Ogni tanto ritorno. Texlive 2022 aggiornata a oggi, il codice
`\documentclass[10pt]{book}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{imakeidx}
\makeindex
\makeatletter
\def\accents@list{\do\IeC\do\`\do\'}
\def\letters@list{\do\i{i}}
\newcommand{\noaccentindex}[1]{%
\begingroup
\let\UTF@two@octets@noexpand\@empty
\let\UTF@three@octets@noexpand\@empty
\let\UTF@four@octets@noexpand\@empty
\protected@edef\next{#1}%
\ifnum\pdfstrcmp{\detokenize\expandafter{\next}}{\detokenize{#1}}=\z@
\endgroup\index{#1}%
\else
\def\do##1{\def##1####1{####1}}\accents@list
\def\do##1##2{\def##1{##2}}\letters@list
\edef\next{\endgroup\def\noexpand\next{\next}}\next
\expandafter\index\expandafter{\next @\detokenize{#1}}%
\fi}
\makeatother
\begin{document}
ciao\noaccentindex{arto}
rete\noaccentindex{èna}
remo\noaccentindex{era}
\printindex
\end{document}`
dà ancora il problema di non creare la struttura `\indexentry{ena@èna}{1}` nell’idx.
@egreg9 hai qualche altra magia da tirare fuori?