<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">%% @texfile{
%%     filename   = "tugboat.sty",
%%     copyright  = "Copyright 1993,1999,2003,2006,2011-2024 TeX Users Group.
%%                   Unlimited copying and redistribution of this file
%%                   are permitted as long as this file is not
%%                   modified.  Modifications (and redistribution of
%%                   modified versions) are also permitted, but only if
%%                   the resulting file is renamed."
%%     version    = "see below \fileversion"
%%     date       = "see below \filedate",
%%     filetype   = "Plain TeX macros for TUGboat",
%%     requires   = "tugboat.cmn",
%%     supported  = "yes",
%%     email      = "TUGboat@tug.org",
%%     codetable  = "ISO/ASCII",
%%     keywords   = "tex users group, tugboat, plain tex",
%%     abstract   = "This file contains the plain-based macros
%%                   for preparation of items in TUGboat, the
%%                   Communications of the TeX Users Group.",
%%     }
%% $Id: tugboat.sty 607 2024-10-26 22:26:03Z karl $

\def\thistubstyle{plain}
\def\fileversion{v1.31}
\def\filedate{2024-10-26}

% general items

\def\makeatletter{\catcode`\@=11 }
\makeatletter           % used, as in PLAIN, in protected control sequences

%  stop reading this file if it's been loaded already
\ifx\tugstyloaded@\thistubstyle\makeatother\initializearticle
 \endinput\else\let\tugstyloaded@\thistubstyle\fi

\message{File `TUGBOAT.STY' \fileversion \space\space &lt;\filedate&gt;}

\input tugboat.cmn      % macros intended to be common to tugboat.sty and
                        % ltugboat.sty (latex style file)


%  some things with the same names as in, or reiterated from, AMS-TeX

\def\document{}                % override an AMS-TeX convention

\output{\output@}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  Directory.
%
%  **  fonts
%  **  page dimensions
%  **  headers/footers
%  **  page adjustment
%  **  output
%  **  general mechanism for tags
%  **  titles, authors, addresses
%  **  heads
%  **  text and subtext
%  **  lists
%  **  verbatim
%  **  figures
%  **  utilities
%  **  initialization

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  fonts  *****
%

%  Struts give ascenders and descenders to assist in baseline alignment
%  (e.g. of adjoining vertical boxes); useful only with text fonts.
%
%  \strut is defined in PLAIN .  The structure of \strutt is equivalent.

\newbox\struttbox
\def\strutt{\relax\ifmmode\copy\struttbox\else\unhcopy\struttbox\fi}

%  Struts are given the following dimensions for use in TUGboat:
%
%  \strut = height/depth of parenthesis in current font
%           (not the same as PLAIN)
%  \strutt height + depth = \normalbaselineskip,
%           height = same as \strut
%           (equivalent to PLAIN \strut )


%  The fonts below are sufficient for most ordinary TUGboat production.
%  Additional titling fonts are defined elsewhere, and occasionally an
%  extra font will be needed for a particular item (e.g. the device
%  charts) and defined in that file.

%  All PLAIN CM fonts.

\font\tenrm=cmr10
\font\ninerm=cmr9
\font\eightrm=cmr8
\font\sevenrm=cmr7
\font\sixrm=cmr6
\font\fiverm=cmr5

\font\teni=cmmi10 \skewchar\teni='177
\font\ninei=cmmi9 \skewchar\ninei='177
\font\eighti=cmmi8 \skewchar\eighti='177
\font\seveni=cmmi7 \skewchar\seveni='177
\font\sixi=cmmi6 \skewchar\sixi='177
\font\fivei=cmmi5 \skewchar\fivei='177

\font\tensy=cmsy10 \skewchar\tensy='60
\font\ninesy=cmsy9 \skewchar\ninesy='60
\font\eightsy=cmsy8 \skewchar\eightsy='60
\font\sevensy=cmsy7 \skewchar\sevensy='60
\font\sixsy=cmsy6 \skewchar\sixsy='60
\font\fivesy=cmsy5 \skewchar\fivesy='60

\font\tenex=cmex10

\font\tenbf=cmbx10
\font\ninebf=cmbx9
\font\eightbf=cmbx8
\font\sevenbf=cmbx7
\font\sixbf=cmbx6
\font\fivebf=cmbx5

\font\tentt=cmtt10
\font\ninett=cmtt9
\font\eighttt=cmtt8

\ifx\tubhyphenatett\@thisisundefined
  % do not hyphenate typewriter unless explicitly requested (as
  % tb0hyf.tex does).
  \hyphenchar\tentt=-1
  \hyphenchar\ninett=-1
  \hyphenchar\eighttt=-1
\fi

\font\tensl=cmsl10
\font\ninesl=cmsl9
\font\eightsl=cmsl8
\font\sevensl=cmti7             %  Would use cmsl7 if it were standard.
                                %  Currently needed only for \def of \LaTeX

\font\tenit=cmti10
\font\nineit=cmti9
\font\eightit=cmti8
\font\sevenit=cmti7

\font\tenuit=cmu10
\font\tenbfsl=cmbxsl10

\font\tensmc=cmcsc10
\font\ninesmc=cmcsc10           % redefine if cmcsc9 and/or cmcsc8 exist
\font\eightsmc=cmcsc10

\font\tentex=cmtex10            % for ASCII character set

\font\tenlogo=logo10
\font\ninelogo=logo9
\font\eightlogo=logo8
%
\font\tenlogosl=logosl10
\font\ninelogosl=logosl10 at 9pt
\font\eightlogosl=logosl10 at 8pt

\def\mit{\fam\@ne}              % from plain
\def\cal{\fam\tw@}              % from plain
\def\sy{\cal}

%  cmss fonts are not needed all the time.  Permit as-needed access.
\def\LoadSansFonts{%
  \global\font\twelvess=cmss10 scaled \magstep1
  \global\font\tenss=cmss10
  \global\font\niness=cmss9
  \global\font\eightss=cmss8
  \addto\tenpoint{\def\ssf{\tenss}}
  \addto\ninepoint{\def\ssf{\niness}}
  \addto\eightpoint{\def\ssf{\eightss}}
  \gdef\LoadSansFonts{}}

%  TUGboat section heads
\font \seventeenssb=cmssbx10 scaled \magstep3
\font \twelvessb=cmssbx10 scaled \magstep1

\newfam\sectitlefam
\textfont\sectitlefam=\seventeenssb \scriptfont\sectitlefam=\twelvessb

%  \stbaselineskip set in tugboat.com
\def\sectitlefont{%
  \fam\sectitlefam \seventeenssb \baselineskip=\stbaselineskip }

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  Definitions of \tenpoint, \ninepoint, etc.  *****
%

