clarified ML_Context.expression: it is a closed expression, not a let-declaration -- thus source positions are more accurate (amending d8849cfad60f, 162a4c2e97bc);
\ProvidesPackage{ttbox}[1997/06/25]
\RequirePackage{alltt}
%%%Boxed terminal sessions
%Redefines \{ and \} to be in \tt font and \| to make a BACKSLASH
\def\ttbraces{\chardef\{=`\{\chardef\}=`\}\chardef\|=`\\}
%Restores % as the comment character (especially, to suppress line breaks)
\newcommand\comments{\catcode`\%=14\relax}
%alltt* environment: like alltt but smaller, and with \{ \} and \| as in ttbox
\newenvironment{alltt*}{\begin{alltt}\footnotesize\ttbraces}{\end{alltt}}
%Indented alltt* environment with small point size
%NO LINE BREAKS are allowed unless \pagebreak appears at START of a line
\newenvironment{ttbox}{\begin{quote}\samepage\begin{alltt*}}%
{\end{alltt*}\end{quote}}
{\obeylines\gdef\ttbreak
{\allowbreak}}
%%%% more \tt things
\def\ttdescriptionlabel#1{\hspace\labelsep \tt #1}
\def\ttdescription{\list{}{\labelwidth\z@ \itemindent-\leftmargin
\let\makelabel\ttdescriptionlabel}}
\let\endttdescription\endlist
\chardef\ttilde=`\~ % A tilde for \tt font
\chardef\ttback=`\\ % A backslash for \tt font
\chardef\ttlbrace=`\{ % A left brace for \tt font
\chardef\ttrbrace=`\} % A right brace for \tt font
\chardef\ttlbrack=`\[ % A left bracket for \tt font
\chardef\ttrbrack=`\] % A right bracket for \tt font
\newcommand\out{\ \ttfamily\slshape} %% for output from terminal sessions
\endinput