines it unconditionally, so will overwrite the primitive,

\def\glet{\global\let}

gmdoc.sty, gmmw.sty and aspen.sty all seem to use it without checking whether it exists.

[FrankMittelbach]

it is defined unconditionally in gmbase, so I guess only aspen.sty and apa.cbx has a problem.

Given that we have

  \__kernel_primitive:NN \glet                  \tex_glet:D

we might want to provide a version of \tex_glet:D that works with other engines (but not sure that is really necessary or helpful) and yes we could use it in \cs_gset_eq:NN for the luatex engine as a tiny speed improvement (assuming that it is actually faster to use the primitivce compared to two tokens). But none of this feels essential.