acronym with inputenc changes between latin10 and utf8

Question

[edited] finished OK MWE

This is mwe.dtx.

% \iffalse    (METACOMMENT)
%%
%% ---------------------------------------------------------------------
%%
%% Document class `mwe' to use with LaTeX 2e.
%%
%% ---------------------------------------------------------------------
%%
% \fi
%
% \CheckSum{419}
%% \CharacterTable
%%  {Upper-case    \A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z
%%   Lower-case    \a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z
%%   Digits        \0\1\2\3\4\5\6\7\8\9
%%   Exclamation   \!     Double quote  \"     Hash (number) \#
%%   Dollar        \$     Percent       \%     Ampersand     \&
%%   Acute accent  \'     Left paren    \(     Right paren   \)
%%   Asterisk      \*     Plus          \+     Comma         \,
%%   Minus         \-     Point         \.     Solidus       \/
%%   Colon         \:     Semicolon     \;     Less than     \<
%%   Equals        \=     Greater than  \>     Question mark \?
%%   Commercial at \@     Left bracket  \[     Backslash     \\
%%   Right bracket \]     Circumflex    \^     Underscore    \_
%%   Grave accent  \`     Left brace    \{     Vertical bar  \|
%%   Right brace   \}     Tilde         \~}
%%
% ^^A \MakeShortVerb{\|}
% \section{Internals}
%
%    \begin{macrocode}
%<class>\NeedsTeXFormat{LaTeX2e}[1995/12/01]
%    \end{macrocode}
%
% \iffalse (Don't show this in the doc).
%<*driver>
         \ProvidesFile{mwe.drv}
%</driver>
% \fi
%    \begin{macrocode}
%<class>\ProvidesClass{./mwe}
        [2012/05/24 v1.0
%<class>        A mwe class]
%    \end{macrocode}
% \iffalse (Omitted from the doc)
%<*driver>
]
%</driver>
% \fi
%
% \subsection{Driver for this document}
%
% This program will extract the following driver from this file:
%    \begin{macrocode}
%<*driver>
\documentclass{ltxdoc}
\EnableCrossrefs
%\DisableCrossrefs % Say \DisableCrossrefs if index is ready
\RecordChanges
%\OnlyDescription % Comment out for implementation details
\CodelineIndex
\begin{document}
  \DocInput{mwe.dtx}
\end{document}
%</driver>
%    \end{macrocode}
% \begin{macro}{\my@op@n}
% \begin{macro}{\my@s@ut}
% \begin{macro}{\protected@write@immediate}
% \begin{macro}{\immediateaddtocontents}
% \begin{macro}{\addtocontentsline}
% \begin{macro}{\my@readwrite@line}
% \begin{macro}{\my@docum@nt}
% \begin{macro}{\my@end@docum@nt}
% \begin{environment}{document}
% \begin{macro}{\my@sym@def}
% \begin{macro}{\my@sym@LANG@def}
% \begin{macro}{\my@s@l@ctl@ngu@g@}
% \begin{macro}{\selectlanguage}
% \begin{macro}{\my@ch@pt@r@}
% \begin{macro}{\@chapter}
% \begin{environment}{symbols}
%    \begin{macrocode}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\RequirePackage[T1]{fontenc}%%%%
\RequirePackage[utf8]{inputenc}%
\RequirePackage{xargs}%%%%%%%%%%
\RequirePackage{acronym,suffix,xargs,xifthen,xspace}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\LoadClass[a4paper,10pt,twoside,openright]{report}[2007/10/19]

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\newcommandx\my@op@n[3][addprefix=\global,1=template,2=.txt,3=.tex]{%
  \newread\my@file%
  \immediate\openin\my@file=#1\myLANG#2%
  \newwrite\my@fil@%
  \immediate\openout\my@fil@=#1\myLANG#3%
}

\newcommandx\my@s@ut[0][addprefix=\global]{%
  \immediate\closein\my@file%
  \immediate\closeout\my@fil@%
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Code borrowed from `multitoc.dtx' of CTAN /macros/latex/contrib/ms
%% Copyright (c) [1998..1999]  Martin Schr\"oder. All rights reserved.

\newcommand*{\protected@write@immediate}[3]{%
      \begingroup
       \let\thepage\relax
       #2%
       \let\protect\string
       \edef\reserved@a{\immediate\write#1{#3}}%
       \reserved@a
      \endgroup
      \if@nobreak\ifvmode\nobreak\fi\fi
   }

\newcommand*{\immediateaddtocontents}[2]{%
  \protected@write@immediate\@auxout
      {\let\label\@gobble \let\index\@gobble \let\glossary\@gobble}%
      {\string\@writefile{#1}{#2}}}

%%
%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\def\addcontentsline#1#2#3{%
  \immediateaddtocontents{#1}{\protect\contentsline{#2}{#3}{\thepage}}}

\newcommandx\my@readwrite@line[2][addprefix=\global\protect,1=-1,2=to]{%
  \catcode`\\=12\catcode`\{=12\catcode`\}=12\catcode`\$=12%
  \catcode`\#=12\catcode`\^=12\catcode`\_=12\catcode`\%=12%
  \let\my@var\endlinechar%
  \endlinechar=#1%
  \immediate\read\my@file#2\my@lin@%
  \endlinechar=\my@var%
  \catcode`\%=14\catcode`\_=8\catcode`\^=7\catcode`\#=6%
  \catcode`\$=3\catcode`\}=2\catcode`\{=1\catcode`\\=0%
  \protected@xdef\my@line{\my@lin@}%
  \ifthenelse{\equal{\my@line}{}}{}{%
  \protected@write@immediate\my@fil@{\relax}{\my@line\@backslashchar\@backslashchar}}%
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\let\my@docum@nt\document
\let\my@end@docum@nt\enddocument
\renewenvironmentx{document}[2][1=pre,2]{%
  \my@op@n%
  \my@docum@nt%%%%%
  \input{#1.tex}%
  \ifx\\#2\\\else\selectlanguage{#2}\fi%
  \ignorespaces%%%%%%%%%
}{\my@end@docum@nt%
  \ignorespacesafterend%
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\newcommandx\my@sym@def[1][addprefix=\global]{%
  \expandafter%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \newcommandx\csname#1\endcsname[4][addprefix=\global,3,4]{%
    \ifthenelse{\isempty{##3}%
    }{\ifthenelse{\isempty{##4}%
      }{\acro{##1}{{##2}}%%%%%%%%%
      }{\acro{##1}[{##2}]{{##4}}}%
    }{\ifthenelse{\isempty{##4}%
      }{\acro{##1}{{##2}\acroextra{{##3}}}%%%%%%%%
      }{\acro{##1}[{##2}]{{##4}\acroextra{{##3}}}%
    }}%
    \expandafter\gdef\csname##1\endcsname{\acl{##1}\xspace{}}%%
    \expandafter\gdef\csname##1*\endcsname{\acs{##1}\xspace{}}%
  }%
}

\newcommandx\my@sym@LANG@def[2][addprefix=\global]{%
  \expandafter%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \newcommandx\csname#1#2\endcsname[4][3,4]{%
    \ifthenelse{\isempty{##3}%%%%%%%%%%%%%%%%%%%%%%%
    }{\@nameuse{#1}{##1}{\@nameuse{#2}{##2}}[][##4]%
    }{\@nameuse{#1}{##1}{\@nameuse{#2}{##2}}%%%%%%%%
                        [\@nameuse{#2}{##3}][##4]%%%
    }%
  }%
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\let\my@s@l@ctl@ngu@g@\selectlanguage
\renewcommand\selectlanguage[1]{%%%%%%%%%%%
\my@s@l@ctl@ngu@g@{#1}\@nameuse{do\myLANG}}

\let\my@ch@pt@r@\@chapter
\renewcommandx\@chapter[3][1,2,3]{%
  \ifthenelse{\isempty{#1}}{%
    \GenericError{}{empty chapter name}{%%%
      stop}{%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
      here.}}%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \ifx\\#3\\\else\selectlanguage{#3}\fi%
  \my@ch@pt@r@[#1]{#1}%
  \addcontentsline{lof}{chapter}{\thechapter\nobreakspace#1}%
  \addcontentsline{lot}{chapter}{\thechapter\nobreakspace#1}%
  \ifx\\#2\\\else\label{chp:#2}\fi%
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\newenvironmentx{symbols}[1][1]{%
  \pagestyle{empty}%%%%%%%
  \thispagestyle{empty}%%%
  \chapter*{Symbols}%
  \addcontentsline{toc}{section}{Symbols}%
  \begin{acronym}[{#1}]%
}{\end{acronym}%%%%%%%%%
  \clearpage%
}

%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{environment}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{environment}

This is mwe.ins.

\def\batchfile{mwe.ins}
\input docstrip.tex
\keepsilent
\generateFile{mwe.cls}{t}{\from{mwe.dtx}{class}}

This is ltxdoc.cfg.

\PassOptionsToClass{a4paper}{article}
\AtEndOfPackage{%
\hyphenation{tocprelim semifinal draft}
\RequirePackage{indentfirst}%
\RequirePackage{hyperref}%
}

This is mwe.tex.

% -*- mode: latex; unibyte: nil; coding: utf-8 -*-

\documentclass{./mwe}

\usepackage[romanian]{babel}
\usepackage{newunicodechar}

\newunicodechar{ș}{\c{s}}\newunicodechar{Ș}{\c{S}}
\newunicodechar{ț}{\c{t}}\newunicodechar{Ț}{\c{T}}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\newcommand\RO[1]{\foreignlanguage{romanian}{#1}\xspace{}}
\newcommand\doRO{\relax}
\xdef\myLANG{RO}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\makeatletter

\my@sym@def{sym}
\@expandtwoargs\my@sym@LANG@def{sym}{\myLANG}

\makeatother

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\title{Minimal Working Example}
\author{acronym}

\begin{document}[preamble][romanian]

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%--------------------------------------------------------------------%

\inputencoding{latin10}

\makeatletter

\newcounter{my@cnt}%
\setcounter{my@cnt}{0}%

\@whilenum\arabic{my@cnt}<24\do{%
  \my@readwrite@line%
  \stepcounter{my@cnt}%
}

\my@s@ut%

\makeatother

\noindent%
\input{templateRO}

\inputencoding{utf8}

%--------------------------------------------------------------------%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\chapter[Oscilații][osc][romanian]

\HZO~e formula pentru \HZO*.

\end{document}

This is preamble.tex.

% -*- mode: latex; unibyte: t; coding: utf-8 -*-

\maketitle

\begin{symbols}[WORD]

  \symRO{HZO}{Apă}[\hfill făcută din 3 elemente și 2 molecule][$H_2O$]

\end{symbols}

\tableofcontents

The sequence is: latex mwe.ins; pdftex -shell-escape mwe.tex #twice

The file templateRO.txt as specified here -- http://en.wikipedia.org/wiki/Romanian_alphabet#Unicode_and_HTML -- contains 8-bit letters with commas, not cedillas.

Thesis
Submitted in Partial Fulfillment of the Requirements for
the Degree of Doctor of Philosophy
in Computer Science
to the Faculty of Engineering of the
University of Rome
by

Conducător științific
Referenți științifici

Ziua susținerii tezei

Acest document este în domeniul public.

Acknowledgements

Dedicație

Keywords

Lista de acronime
Lista de teoreme
Lista de demonstrații

thank s.

Answer 1

The main file should not have the catcode changes they disable inputenc

\documentclass[a4paper,10pt]{report}

\usepackage[T1]{fontenc}
\usepackage[latin10,utf8]{inputenc}
\usepackage[romanian]{babel}
\usepackage{newunicodechar}
\usepackage{acronym}

\newunicodechar{ș}{\c{s}}\newunicodechar{Ș}{\c{S}}
\newunicodechar{ț}{\c{t}}\newunicodechar{Ț}{\c{T}}

\begin{document}

\selectlanguage{romanian}

\inputencoding{latin10}


\input{symbols}



\inputencoding{utf8}

\chapter{Oscilații}

\end{document}

You will need to delete the .aux file so latex will then write a correct one that should look like this:

\relax 
\reset@newl@bel
\select@language{romanian}
\@writefile{toc}{\select@language{romanian}}
\@writefile{lof}{\select@language{romanian}}
\@writefile{lot}{\select@language{romanian}}
\select@language{romanian}
\@writefile{toc}{\select@language{romanian}}
\@writefile{lof}{\select@language{romanian}}
\@writefile{lot}{\select@language{romanian}}
\newacro{Ap\u a}[\AC@hyperlink{Ap\u a}{Ap\u a}]{f\u acut\u a din 3 elemente \tex
tcommabelow si 2 molecule}
\@writefile{toc}{\contentsline {chapter}{\numberline {1}Oscila\c {t}ii}{2}}
\@writefile{lof}{\addvspace {10\p@ }}
\@writefile{lot}{\addvspace {10\p@ }}

Note the aux file characters are never written as characters but using latex commands so they can be read back even if the file is using a different encoding at that point.