%  Following is a facility for adding commands to \tenpoint, \ninepoint
%  and \eightpoint.  \LoadSansFonts uses this technique above.
%  Also used to add math families, as with:
%       \addto\tenpoint{\textfont\frakfam...}
%  to add a Fraktur family.
%
\def\addto#1#2{%
  \csname @addsto\string#1\endcsname=
  \expandafter{\the\csname @addsto\string#1\endcsname#2}}
\def\@additionsto#1{\expandafter\the\csname @addsto\string#1\endcsname}
\expandafter\newtoks\csname @addsto\string\tenpoint\endcsname
\expandafter\newtoks\csname @addsto\string\ninepoint\endcsname
\expandafter\newtoks\csname @addsto\string\eightpoint\endcsname


\newskip\ttglue
\def\setttglue{%
  \edef\@thefont{\the\font}%  to restore this font after the setting
  \tt \ttglue=.5em plus .25em minus .15em
  \@thefont}

%  We assume that \scriptscriptfonts remain the same throughout
\scriptscriptfont\z@=\fiverm
\scriptscriptfont\@ne=\fivei
\scriptscriptfont\tw@=\fivesy
\scriptscriptfont\thr@@=\tenex
\scriptscriptfont\bffam=\sixbf

\newdimen\normaltenpointstretch    \normaltenpointstretch=1.6667pt
\def\NormalTenPointSpacing{\AdjustNormalSpacing\tenpoint{}}
\def\StretchyTenPointSpacing{\AdjustNormalSpacing\tenpoint{2.4}}

\def\tenpoint{%
  \normalbaselineskip=12pt
  \abovedisplayskip=3pt plus 3pt minus 1pt
  \belowdisplayskip=3pt plus 3pt minus 1pt
  \abovedisplayshortskip=0pt plus 3pt
  \belowdisplayshortskip=1pt plus 3pt minus 1pt
  \def\rm{\def\sl{\fam\slfam\tensl}\def\SMC{\ninerm}\fam\z@\tenrm}%
  \textfont\z@=\tenrm \scriptfont\z@=\sevenrm
  \def\oldstyle{\fam\@ne\teni}%
  \textfont\@ne=\teni \scriptfont\@ne=\seveni
  \textfont\tw@=\tensy \scriptfont\tw@=\sevensy
  \textfont\thr@@=\tenex \scriptfont\thr@@=\tenex
  \def\it{\def\SMC{\nineit}\fam\itfam\tenit}%
  \textfont\itfam=\tenit \scriptfont\itfam=\sevenit
  \def\sl{\def\SMC{\ninesl}\fam\slfam\tensl}%
  \textfont\slfam=\tensl \scriptfont\slfam=\sevensl
  \def\bf{\def\sl{\tenbfsl}\def\SMC{\ninebf}\fam\bffam\tenbf}%
  \textfont\bffam=\tenbf \scriptfont\bffam=\eightbf
  \def\smc{\tensmc}%
  \let\manual=\tenlogo
  \let\manualsl=\tenlogosl
  \def\tt{\tentt}\setttglue
  \def\upright{\tenuit}%
  \setbox\strutbox=\hbox{\vrule height7.5pt depth2.5pt width\z@}%
  \setbox\struttbox=\hbox{\vrule height8.5pt depth3.5pt width\z@}%
  \normalbaselines \rm
  \@additionsto\tenpoint}

\tenpoint                       % initialize -- default font


\newdimen\normalninepointstretch   \normalninepointstretch=1.5pt
\def\NormalNinePointSpacing{\AdjustNormalSpacing\ninepoint{}}
\def\StretchyNinePointSpacing{\AdjustNormalSpacing\ninepoint{2.4}}

\def\ninepoint{\normalbaselineskip=11pt
  \abovedisplayskip=2.5pt plus 2.5pt minus 1pt
  \belowdisplayskip=2.5pt plus 2.5pt minus 1pt
  \abovedisplayshortskip=0pt plus 2.5pt
  \belowdisplayshortskip=1pt plus 2.5pt minus 1pt
  \def\rm{\def\SMC{\eightrm}\fam\z@\ninerm}%
  \textfont\z@=\ninerm \scriptfont\z@=\sevenrm
  \def\oldstyle{\fam\@ne\ninei}%
  \textfont\@ne=\ninei \scriptfont\@ne=\seveni
  \textfont\tw@=\ninesy \scriptfont\tw@=\sevensy
  \def\it{\def\SMC{\eightit}\fam\itfam\nineit}%
  \textfont\itfam=\nineit
  \def\sl{\def\SMC{\eightsl}\fam\slfam\ninesl}%
  \textfont\slfam=\ninesl
  \def\bf{\def\SMC{\eightbf}\fam\bffam\ninebf}%
  \textfont\bffam=\ninebf \scriptfont\bffam=\sevenbf
  \def\smc{\ninesmc}%
  \let\manual\ninelogo
  \let\manualsl=\ninelogosl
  \def\tt{\ninett}\setttglue
  \setbox\strutbox=\hbox{\vrule height 6.75pt depth 2.25pt width\z@}%
  \setbox\struttbox=\hbox{\vrule height 7.75pt depth 3.25pt width\z@}%
  \normalbaselines \rm
  \@additionsto\ninepoint }

%  The following setting can be used when baselineskip = 10pt
%  \setbox\struttbox=\hbox{\vrule height 7.25pt depth 2.75pt width\z@}%


\newdimen\normaleightpointstretch  \normaleightpointstretch=1.333pt
\def\NormalEightPointSpacing{\AdjustNormalSpacing\eightpoint{}}
\def\StretchyEightPointSpacing{\AdjustNormalSpacing\eightpoint{2.25}}

\def\eightpoint{\normalbaselineskip=10pt
  \abovedisplayskip=2pt plus 2pt minus 1pt
  \belowdisplayskip=2pt plus 2pt minus 1pt
  \abovedisplayshortskip=0pt plus 2pt
  \belowdisplayshortskip=1pt plus 2pt minus 1pt
  \def\rm{\def\SMC{\sevenrm}\fam\z@\eightrm}%
  \textfont\z@=\eightrm \scriptfont\z@=\sixrm
  \def\oldstyle{\fam\@ne\eighti}%
  \textfont\@ne=\eighti \scriptfont\@ne=\sixi
  \textfont\tw@=\eightsy \scriptfont\tw@=\sixsy
% \textfont\thr@@=\eightex \scriptfont\thr@@=\eightex
  \def\it{\def\SMC{\sevenit}\fam\itfam\eightit}%
  \textfont\itfam=\eightit
  \def\sl{\def\SMC{\sevensl}\fam\slfam\eightsl}%
  \textfont\slfam=\eightsl
  \def\bf{\def\SMC{\sevenbf}\fam\bffam\eightbf}%
  \textfont\bffam=\eightbf \scriptfont\bffam=\sixbf
  \def\smc{\eightsmc}%
  \let\manual\eightlogo
  \let\manualsl\eightlogosl
  \def\tt{\eighttt}\setttglue
  \setbox\strutbox=\hbox{\vrule height 6pt depth 2pt width\z@}%
  \setbox\struttbox=\hbox{\vrule height 7pt depth 3pt width\z@}%
  \normalbaselines \rm
  \@additionsto\eightpoint }

%  The 8pt cap/small cap font is not loaded.  See a corresponding remark
%  above for the 9pt csc font.

