% Test fixes for the LGR font encoding
\documentclass[a4paper,oneside]{book}

\pagestyle{headings}

\usepackage[LGR,T1]{fontenc}
\usepackage{lmodern}

% Play with the modifiers and watch the effects:
\newcommand*{\greeklanguagespecifier}{%
  % greek%
  greek.local-LGR-fixes%
  % greek.no-LGR-fixes%
}

\usepackage[\greeklanguagespecifier,english]{babel}

% hyperref and makeindex both have special requirements for \@roman & \@Roman
\usepackage{hyperref}
\hypersetup{unicode, colorlinks=true,linkcolor=blue,urlcolor=blue}
\usepackage{makeidx}
\makeindex


\begin{document}

% Pagenumbering uses Roman numerals in the front matter for "book" class
\frontmatter

\tableofcontents
% Check Roman page numbers!

\chapter{Preface \label{ch:preface}}

This document tests workarounds for the non-standard LGR Greek text font
encoding for \emph{necessity}, \emph{effects}, and \emph{side-effects}.

The ideal result would be that all Roman numerals came out as expeced
and the Index would contain two entries.

The new language attributes \texttt{local-LGR-fixes} and
\texttt{no-LGR-fixes} provide a tradeoff: limiting the work-arounds to local
scope or skipping them completely helps with the index but breaks some of
the Roman numbers. This can help in documents using only small Greek text
parts. In the current compilation, Babel is called with the
\texttt{\greeklanguagespecifier} and \texttt{english} options.

In this document, English text in Greek text parts is not protected against
the Greek transliteration (deliberately, to show clearly where Greek is the
active language). See the source \texttt{*.tex} file for the English
original.

\begin{enumerate}
  \item Problem
  \begin{enumerate}
    \item Roman numerals require Latin characters.
    \item Alphabetic counters use Latin characters, too.
    \item
      In document parts using the LGR font encoding, this leads to errors.
    \begin{enumerate}
      \item While an ``i'' is still recognizable after conversion to a
            small Iota, a ``v'', say, becomes an invisible no-break space.
      \item The transliteration of ``a) b) c) d) e) f) g)''
            leads to strange results, too.%
	    \label{item with roman number}
    \end{enumerate}
  \end{enumerate}
  \item Solution for (a): wrapping roman numbers in \verb|\ensureascii|.
  \begin{enumerate}
    \item However, some numbers, e.g. page numbers are auto-generated
          at ``unpredictible'' places.
          Other are used at places ``inaccessible'' to the author (e.g. the
          page number of a Greek chapter in the ToC).

          → Re-define counter-formatting functions to make them LGR-proof.

    \item Moving arguments complicate the matter.
    \begin{enumerate}
      \item The proofing must be robust (to some degree) to fix, e.g.,
            a Roman page number of a Greek chapter in the ToC.
      \item The proofing must be global to work reliably.
    \end{enumerate}
  \end{enumerate}
  \item Side-effect: the proofing makes Makeindex fail if there are
        index entries on pages with Roman numbering.

	\index{makeindex-problem}
        Makeindex expects ``pagenumbers'' to be simple text strings, without
	font encoding change or similar. Cf.
	\href{https://github.com/latex3/babel/issues/170}{Babel issue~\#170}.

\end{enumerate}


\selectlanguage{greek}
\chapter{Προλογος \label{ch:prologos}}

\begin{enumerate}
  \item Problem
  \begin{enumerate}
    \item Roman numerals require Latin characters.
    \item Alphabetic counters use Latin characters, too.
    \item
      In document parts using the LGR font encoding, this leads to errors.
    \begin{enumerate}
      \item While an ``i'' is still recognizable after conversion to a
            small Iota, a ``v'', say, becomes an invisible no-break space.
	    \index{invisible-v-problem}
      \item A transliteration of ``a) b) c) d) e) f) g)''
            leads to strange results, too.%
	    \label{item with roman number greek}
    \end{enumerate}
  \end{enumerate}
\end{enumerate}

% \newpage
% Second page of the Greek preface.

\selectlanguage{english}


\mainmatter

\chapter{First Chapter \label{ch:1}}

\section{Page references}

The ``preface'' is at page \pageref{ch:preface}.
The ``\ensuregreek{prologos}'' is at page \pageref{ch:prologos}.

\section{Page references from a Greek text part}

\selectlanguage{greek}

Ο ''\ensureascii{preface}'' βρίσκεται στη σελίδα
 \pageref{ch:preface}.
Ο ``πρόλογος'' βρίσκεται στη σελίδα \pageref{ch:prologos}.

\selectlanguage{english}

\begin{itemize}
\item With ``local-LGR-fixes'', the page number of the \ensuregreek{Προλογος}
      comes out wrong.
\item Authors can fix it by wrapping the \verb|\pageref| function.
      However, a change of the the default ``LGR fix scope'' to ``local''
      may break existing documents.
\end{itemize}


\section{References to items in an enumeration}

See item \ref{item with roman number} in an English list.
See item \ref{item with roman number greek} in a Greek list.

\section{References to items in an enumeration from a Greek text part}

\selectlanguage{greek}

See item \ref{item with roman number} in an English list.
See item \ref{item with roman number greek} in a Greek list.

\selectlanguage{english}

\begin{itemize}
\item The ``alph'' counter in the ``English'' list comes out wrong.
      (This is also the behaviour in previous versions of babel-greek.)
\item Authors must treat references to non-Greek text parts similar to
      non-Greek words and abbreviations (wrap in \verb|\ensureascii|).
\end{itemize}

\section{The Index}

The next page should show an Index with 2 entries
(see \texttt{test-lgr-fixes.idx}).

\begin{itemize}
\item With global LGR fixes, no index entry is printed (both are rejected by
      \texttt{makeindex} because of the font encoding change command
      preceding the page number.
\item With ``local-LGR-fixes'', only ``makeindex-problem'' is rejected.
      (The pagenumber is generated when the \verb|\chapter| command starts
      the \ensuregreek{Prologos} on a new page. At this point, the active
      language is Greek and the font encoding LGR.)
\end{itemize}

\backmatter
\printindex

\end{document}