% Makes a 3-column landscape listing of one or more files
% Typical usage:
% tex 3list *.c \\end

\def\grabfile#1 {\setbox0=\lastbox\endgraf\doit{#1}}
\everypar{\grabfile}

\font\filenamefont= cmtt8 scaled\magstep3
\font\headlinefont= cmr8
\font\listingfont= cmtex8
\font\eoffont= cmti8

\def\today{\ifcase\month\or
 January\or February\or March\or April\or May\or June\or
 July\or August\or September\or October\or November\or December\fi
 \space\number\day, \number\year}
\newcount\m \newcount\n
\n=\time \divide\n 60 \m=-\n \multiply\m 60 \advance\m \time
\def\hours{\twodigits\n\twodigits\m}
\def\twodigits#1{\ifnum #1<10 0\fi \number#1}

\newlinechar=`@
\message{@\today\space at \hours}

\baselineskip=9pt
\medskipamount=4pt minus 1pt
\raggedbottom
\nopagenumbers

\chardef\other=12
\def\doit#1{\message{@Listing #1@}
 \begingroup \everypar{} \frenchspacing
 \headline{\ifright \headlinefont \hfill Page \folio
   \else\hbox to2.5in{\filenamefont#1\quad
          \headlinefont \today\ at \hours\hskip-3in\hss}\hfill \fi}
 \def\do##1{\catcode`##1=\other}\dospecials
 \catcode127=\other \catcode9=\other \catcode12=\other
 \parindent 0pt \parfillskip=0pt plus 1fil minus .8in
 \everypar{\hangindent 1in} \rightskip=0pt plus 2in
 \def\par{\ifvmode\penalty-50\medskip\else\endgraf\fi}
 \listingfont \obeylines \obeyspaces \global\pageno=1
 \input #1 {\eoffont(end of\/ file)}\endgraf\vfill\eject
 \ifright\null\vfill\eject\fi\endgroup}
{\obeyspaces\global\let =\ }
\catcode`\_=\other % allow _ in file names

\hsize=3truein
\vsize=7truein
\hoffset=-.5truein
\voffset=-.2truein
\newif\ifright \newif\ifmid
\newbox\lefthalf \newbox\midhalf
\output{\ifright
\shipout\hbox{\hbox to3.5in{\box\lefthalf\hss}%
   \hbox to3.5in{\box\midhalf\hss}%
   \vbox{\makeheadline\pagebody\makefootline}}
   \advancepageno\global\rightfalse
\else\ifmid\global\setbox\midhalf\vbox{\pagebody\makefootline}
   \global\midfalse\global\righttrue
\else\global\setbox\lefthalf\vbox{\makeheadline\pagebody\makefootline}
   \global\midtrue\fi\fi}

\special{landscape}

% A tab (^^I) prints as lowercase gamma.
% Character ^^M could be made visible, with a bit of work;
% at present, it's indistinguishable from newline (^^J).

% You can get up to 63 characters on a line without an overfull box.
% (But lines with more than 59 characters may overlap with the next column,
% or be clipped off in the rightmost column.)