l3keys: how to "generate" `.inherit:V` variant of `.inherit:n`

Question

From the documentation,

⟨key⟩ .inherit:n = {⟨parents⟩}
Specifies that the ⟨key⟩ path should inherit the keys listed as ⟨parents⟩.

Because may parents are collected in \l_MY_parents_clist, I would benefit from

⟨key⟩ .inherit:V = \l_MY_parents_clist,

Unfortunately, the .inherit:V key variant does not exist, what can I do instead?

Below is a working code that uses an auxiliary function to create a keyval list from scratch and an auxiliary variable to store it. Isn't there something more efficient?

% !TeX program = lualatex
\documentclass{article}
\begin{document}
\noindent
\ExplSyntaxOn
\clist_set:Nn \l_tmpa_clist { parent, grand_parent }
\cs_set:Npn \MY_helper:Nn #1 #2 {
  \tl_put_right:Nn #1 {
    child .inherit:n = { #2 },
  }
}
\tl_clear:N \l_tmpa_tl
\exp_args:NNV
\MY_helper:Nn \l_tmpa_tl \l_tmpa_clist
\exp_args:NnV 
\keys_define:nn { } \l_tmpa_tl
TESTING:\
\keys_define:nn { parent } {
  test .code:n = TEST: #1\,
}
\keys_set:nn { child } {
  test = blah,
}
\keys_define:nn { grand_parent } {
  grand-test .code:n = GRAND-TEST: #1\,
}
\keys_set:nn { child } {
  grand-test = blah,
}
\end{document}

Although key properties have expl3-like signatures, they have to be created internally a bit differently (as keyvals need delimited macros). As such, there's no interface to add this, although I can look at including in the next expl3 release. — Joseph Wright, Mar 07 '22 at 12:02

score 1 · Accepted Answer · edited Mar 07 '22 at 12:10

1

You could structure it more like

\documentclass{article}
\begin{document}
\ExplSyntaxOn
\clist_set:Nn \l_tmpa_clist { parent, grand_parent }
\cs_set:Npn \MY_helper:nnn #1 #2 #3 {
     \keys_define:nn { #1 } {#2 .inherit:n = { #3 }}
  }
\cs_generate_variant:Nn \MY_helper:nnn {nnV}
\MY_helper:nnV {} {child} \l_tmpa_clist
TESTING:\
\keys_define:nn { parent } {
  test .code:n = TEST: #1\,
}
\keys_set:nn { child } {
  test = blah,
}
\keys_define:nn { grand_parent } {
  grand-test .code:n = GRAND-TEST: #1\,
}
\keys_set:nn { child } {
  grand-test = blah,
}
\end{document}

edited Mar 07 '22 at 12:10

Jérôme LAURENS

816

answered Mar 07 '22 at 11:20

David Carlisle

757,742

Nice, To make this more general, \MY_helper:n could become \MY_helper:nnn where the and the are parameters – Jérôme LAURENS Mar 07 '22 at 11:37
@JérômeLAURENS edit added – David Carlisle Mar 07 '22 at 12:10

l3keys: how to "generate" `.inherit:V` variant of `.inherit:n`

1 Answers1