% \iffalse meta-comment
% ======================================================================
% defoldfonts.dtx
% Copyright © 2008–2023 Markus Kohm
%
% Development of this work is taking place at
% <https://github.com/komascript/defoldfont>.  New issues should be
% reported there as well as known issues can be found.
%
% This work may be distributed and/or modified under the conditions of
% the LaTeX Project Public License, version 1.3c of the license.
% The latest version of this license is in
%   http://www.latex-project.org/lppl.txt
% and version 1.<3c or later is part of all distributions of LaTeX
% version 2005/12/01 or later and of this work.
%
% This work has the LPPL maintenance status "author-maintained".
%
% The Current Maintainer and author of this work is Markus Kohm.
%
% This work consists of the file `defoldfonts.dtx' and `README.md'.
%
% The recommended way to install `defoldfonts' is to use
% the package manager of your TeX distribution.
% ======================================================================
%
%<*dtx>
\ifx\ProvidesFile\undefined\def\ProvidesFile#1[#2]{}\fi
\ProvidesFile{defoldfonts.dtx}
%</dtx>
%<*dtx|package>
%<package>\ProvidePackage{defoldfonts}
  [2023-07-28 v1.0
%<dtx> sources and unpack driver of
  re-implementation of deprecated KOMA-Script code]
%<package>}
%</dtx|package>
%<*dtx>
\ifx\documentclass\undefined
  \input docstrip.tex
  \generate{%
    \file{defoldfonts.sty}{%
      \from{defoldfonts.dtx}{package}%
    }%
  }%
\else
  \let\endbatchfile\relax
\fi
\endbatchfile
\documentclass[ngerman,USenglish]{koma-script-source-doc}
\setcounter{IndexColumns}{2}  
\usepackage{babel}
\usepackage{csquotes}
\usepackage[style=alphabetic]{biblatex}
\begin{filecontents}[force]{\jobname.bib}
@online{pkg:koma-script,
  author={Markus Kohm},
  version={3.41},
  date={2023-07-07},
  title={{\KOMAScript} --- A bundle of versatile classes and packages},
  url={https://ctan.org/pkg/koma-script},
  urldate={2023-07-14},
  note={The \KOMAScript{} bundle provides replacements for the \pkg*{article},
        \pkg*{report}, and \pkg*{book} classes with emphasis on typography and
        versatility. There is also a letter class.},
}
@manual{pkg:koma-script:manual:de,
  author={Markus Kohm},
  date={2023-06-16},
  title={{\KOMAScript}},
  subtitle={Die Anleitung},
  url={http://mirrors.ctan.org/macros/latex/contrib/koma-script/scrguide-de.pdf},
  urldate={2023-07-04},
}
@manual{pkg:koma-script:manual:en,
  author={Markus Kohm},
  date={2023-06-16},
  title={{\KOMAScript}},
  subtitle={The Guide},
  url={http://mirrors.ctan.org/macros/latex/contrib/koma-script/scrguide-en.pdf},
  urldate={2023-07-14},
}
\end{filecontents}
\addbibresource{\jobname.bib}
\setcounter{StandardModuleDepth}{2}
\begin{document}
  \nocite{pkg:koma-script,pkg:koma-script:manual:en,pkg:koma-script:manual:de}
  \DocInput{defoldfonts.dtx}
\end{document}
%</dtx>
%\fi
%
% \changes{v0.1}{2023/06/01}{start of \KOMAScript{} spin-off}
%
% \GetFileInfo{defoldfonts.dtx}
% \title{Defining Old Font Commands}
% \author{\href{mailto:komascript@gmx.info}{Markus Kohm}}
% \date{Version \filedate{} \fileversion}
% \maketitle
% \begin{abstract}
%   The package defines the old font commands \cs{rm}, \cs{sf}, \cs{tt},
%   \cs{bf}, \cs{it}, and \cs{sc} that became obsolete with \LaTeXe{} and has
%   been removed from the \LaTeX{} kernel. It also defines the old
%   \href{https://komascript.de/}{\KOMAScript} font command \cs{sfb}. It can
%   be useful if you use a class like the
%   \href{https://komascript.de/}{\KOMAScript} classes, which do not define
%   the old commands by default, and also an old \BibTeX{} style or package,
%   that depends on these commands. However, it should be seen as an emergency
%   workaround rather than a solution.
% \end{abstract}
%
% \tableofcontents
%
%\iffalse
%<*doc>
%\fi
\section{What are the possible reasons for using package
  \texorpdfstring{\pkg*{defoldfonts}}{defoldfonts} and how to do it?}
\label{sec:reasons}

\DescribeCommand{\rm}%
\DescribeCommand{\sf}%
\DescribeCommand{\tt}%
\DescribeCommand{\bf}%
\DescribeCommand{\it}%
\DescribeCommand{\sl}%
\DescribeCommand{\sc}%
\DescribeCommand{\sfb}%
With \LaTeXe{} in 1994 the font commands of \LaTeX~2.09 became obsolete. These
are not longer defined in the \LaTeX{} kernel. Instead of them, you should use
\cs{rmfamily} resp. \cs{textrm}, \cs{sffamily} resp. \cs{textsf},
\cs{ttfamily} resp. \cs{texttt}, \cs{bfseries} resp. \cs{textbf}, \cs{itshape}
resp. \cs{textit}, \cs{slshape} resp. \cs{textsl}, and \cs{scshape}
resp. \cs{testsc}. The old \href{https://komascript.de/}{\KOMAScript} command
\cs{sfb} should be replaced by a combination of \cs{sf} and \cs{bf}
resp. \cs{textsf} and \cs{textbf}. But unfortunately not only some old
\BibTeX{} styles but even some packages still use these obsolete commands. The
standard classes therefore still define them. The
\href{https://komascript.de/}{\KOMAScript} classes also define them, but only
to show an error message like:
\begin{verbatim}
  Class scrartcl Error: undefined old font command `\bf'.

