%%
%% The LaTeX Companion, 3ed
%%
%% Example 4-1-21 on page I-272 in "The placement of the item label or item text".
%%
%% 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{135.0pt}


\usepackage{enumitem}
\SetLabelAlign{right}{\hss\setlength\fboxsep{0pt}\framebox[\labelwidth][r]{\strut\llap{#1}}}

%StartShownPreambleCommands
 \usepackage{enumitem}
 \setlist[enumerate]{label=--\arabic*--}
%StopShownPreambleCommands

\begin{document}
 \noindent Some text to show the left margin.
 \begin{enumerate}
   \item The default.
 \end{enumerate}
 \begin{enumerate}[leftmargin=*,start=2]
   \item One digit labels are set flushleft on the margin.
 \end{enumerate}
 \begin{enumerate}[leftmargin=*,start=33]
   \item But labels with 2 digits protrude.
 \end{enumerate}
 \begin{enumerate}[leftmargin=*,widest=99,start=42]
   \item  Here we tell to leave space for 2 digits.
 \end{enumerate}
\end{document}