Biblatex indexing works very well with latin names. But when an author has foreign name (Łukasiewicz) the Ł letter is changed to \IeC {\L} and makeindex is not able to sort it well. In Polish it should be placed after L and before M (AĄ...CĆ...EĘ...LŁ...NŃ...OÓ...SŚ...ZŹŻ).
The problem does not exist with titles indexing using:
\DeclareIndexFieldFormat{indextitle}{\index[tit]{#1}}
(As far as I understand the problem is related with \protected@edef in \newbibmacro*).
Probably in other languages someone can have similar problem and knows the solution how to put in the idx file
\indexentry {Łukasiewicz|hyperpage}{123}
Here is a small example of a.tex source:
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[OT4]{fontenc}
\usepackage{filecontents}
\usepackage[style=authortitle-icomp,indexing=true,,backend=biber]{biblatex}
\DeclareIndexFieldFormat{indextitle}{\index[tit]{#1}}
\bibliography{a}
\usepackage{index}
\newindex{default}{idx}{ind}{Index}
\newindex{tit}{tdx}{tnd}{Titles}
\begin{document}
\begin{filecontents}{\jobname.bib}
@Book{Xauthor,
author = {Śauthor},
title = {Śauthor's Book}
}
@Book{Sauthor,
author = {Sauthor},
title = {Sauthor's Book}
}
@Book{Tauthor,
author = {Tauthor},
title = {Tauthor's Book}
}
\end{filecontents}
\section*{Polish sort order ...SŚT...}
\nocite{*}
\printbibliography
\printindex[default]
\printindex[tit]
\end{document}
and the small script
export LANG=pl_PL.utf8
latex a
biber a
latex a
makeindex -L a.idx -o a.ind
makeindex -L a.tdx -o a.tnd
latex a
xdvi a.dvi
In the a.idx we have problematic:
\indexentry {\IeC {\'S}author}{1}
in a.tdx we have correct:
\indexentry {Śauthor's Book}{1}
so we get correct order in biber (References) and Titles but wrong in Index (Śauthor is before Sauthor).
makeindexis working well withutf8andlocales. The problem is thatbiblatexis generating two types of\indexentry: one correct for titles (utf8) and the second usingIeC {...}for names which creates problems. Because the general utf8biberandmakeindexbehavior is correct, the problem is rather withbiblatexwhich is inconsistent in this subject (generates two types of\indexentry). – zeta0 Jul 10 '11 at 09:47