  See the scrartcl class documentation for explanation.
  Type  H <return>  for immediate help.
   ...                                              

  l.3 \bf
\end{verbatim}
Within an interactive \LaTeX{} run you can get some more information typing
\texttt{H} and pressing the \texttt{return} key:
\begin{verbatim}
  You should note that since 1994 LaTeX2e provides a new font selection scheme
  called NFSS2 with several new, combinable font commands. KOMA-Script
  classes had defined the old font commands like `\bf' only for compatibility
  with old LaTeX 2.09 document styles of Script 2.0. Nevertheless, these
  commands are deprecated and undocumented at least since 2003. Since 2013
  KOMA-Script classes warned about soon removement of these deprecated commands.
  Now, after two decades of LaTeX2e and NFSS2, these commands will not work any
  more. If loading a package results in this error message, you should contact
  the author of that package and ask him to replace the deprecated font command
  `\bf', e.g., by `\normalfont \bfseries `. Otherwise you should reconfigure
  or replace the package. If you have used the old font command `\bf' yourself,
  you should replace it, e.g., by `\normalfont \bfseries '.
  To make it work for now, you can use the already also deprecated class option
  `enabledeprecatedfontcommands'.
\end{verbatim}
So to fix the issue, you could load the class with option
\opt{enabledeprecatedfontcommands}. But because this option is also
deprecated, this would result in warning messages like:
\begin{verbatim}
  Class scrartcl Warning: deprecated option `enabledeprecatedfontcommands'.
  (scrartcl)              Note, that this option was already depreacted when
  (scrartcl)              it has been defined. Support for old font commands
  (scrartcl)              has been removed from KOMA-Script more than one
  (scrartcl)              decade ago. It is not recommended to use them any
  (scrartcl)              longer. Therefore usage of this class option also
  (scrartcl)              is not recommended.
\end{verbatim}
and:
\begin{verbatim}
  Class scrartcl Warning: deprecated old font command `\bf' used.
  (scrartcl)              You should note, that since 1994 LaTeX2e provides a
  (scrartcl)              new font selection scheme called NFSS2 with several
  (scrartcl)              new, combinable font commands. New KOMA-Script classes
  (scrartcl)              defined the old font commands like `\bf' only for
  (scrartcl)              compatibility with LaTeX 2.09 document styles of
  (scrartcl)              Script 2.0. These commands are deprecated and
  (scrartcl)              undocumented at least since 2003. Since 2013,
  (scrartcl)              KOMA-Script classes warned about soon removement of
  (scrartcl)              these deprecated commands. Now, after two decades of
  (scrartcl)              LaTeX2e, NFSS2, and KOMA-Script these commands will
  (scrartcl)              not work any longer. If loading a package results in
  (scrartcl)              this message you should contact the author of that
  (scrartcl)              package and ask him to replace the depracted font
  (scrartcl)              command `\bf', e.g., by `\normalfont \bfseries '.
  (scrartcl)              Otherwise you should reconfigure or replace the
  (scrartcl)              package. If you have used the old font command
  (scrartcl)              `\bf' yourself you should replace it, e.g., by
  (scrartcl)              `\normalfont \bfseries ' on input line ….
\end{verbatim}
As an alternative you can load package \pkg*{defoldfonts}.

The package should be loaded in the preamble using:
\begin{verbatim}
  \usepackage{defoldfonts}
\end{verbatim}
Usually the order of \pkg*{defoldfonts} and other packages is irrelevant.

% \iffalse
%</doc>
% \fi
%
% \MaybeStop{\printbibliography[heading=bibintoc]\PrintIndex}
%
% \iffalse
%<*package>
% \fi
% \section{Implementation}
% \label{sec:implementation}
%
%    \begin{macrocode}
\ProcessOptions\relax
%    \end{macrocode}
%
% \begin{command}{\rm,\sf,\tt,\bf,\it,\sl,\sc,\sfb}
% We define these commands without compromise:
%    \begin{macrocode}
\DeclareOldFontCommand{\rm}{\normalfont\rmfamily}{\mathrm}
\DeclareOldFontCommand{\sf}{\normalfont\sffamily}{\mathsf}
\DeclareOldFontCommand{\tt}{\normalfont\ttfamily}{\mathtt}
\DeclareOldFontCommand{\bf}{\normalfont\bfseries}{\mathbf}
\DeclareOldFontCommand{\it}{\normalfont\itshape}{\mathit}
\DeclareOldFontCommand{\sl}{\normalfont\slshape}{\@nomath\sl}
\DeclareOldFontCommand{\sc}{\normalfont\scshape}{\@nomath\sc}
\DeclareOldFontCommand{\sfb}{\normalfont\sffamily\bfseries}{\@nomath\sfb}
%    \end{macrocode}
% \end{command}
%
% \iffalse
%</package>
% \fi
%
% \Finale
% \PrintChanges
%  
% \endinput
% Local Variables:
% mode: doctex
% ispell-local-dictionary: "en_US"
% eval: (flyspell-mode 1)
% TeX-master: t
% End: