%%
%% The LaTeX Companion, 3ed
%%
%% Example 3-4-19 on page I-190 in "ulem --- Emphasize and copy-edit via underline".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{123.0pt}

  \setlength\emergencystretch{5pt}   % narrow measure

%StartShownPreambleCommands
\usepackage[normalem]{ulem}
\useunder{\uwave}{\itshape}{\textit}
\useunder{\uline}{\bfseries}{\textbf}
\useunder{\uuline}{\ttfamily}{\texttt}
%StopShownPreambleCommands

\begin{document}
Historically speaking, \texttt{expl3} is an acronym for
\textbf{EX}perimental \textbf{P}rogramming \textbf{L}anguage
\textbf{3} even though it is a \textit{production lan\-guage}.
\end{document}