%  this is equivalent to baselineskip = 9pt
%  \setbox\struttbox=\hbox{\vrule height 6.5pt depth 2.5pt width\z@}%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%  Following will allow text to be a bit stretchier than the built-in
%  setting; TeXbook, page 433, 355

\def\@setstretch{\fontdimen3\the\font=}
\def\AdjustNormalSpacing#1#2{%  #1=pointsize, #2=adjustment factor
  {\T@stDimen=#2\csname normal\expandafter\gobble\string#1stretch\endcsname
  #1%
  \rm\@setstretch\T@stDimen
  \it\@setstretch\T@stDimen
  \bf\@setstretch\T@stDimen
  }}

% ring accent, which plain.tex defines no macro for.  \r is the LaTeX name.
\def\r#1{\accent"17 #1}

%  Anticipated changes to this font handling scheme:
%
%  Dynamic loading of fonts, probably in groups according to size
%  Removal of \rm, \bf, etc., from \*point expansions, replacement
%    by generic \rm, \bf, etc. definitions
%  Mechanism for switching neatly between serif and sans-serif

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  page dimensions  *****
%

%  vertical dimensions

\newdimen\trimlgt       \trimlgt=11in           % 10.5in (vols 7-9)
\newdimen\headmargin    \headmargin=3.5pc       % 2.5pc  (vols 7-9)
\newdimen\pagelgt
\newdimen\rheadlgt      \rheadlgt=2.5pc         % + headmargin = 6pc = 1in
\newdimen\toplgt        \toplgt=\z@
\newdimen\normalcollgt  \normalcollgt=54pc      % 52pc for 5#2
\newdimen\collgt        \collgt=\normalcollgt
\newdimen\Collgt
\maxdepth=2pt
\newdimen\botlgt        \botlgt=\z@
\newdimen\rfootlgt      \rfootlgt=2pc

\newif\ifThisIsFirstPage        \ThisIsFirstPagefalse

\def\resetpagelgt{%
  \pagelgt=\collgt \Collgt=\collgt
  \advance\pagelgt by \rheadlgt
  \ifThisIsFirstPage \advance\Collgt by-\toplgt
                     \advance\Collgt by-\botlgt \fi
  \advance\pagelgt by \maxdepth
  \global\advance\pagelgt by \rfootlgt
  \global\vsize=\Collgt }

\def\resetfpagelgt{%
  \global\ThisIsFirstPagetrue
  \resetpagelgt }                 % exclude special first page material

\resetpagelgt
\raggedbottom

%  horizontal dimensions

\newdimen\colwd
\newdimen\intercolwd    \intercolwd=\z@
\newdimen\pagewd        \pagewd=39pc
\newdimen\trimwd        \trimwd=\pagewd
\newdimen\oddleftindent \oddleftindent\z@
\newdimen\evenleftindent \evenleftindent\z@

\def\onecol{\colwd=\pagewd            \OneCol }

\newdimen\onenarrowcolwd        \onenarrowcolwd=30pc
\def\onenarrow{\colwd=\onenarrowcolwd \OneCol }

%       before 5#2, `narrow' was 34pc
\newdimen\onemediumcolwd        \onemediumcolwd=34pc
\def\onemedium{\colwd=\onemediumcolwd  \OneCol }

\newdimen\twocolcolwd           \twocolcolwd=18.75pc
\def\twocol{\colwd=\twocolcolwd \intercolwd=1.5pc \TwoCol }

\newdimen\threecolcolwd         \threecolcolwd=12pc
\def\threecol{\colwd=\threecolcolwd \intercolwd=1.5pc \ThreeCol }

\def\CenterOneCol{%
  \oddleftindent\pagewd
  \advance\oddleftindent -\colwd
  \divide\oddleftindent\tw@
  \evenleftindent\oddleftindent
  \coloffset\ifodd\pageno\oddleftindent\else\evenleftindent\fi
  }

\def\OneCol{\hsize=\colwd \CenterOneCol \numcols=1 \resetmaxcols}
\def\ZeroLeftIndents{\oddleftindent\z@ \evenleftindent\z@ \coloffset\z@ }
\def\TwoCol{\hsize=\colwd \numcols=2 \resetmaxcols \ZeroLeftIndents}
\def\ThreeCol{\hsize=\colwd \numcols=3 \resetmaxcols \ZeroLeftIndents}

\def\resetmaxcols{%
  \ifnum\numcols&gt;\maxcols
    \ifOverlaysinTeX \maxcols=\numcols
    \else \immediate\write\sixt@@n{%
      The new setting of \string\numcols is greater than \string\maxcols.^^J
      Either allow overlays in TeX or increase \string\maxcols.}\fi
  \fi}

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  headers/footers  *****
%

\def\pagenoprefix{}

\def\rtitlex{\def\tubfont{\tenpoint\rm}\TUB, \volx }
\def\rtitle{%
  \hbox to \pagewd{%
    \tenrm
    \makestrut[10pt;\z@]%
    \ifodd\pageno \rtitlex\qquad\midrtitle\hfil\pagenoprefix\number\pageno
    \else \pagenoprefix\number\pageno\hfil\midrtitle\qquad\rtitlex \fi
    }%
  }

\def\runhead{\vbox to \rheadlgt{\rtitle \vfil }}

\def\rfoot{%
  \hbox to \pagewd{%
    \tenpoint \frenchspacing
    \def\\{\unskip\ \ignorespaces}% line break commands produce normal space
    \let\newline=\\%
    \tubtypesetdoi
    \makestrut[\z@;0.5pc]%
    \ifPrelimDraft
      \midrtitle\hfil\midrtitle
    \else
      \ifodd\pageno
        \hfil\thetitle
      \else
        \footauthors\hfil
      \fi
    \fi
    }%
  }

\def\footauthors{%
  \bgroup
    \count1=1
    \authorloop
  \egroup}

\def\authorloop{%
  \ifnum\count1&gt;1
    \ifnum\count1&lt;\authornumber
      ,      % Wanted space.
    \else
      ,      % Idem. Was "{} and", but we prefer all commas now.
    \fi
  \fi
  \theauthor{\the\count1}%
  \ifnum\count1&lt;\authornumber
    \advance\count1 by 1
    \authorloop
  \fi}

\def\runfoot{\vbox to \rfootlgt{\vfil \rfoot }}

% DOI output. See tugboat.dtx for comments.
%
% Macros so we can use the same code as tugboat.dtx.
\newif\iftubomitdoioption  % explicit option when posting early

\newif\iftubsecondcolstart % when we splice, e.g., tb139wermuth-isdim
\newdimen\tubcolwidthandgutter
\newif\iftubfinaloption    % set in tugboat.dates
\def\scriptsize{\let\rm=\sevenrm \font\tt=cmtt8 at 7pt % fake 7pt match LaTeX
                \baselineskip=8pt \relax} % fake
\def\@empty{}
%
\def\tubdoiprefix{10.47397/tb} % the number crossref assigned us
%
\def\tubtypesetdoi{\iftubomitdoioption\else % if not explicit omission ...
 \ifnum\authornumber&gt;0 % our convention: no doi if no author
 \iftubfinaloption % do this if [final], even if pageno&gt;900
  \vbox to 0pt{% don't impact normal layout
    \scriptsize
    \edef\thedoi{\ifnum\count0&gt;900 xnot\fi % but make url invalid if &gt;900
                \tbsurl{doi.org/\tubdoiprefix/\tbissident/\jobname}}%
    \vskip\baselineskip
    \iftubsecondcolstart \moveright\tubcolwidthandgutter \fi
    \rlap{\expandafter\tbsurl\expandafter{\thedoi}}%
    \vss
  }%
  \global\let\tubtypesetdoi\@empty % only do it once, no matter what.
 \fi
 \fi
\fi}

%  Macros to produce extra running heads for stripping onto pages
%  received as camera copy.  Format must be preset to \OneCol, and
%  start on a new page.

%  Generate 5 (4 + normal running head) per page.

\def\DrawT@pLines{%
  \vskip\topskip
  \ulap{%
    \line{%
      \raise 1ex\rlap{\leaders\hrule\hskip\pagewd}%
      \leaders\hrule\hfill
      }}
  \medskip}

\def\r@nhead{%
  \vbox to .23\vsize{%
    \basezero \hsize=\pagewd \vfil
    \topregister \vskip\headmargin \runhead \DrawT@pLines }
  \medskip
  \advancepageno }

\def\nextrunner{%
  \ifnum\T@stCount&gt;0
    \ifnum\T@stCount&gt;5 \TestCount=5 \else\TestCount=\T@stCount \fi
    \advance\T@stCount by-\TestCount
    \DrawT@pLines           % always one at top of page
    \loop\ifnum\TestCount&gt;1 \r@nhead \advance\TestCount by\m@ne \repeat
    \newpage
    \def\@next{\nextrunner}%
  \else \def\@next{}%
  \fi
  \@next }

%  Use \ExtraRunheads to generate running heads for stripping (e.g. for
%  author-supplied camera-ready copy).  E.g., ``\ExtraRunheads 12, {}.'' will
%  generate 12 TUGboat running heads, up to 5 per page, starting with
%  the current page number.

\def\ExtraRunheads #1, #2.{%
  \T@stCount=#1
  \gdef\pageprefix{#2}%   % as in A-10 for appendices; not used just now
  \nextrunner }

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  insertions  *****
%

\newif\if@floatable     \@floatabletrue         % sometimes we don't want
\def\nofloat{\@floatablefalse}                  % midinsertions to float

% redefine \@ins to avoid the \par of PLAIN
\def\@ins{\begingroup\setbox\z@\vbox\bgroup}

\newinsert\botins
\newif\ifp@ge \newif\if@mid \newif\if@bot
\def\topinsert{\@midfalse\p@gefalse\@botfalse\@ins}
\def\botinsert{\@midfalse\p@gefalse\@bottrue\@ins}
\def\midinsert{\@midtrue\@botfalse\@ins}
\def\pageinsert{\@midfalse\@botfalse\p@getrue\@ins}
\skip\botins=\z@skip
\count\botins=1000
\dimen\botins=\maxdimen
\def\endinsert{\egroup % finish the \vbox
  \gdef\@next{}%
  \if@mid \dimen@\ht\z@ \advance\dimen@\dp\z@
    \advance\dimen@12\p@ \advance\dimen@\pagetotal
    \if@floatable
      \ifdim\dimen@&gt;\pagegoal\@midfalse\@botfalse\p@gefalse\fi\fi
  \fi
  \if@mid
    \vskip\abovedisplayskip
    \box\z@
    \vskip\belowdisplayskip
    \gdef\@next{\@asifbelowdisplay}%
  \else\insert\if@bot\botins\else\topins\fi
   {\penalty100 % floating insertion
    \if@bot\medskip\nobreak\fi
    \splittopskip\z@skip
    \splitmaxdepth\maxdimen \floatingpenalty\z@
    \ifp@ge \dimen@\dp\z@
      \vbox to\vsize{\unvbox\z@\kern-\dimen@}% depth is zero
    \else \box\z@\fi
    \if@bot\else\medskip\fi
   }%
  \fi\endgroup\@next}

%  Footnotes are mainly supported by PLAIN format, with these
%  exceptions.

\skip\footins=10pt
\def\footnoterule{\kern-5pt
        \hrule width 5pc \kern 4.6pt } % the \hrule is .4pt high

\newif\ifDelayFirstPar          \DelayFirstParfalse
\def\vfootnote#1{\ifFirstPar \DelayFirstPartrue \fi
  \insert\footins\bgroup
  \interlinepenalty\interfootnotelinepenalty
  \splittopskip\ht\strutbox % top baseline for broken footnotes
  \splitmaxdepth\dp\strutbox \floatingpenalty\@MM
  \leftskip\z@skip \rightskip\z@skip \spaceskip\z@skip \xspaceskip\z@skip
  \rm \parindent=\normalparindent % always indent footnotes; added for TUGboat
  \TUBstartfootnotehook
  \textindent{#1}\makestrut[10pt;\z@]\futurelet\next\fo@t}
\def\@foot{\strut\egroup\TUBendfootnotehook
        \ifDelayFirstPar \SetupFirstPar \global\DelayFirstParfalse \fi }
\newif\ifFirstPar       \FirstParfalse
\def\SetupFirstPar{\global\parindent=\z@ \global\FirstPartrue }

\def\TUBstartfootnotehook{}
\def\TUBendfootnotehook{}

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  output  *****
%

%       Reorganize \pagecontents from PLAIN to put footnotes at very
%       bottom of page, even if \raggedbottom.  Also add bottom insertions.

\def\pagecontents{%
  \ifvoid\topins\else\unvbox\topins\fi
  \dimen@=\dp\@cclv \unvbox\@cclv % open up \box255
  \ifr@ggedbottom \kern-\dimen@ \vfil \fi
  \ifvoid\footins\else % footnote info is present
    \vskip\skip\footins
    \footnoterule
    \unvbox\footins\fi
  \ifvoid\botins\else
    \vskip\skip\botins
    \unvbox\botins\fi }


%  Trim (registration) marks may or may not be placed around the pages;
%  Overlaying may or may not be done within TeX (as opposed
%  to the device driver).

\newif\ifTrimmarks              \Trimmarksfalse
\newif\ifOverlaysinTeX          \OverlaysinTeXtrue


%  All columns containing data are formatted by \midpage.  Trim marks
%  are put on all columns, but running heads only on the last column
%  (i.e. column number = \numcols)

\def\midpage#1{%
  \vbox{
    \basezero
    \hrule height\z@ depth\z@ width\p@
    \ifTrimmarks
      \vskip-1in                % default offset for laser printers
                                % this puts top trim at edge of paper
      \vbox to \trimlgt \bgroup
      \topregister
      \vskip \headmargin
    \else
      \vskip-\rheadlgt           % this puts runhead above default offset
    \fi
    \vbox to \pagelgt{
      \ifnum\xcol=\numcols \runhead \else \vbox to \rheadlgt{}\fi
      \ifThisIsFirstPage \firsthead \fi
      \hbox to \pagewd{#1}       % \vsize applied in \pagebody
      \ifThisIsFirstPage \firstfoot \fi
      \vfil                      % if no depth, avoid underfull box
      \ifnum\xcol=\numcols \runfoot \else \vbox to \rfootlgt{}\fi
      }
    \ifTrimmarks \vfill \botregister \egroup \fi
    }}

%  The production version includes trim marks, which are required
%  on photographic paper, but are unsuitable for laser printer output
%  (because they land at the edges of the page).  For multiple
%  column output, allowance is made for column overlays either
%  within TeX or by the driver.  The default is to have all
%  overlays done within TeX, but large pages or matters of efficiency
%  may dictate that driver-overlay is more appropriate.

%  When the overlaying is done within TeX, the .dvi contains just
%  one page for each page to be printed.  However, in the case
%  that a driver is to do the overlaying we must anticipate that
%  it will not be smart enough to properly overlay different numbers
%  of .dvi pages for different printed pages (e.g. in the case that
%  one job has both single- and double-column layout).  Thus, for
%  each printed page, TeX constructs a constant number (=\maxcols)
%  of .dvi pages.  Columns 1 through and including \numcols will
%  be usual .dvi pages containing information for the typeset columns.
%  Upon reaching column number \numcols, TeX will `fill out' the
%  printed page with empty columns to \maxcols.


%  set up auxiliary `page numbers'
%  \pageno = \count0  as used in PLAIN

%  \xcol is the column number within a page; ranges from 1 to \maxcols
\countdef\xcol=1        \xcol=1

%  \spoolno is the ordinal number of `.dvi' pages (i.e. the number
%  of \shipouts performed)
\countdef\spoolno=2     \spoolno=0

\def\newcol{\endgraf\vfill\eject}

\def\newpage{%
  \vfill\eject
  \loop
  \ifnum\xcol&gt;1
    {\leavevmode\endgraf\vfill\eject} % \xcol is advanced in the output routine
  \repeat
  }

\newcount\numcols               % `real' number of columns

\newcount\@maxcolsofar          % internal counter for box allocation
\@maxcolsofar=0

\newcount\maxcols               % job-wide maximum number of columns
\maxcols=2


                                % save the column or ship it out
\def\@saveorship{%
  \ifOverlaysinTeX
    \ifnum\xcol&gt;\@maxcolsofar   % if we need another column box allocated
      \global\advance\@maxcolsofar\@ne
      \newboxcs{column\number\xcol}%
    \fi
    \global\setboxcs{column\number\xcol}%
  \else
    \global\advance\spoolno\@ne
    \shipout
  \fi
  }

%  horizontal offset of column from left edge of page
\newdimen\coloffset             \coloffset\z@
\def\incrcoloffset{%
  \global\advance\coloffset\colwd
  \global\advance\coloffset\intercolwd
  }

\def\output@{%
  \@saveorship\midpage{\kern\coloffset\pagebody\hfil}
  \incrcoloffset
  \ifnum\xcol=\numcols   % if at `real' last column, fill out page with
    \loop                % empty columns
    \ifnum\xcol&lt;\maxcols
      \global\advance\xcol\@ne
      \@saveorship\midpage{\vbox to \collgt{}\hfil}
    \repeat
  \fi
  \ifnum\xcol=\maxcols   % put page together if TeX is overlaying
    \ifOverlaysinTeX
      \global\advance\spoolno\@ne
      \shipout\hbox{%
        \xcol=1
        \loop \rlap{\boxcs{column\number\xcol}}%
        \ifnum\xcol&lt;\maxcols
          \global\advance\xcol\@ne
        \repeat
        \hbox to \pagewd{}%
        }%
    \fi
    \D@EndPage          % possible shortening of next page
    \global\coloffset\ifodd\pageno\oddleftindent\else\evenleftindent\fi
    \global\xcol=1
  \else
    \global\advance\xcol\@ne
  \fi
  \ExecuteNextDC         % possible `Delayed Command'
  }

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  page adjustment  *****
%

%  In the absence of automatic column-balancing, provide a mechanism
%  for manually shortening a specified page.

\newif\ifSh@rtPage              \Sh@rtPagefalse
\newif\ifSh@rtPagePending       \Sh@rtPagePendingfalse
\newcount\Sh@rtPageNo
\newdimen\Sh@rtPageLgt

\def\@to{to}                    \def\@by{by}
%       #1 = to/by; #2 = \dimen; #3 = &lt;dimen&gt;; #4 = * of Shorten*Page
\def\@toby#1#2#3#4{%
  \def\@tb{#1}%
  \ifx \@tb\@to \global #2=#3
  \else \ifx \@tb\@by \T@stDimen=#3         % accommodate negative #3
             #2=\normalcollgt \global\advance #2 by -\T@stDimen
        \else \errmessage{#1 is invalid syntax; \string\Shorten#4Page
                          requires "to" or "by"}\fi
  \fi }

\def\@plusno#1#2;{%
  \if +#1\T@stCount=\pageno \advance\T@stCount by #2
  \else \T@stCount=#1#2 \fi }

\def\ShortenPage #1 #2 #3. {%
  \global\Sh@rtPagePendingtrue
  \@plusno#1;\global\Sh@rtPageNo=\T@stCount
  \@toby{#2}{\Sh@rtPageLgt}{#3}{}}
\def\ShortenThisPage #1 #2. {%
  \global\Sh@rtPagetrue
  \@toby{#1}{\vsize}{#2}{This}}

%  Two cases: 0 = last page was nonstandard; reset \vsize
%             1 = do not reset \vsize: okay or length already reset
\def\D@EndPage{%
  \advancepageno
  \T@stCount=1
  \ifThisIsFirstPage \T@stCount=0 \global\ThisIsFirstPagefalse
                     \resetfirsthead \resetfirstfoot
                     \global\collgt=\normalcollgt \fi
  \ifSh@rtPage \T@stCount=0 \global\Sh@rtPagefalse \fi
  \ifSh@rtPagePending
    \ifnum\pageno = \Sh@rtPageNo \T@stCount=1
      \global\vsize=\Sh@rtPageLgt
      \global\Sh@rtPagePendingfalse
      \global\Sh@rtPagetrue \fi
  \fi
  \ifcase \T@stCount \resetpagelgt \fi }

%  Add more powerful means of adjusting pages by keeping a list of
%  commands to be executed prior to making up the next page.  This
%  technique will be expanded in the next version of the output
%  routine.

%  "\DelayedCommand &lt;page number&gt; &lt;column number&gt; &lt;command&gt;\endCommand"
%  places the token list &lt;command&gt; at the end of a list of "things to do".
%  At the end of every column, the output routine checks this list to
%  see whether the head of the list should be "executed" prior to
%  building the next column.  If so, the execution is performed.
%  Right now, items must be placed in the execution list in order,
%  and all items for a given column must be combined into a single
%  token list.

%  Natural applications are double column figures and column size
%  adjustments.  E.g.
%  \DelayedCommand +5 1 \global\advance\vsize by 2\baselineskip\endCommand
%  will increase the \vsize of the first column of the page 5 pages from
%  "now" by 2 baselines.  To pull the \vsize back to normal would require
%  another use of \DelayedCommand.  Double column figures can be achieved
%  with insertions called by \DelayedCommand.

%  Right now the technique is messy, but it can be used by those who know
%  how it's implemented and know its limitations.

\newtoks\@DelayedCommandList

\def\DelayedCommand #1 #2 #3\endCommand{%
  \@plusno#1;%
  \edef\@temp{\the\@DelayedCommandList&lt;\number\T@stCount&gt;}%
  \global\@DelayedCommandList=\expandafter{\@temp&lt;#2&gt;#3\endCommand}%
  }

\def\@FindNextDCPoint &lt;#1&gt;&lt;#2&gt;#3\endList{%
  \def\DCpage{#1}\def\DCcolumn{#2}}

\def\FindNextDCPoint{%
  \edef\@temp{\the\@DelayedCommandList}%
  \ifx\@temp\empty \def\DCpage{\@M}\def\DCcolumn{0}%
  \else
    \edef\@form{%
      \noexpand\@FindNextDCPoint\the\@DelayedCommandList\noexpand\endList}%
    \@form
  \fi}

\def\@ExecuteNextDC &lt;#1&gt;&lt;#2&gt;#3\endCommand#4\endList{%
  \global\@DelayedCommandList={#4}%
  #3}

\def\ExecuteNextDC{%
  \FindNextDCPoint
  \ifnum \pageno=\DCpage \ifnum\xcol=\DCcolumn
    \edef\@form{%
      \noexpand\@ExecuteNextDC\the\@DelayedCommandList\noexpand\endList}%
    \@form
  \fi \fi}

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  general mechanism for tags  *****
%

%  Upon sensing an opening tag (call it `\foo' here), the following process
%  is set in motion:
%    1. \begingroup (so definitions and settings are localized);
%    2. the default situation for \foo is set up;
%    3. if appropriate, an \everyfoo list is read (this allows one
%       to override the TUGboat.sty factory defaults);
%    4. optional commands are read.  This involves looking ahead for
%       a `[' and `normalizing' the optional environment so that
%       backslashes and braces are interpreted as their standard selves.
%       After the options are read, the `\',`{', and `}' are restored
%       to their status appropriate to \foo;
%    5. the \@beginfoo macro is executed.  This
%       may involve branching dependent upon flags set by options.  It may
%       also be a place where spaces and carriage-returns are activated.
%    6. the `argument' to \foo is read and stored or processed on
%       the fly (the method employed is generally fixed for each tag).
%       The argument may be delimited by *...* (called the `short-form'
%       here), or up to ...\endfoo (called the `long-form').
%    7. a cleanup macro is executed which also ends the current group.
%       This may do all the work if an argument has been read and stored.

%  Checking ahead.
%  Often we check ahead to determine the next course of action.
%  \@checknexttoken is used to check for optional commands, to check for the
%  short-form argument-delimiter, and to ignore characters in certain
%  situations.  The macro is just a check; applications must do whatever
%  is appropriate with the ensuing token.

%  \@checknexttoken checks the next token against argument #1.  If the
%  two are the same, #2 is executed, otherwise #3.  The comparison is
%  done with \ifx.  Since we check ahead with \futurelet, the first
%  argument is stored with \let as well.  To include the case
%  where #1 may be a space, we have to go through a small contortion
%  to \let\@basetoken= that space.

%  At times, the \@nexttoken will be \outer and this will prevent its
%  being incorporated in the definition of \@next below.  For this reason,
%  we store `\ifx\@basetoken\@nexttoken' away in a definition at a time
%  when \@nexttoken is undefined and won't cause a problem.

\def\if@baseis@next{\ifx\@basetoken\@nexttoken}

\long\def\@checknexttoken #1#2#3{%
  \futurelet\@basetoken\iffalse#1\fi
  \long\def\@next{%
%    \ifx \@basetoken\@nexttoken
    \if@baseis@next
      \long\def\@@next{#2}%
    \else\long\def\@@next{#3}\fi
    \@@next}%
  \futurelet\@nexttoken\@next}

%  Eliminating characters from input.
%  The following macros check ahead to see whether the next token is a
%  token to be parsed from the input stream.  \@ignoreall keeps
%  checking to eliminate all such characters, whereas \@ignoreone drops
%  at most one.  Argument #2 is executed after characters are eliminated.

%  The token is removed by defining a control sequence whose
%  contextual form includes the token.

        % execute #2 after ignoring (possibly) one occurrence of #1
\long\def\@ignoreone#1#2{%
  \def\@ignoreform#1{#2}%
  \@checknexttoken{#1}{\@ignoreform}{#2}%
  }

        % execute #2 after ignoring all occurrences of #1
\long\def\@ignoreall#1#2{%
  \def\@ignoreform#1{\@ignoretest}%
  \def\@ignoretest{\@checknexttoken{#1}{\@ignoreform}{#2}}%
  \@ignoretest
  }

%  Particularly useful ignorances.

        % execute #1 after ignoring spaces
\def\DeleteOptionalSpaces#1{%
  \@ignoreall{ }{#1}%
  }
        % execute #1 after ignoring spaces and \pars
\def\DeleteOptionalSpacesandPars#1{%
  \@ignoreall{ }{\@ignoreall{\par}{#1}}%
  }


%  Checking and reading options.
%  To check for the next optional argument, the macros must look
%  ahead to the next character.  If the next character is a `[',
%  the option-reading mechanism is invoked.  This check may be suppressed if
%  the user has executed the \lastoption option.  If \@lastoption is
%  "true" or if the [ is NOT next, the macro goes on to reading any
%  arguments and executing appropriately.

\def\@checkoptions{%
  \if@lastoption
    \def\@next{\@executetoend}%
  \else
    \def\@next{\@checknexttoken {[}{\@readoptions}{\@executetoend}}%
  \fi
  \@next
  }

%  Default "options" on start-up.  Unless over-ridden, the situation
%  will be:
%    1. there may be another option to check (i.e. \@lastoptionfalse);
%    2. it will be necessary to read the input file to determine the
%       method of marking arguments (i.e. \@longformfalse);
%    3. arguments will be handled on the fly (i.e. \@savingargumentfalse);
%    4. the long-form ending delimiter will be \end... (where ... is
%       the tag with which we're currently operating.

\newif\if@lastoption            \@lastoptionfalse
\def\lastoption{\@lastoptiontrue}

\newif\if@longform              \@longformfalse
\def\longform{\@longformtrue}

\newif\if@savingargument        \@savingargumentfalse

\newtoks\enddelim

\def\@defaultoptions{%
  \@lastoptionfalse
  \@longformfalse
  \@savingargumentfalse
  \enddelim=\expandafter{\csname end\CurrentTag\endcsname}%
  \let\@long\empty
  }

%  To read an optional command, \catcodes of \ { } are restored to their plain
%  values, and the [...] form is parsed out by \@@readoptions.  The argument
%  to \@@readoptions is then executed, the 3 specials are restored and
%  the we check again for [ after deleting spaces.  One might, alternatively,
%  parse out the initial `[' and activate the `]' to end options, but
%  this would make it awkward to place options within other macros (since
%  the `]' would have to be \catcoded properly for the definition).

\def\@readoptions{%
  \savecat\\\makeescape\\%
  \savecat\{\makebgroup\{%
  \savecat\}\makeegroup\}%
  \@@readoptions}

\def\@@readoptions[#1]{%
  #1%
  \restorecat\\\restorecat\{\restorecat\}%
  \DeleteOptionalSpaces{\@checkoptions}%
  }


%  Short Form Tagging.
%  We specify a character (*) to be used as a begin/end delimiter
%  for the argument to most tags.  This code could be copied and
%  altered a bit to use another character.

%  The character will be encountered as either type `other' or as
%  an `active' character.

\newtoks\@otherSFD
\@otherSFD={*}
\let\@SFD=*                     % used in \@checknexttoken

\newtoks\@activeSFD
{\makeactive\*
  \global\@activeSFD={*}%
}

\let\@plainast=\ast
\def\ast{\ifmmode\@plainast\else *\fi}


%  Reading to the end-tag.
%  Macros may just do their business after options have been
%  read.  In this case, there is no end-tag to worry about.
%  Otherwise, the macros either read to the "long-form" of end-tag
%  (e.g. \endtitle or \endauthor) or to the short-form (assumed to
%  be * here).  Unless an option has specified
%  that the long-form is to be used, the macros look ahead to
%  see whether the short-form delimiter occurs next.  If so,
%  it is assumed that the short-form is being used.  In any case,
%  the appropriate \@begin... macro is executed before the argument is
%  handled.

\newcount\@numarguments         \@numarguments=1

\def\@executetoend{%
  \ifnum\@numarguments&gt;0
    \if@longform \def\@afterbegintag{\@longparse}%
    \else
      \def\@afterbegintag{\@checknexttoken
                  {\@SFD}{\@shortparse}{\@longparse}}%
    \fi
  \else
    \def\@afterbegintag{}%
  \fi
  \csname @begin\CurrentTag\endcsname
  \@afterbegintag
  }

%  If the short-form is being used and an argument is to be saved,
%  we must define a "form" which TeX may follow to pull out the
%  tag's argument.  The argument is stored away in the token register
%  \@argument, and the appropriate end-operation is performed.
%  Otherwise (the `argument' is processed on-the-fly), we parse out
%  the initial short-form delimiter and activate the ending one.

\newtoks\@argument

\def\@shortparse{%
  \if@savingargument
    \edef\@form{%
      \def\noexpand\@@shortparse\the\@otherSFD####1\the\@otherSFD}%
    \@long\@form{\@argument{##1}\csname end\CurrentTag\endcsname}%
  \else
    \expandafter\makeactive\csname\the\@otherSFD\endcsname
    \expandafter\def\the\@activeSFD
      {\csname end\CurrentTag\endcsname
       \expandafter\makeother\csname\the\@otherSFD\endcsname}%
    \def\@@shortparse{%
      \expandafter\@ignoreone\expandafter{\the\@otherSFD}%
        {}%
      }%
  \fi
  \@@shortparse}

%  On the other hand, if the long form is used, TeX must parse to
%  the long-form ending tag.  Ordinarily we know the ending-tag
%  because it is just the \end... which corresponds to the tag
%  which initiated the process.  We do allow for the possibility,
%  however, that we may want to switch this for some reason. E.g.
%  the different \verbatim styles allow for \verbatim...\endverbatim
%  and ||...||.  The easiest way to implement the || style is
%  to have the first || call \verbatim and have \verbatim know
%  to look for || as the end-tag instead of \endverbatim.  This may
%  be accomplished by allowing for the possibility of different
%  end-tags as below.

\def\@longparse{%
  \if@savingargument
    \edef\@form{\def\noexpand\@@longparse####1\the\enddelim}%
    \@long\@form{\@argument{##1}\csname end\CurrentTag\endcsname}%
  \else \def\@@longparse{}\fi
  \@@longparse
  }

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%  Macros generally available to tags.

\def\longargument{\def\@long{\long}}

\def\@authorstyle{\@@@a}
\def\@inlinestyle{\@@@i}
\def\@displaystyle{\@@@d}
\def\@altinlinestyle{}
\def\@altdisplaystyle{}

\newif\if@removeprewhite        \@removeprewhitefalse
\newif\if@removepostwhite       \@removepostwhitefalse
\def\removeprewhite{\@removeprewhitetrue}
\def\removepostwhite{\@removepostwhitetrue}

%  Allow for line numbers on a listing as well as rules above and below.
\newif\if@ruled         \@ruledfalse
\newif\if@numbered      \@numberedfalse
\newcount\linenumber
\newcount\globallinenumber      \globallinenumber = 0
\newif\if@continuingnumbers \@continuingnumbersfalse
\def\continuenumbers{\numbered\@continuingnumberstrue}

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  title, section title, authors, addresses  *****
%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  title

\def\title{%
  \begingroup
  \def\CurrentTag{title}%
  \@defaultoptions
  \@savingargumenttrue
  \@checkoptions}

\def\endtitle{%
  \global\toks@=\expandafter{\the\@argument}%
  \endgroup
  \edef\thetitle{\ignorespaces\the\toks@\unskip}%
  }

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  section titles

%  Material mostly in tugboat.com now

\setbox\T@stBox=\hbox{\sectitlefont O}
\newdimen\stfontheight          \stfontheight=\ht\T@stBox

\def\sectitle{%
  \begingroup
  \def\CurrentTag{sectitle}%
  \@defaultoptions
  \@savingargumenttrue
  \global\SecTitletrue
  \@checkoptions}

\def\endsectitle{%
  \@sectitle{\the\@argument}%
  \endgroup
  }

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  authors

\newcount\authornumber

\def\author{%
  \begingroup
  \def\CurrentTag{author}%
  \global\advance\authornumber by 1
  \@defaultoptions
  \@savingargumenttrue
  \@checkoptions}

\def\endauthor{%
  \global\toks@=\expandafter{\the\@argument}%
  \endgroup
  \expandafter\edef\csname theauthor\number\authornumber\endcsname
      {\ignorespaces\the\toks@\unskip}%
  \expandafter\let\csname theaddress\number\authornumber\endcsname\relax
  \expandafter\let\csname thenetaddress\number\authornumber\endcsname\relax
  }

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  addresses

\newif\if@address \@addressfalse
\def\address{%
  \@addresstrue
  \begingroup
  \def\CurrentTag{address}%
  \@defaultoptions
  \@savingargumenttrue
  \let\@addressstyle=\@authorstyle
  \def\inline{\let\@addressstyle=\@inlinestyle}%
  \def\display{\let\@addressstyle=\@displaystyle}%
  \@checkoptions}

\def\endaddress{%
  \ifx\@addressstyle\@inlinestyle
    \def\\{, }\the\@argument
    \endgroup
    \def\@next{}%
  \else\ifx\@addressstyle\@displaystyle
    \endgraf\raggedright
    \everypar={\hangindent 1.5\parindent}%
    \def\\{\endgraf}%
    \def\|{\unskip\hfil\break}%
    \vskip\abovedisplayskip
    \the\@argument\endgraf
    \vskip\belowdisplayskip
    \@asifbelowdisplay
    \endgroup
    \def\@next{\ignorespaces}%
  \else
    \global\toks@=\expandafter{\the\@argument}%
    \endgroup
    \expandafter\edef\csname theaddress\number\authornumber\endcsname
      {\ignorespaces\the\toks@\unskip}%
    \def\@next{}%
  \fi \fi
  \@next
  }

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  network addresses

\def\netaddress{%
  \begingroup
  \def\CurrentTag{netaddress}%
  \@defaultoptions
  \@savingargumenttrue
  \let\@network\relax
  \def\network##1{\def\@network{##1: }}%
  \@SpecialsGetOther
  \makeescape\\%
  \netaddrat
  \netaddrpercent
  \@checkoptions}

{\makeactive\@
 \gdef\netaddrat{\makeactive\@\def@{\char"40\discretionary{}{}{}}}
 \makeactive\%
 \gdef\netaddrpercent{\makeactive\%\def%{\char"25\discretionary{}{}{}}}
}

%  We want the definition of \thenetaddress... to land at the right
%  nesting level, so we have to first pull it to the top, then
%  drop back to where we are.

\def\endnetaddress{%
  \global\toks@=\expandafter{\the\@argument}%
  \ifx\@network\relax
    \gdef\@@network{}%
  \else
    \xdef\@@network{\@network}%
  \fi
  \endgroup
  \expandafter\edef\csname thenetaddress\number\authornumber\endcsname
    {{\noexpand\rm\@@network}%
     {\noexpand\netaddrat\noexpand\netaddrpercent\noexpand\net
      \ignorespaces\the\toks@\unskip}}%
  }

\def\net{\tt}

%  Overrides to default author and signature formats

\def\authorlist#1{\def\@authorlist{#1}}

%  Except for the first article in a section, beginnings of articles
%  are announced by a horizontal rule the width of the column.
%  In the case that this rule happens to fall at the top of a column,
%  we have to make sure that it appears at the VERY top of the column
%  and not just on the first baseline.  To accomplish this, we insert
%  an empty rule first and then jump back over it to place the rule that
%  readers will see.

\def\article{%
  \@allowspanningfigsfalse
  \iftubsecondcolstart  % if splicing, start in col.2
    \null\newcol        % and set horizontal shift
    \tubcolwidthandgutter=\colwd \advance\tubcolwidthandgutter by \intercolwd
  \fi
  \ifSecTitle \global\SecTitlefalse
  \else \vskip\AboveTitleSkip
    \kern\topskip
    \nullhrule
    \kern-\topskip
    \kern-\strulethickness
    \hrule height\strulethickness depth\z@
    \nobreak
    \kern\medskipamount
  \fi
  \ifx\thetitle\relax
  \else
    \nobreak
    {\parskip\z@\interlinepenalty\@M
      \noindent\def\\{\unskip\break}\raggedstretch=.3\colwd\raggedright\bf
      \ignorespaces\thetitle\unskip\endgraf}%
  \fi
  \ifnum\authornumber&gt;0
    \nobreak
    \vskip4pt
    {\parskip\z@\interlinepenalty\@M
     \def\\{\unskip\hfil\break}\hangindent\parindent\raggedright
     \@authorlist\endgraf}
  \fi
  \nobreak
  \vskip \BelowTitleSkip
  \vskip -\parskip
  \tenpoint
  \DeleteOptionalSpacesandPars{\noindent\ignorespaces}%
  }


% without the \nobreak, we can end up with an empty last page
% (tb139wermuth-isdim). As Udo explains (13may24):
%  After TeX adjusts the page height the tugboat.sty output routine
%  starts the \ExecuteNextDC macro that prepares for a new page. This
%  page gets a \topskip and more input is read next. Only \endarticle is
%  left so a \vfill finishes the started column and your routine adds
%  another one to complete the page. That's all that ends up on the page.
% With the \nobreak, the signature will be put on the last page, and the
% previous page will be underfull, so it becomes obvious that a little
% space should be taken away somewhere.
\def\endarticle{\nobreak\vfil\end}

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  heads  *****
%

%  Heads are set by first saving the text of the head in \@argument
%  and then operating appropriately depending upon the \headlevel.
%  Selection among the different heads is made by an \ifcase.

%  To remove extra \par tokens between heads and ensuing text in the
%  input file, we call \DeleteOptionalSpacesandPars.  To do this outside
%  the `head' group and just before TeX returns to the normal input stream
%  following a call to \head, we must define (globally) a control sequence
%  (\@next) and call it at the very end.

\newcount\headlevel     \headlevel=1

\def\head{%
  \begingroup
  \def\CurrentTag{head}%
  \@allowindentfalse
  \@defaultoptions
  \@savingargumenttrue
  \def\\{\break}%
  \@checkoptions}

\def\endhead{%
  \endgraf
  \ifcase\headlevel\or\@domainhead\or\@dosubhead\or\@dosubsubhead\fi
  \endgroup
  \@next
  }

\def\@domainhead{%
  \if@removeprewhite\else\vskip\baselineskip\fi
  \noindent{\raggedright\bf\ignorespaces\the\@argument\unskip\endgraf}%
  \if@removepostwhite          %  usually we want the white space
  \else\kern0.5\baselineskip\fi
  \nobreak
  \gdef\@next{%
    \if@allowindent\def\@next{}%  usually we don't want to indent here
    \else\def\@next{\DeleteOptionalSpacesandPars{\noindent\ignorespaces}}\fi
    \@next
    }%
  }

\def\@dosubhead{%
  \if@removeprewhite\else\medskip\fi
  \noindent{\frenchspacing\bf\ignorespaces\the\@argument
    \unskip\if@headpunctuation.\fi}%
    \hskip 0.5em plus \fontdimen3\the\font
  \gdef\@next{\DeleteOptionalSpacesandPars{}}%
  }

\def\@dosubsubhead{%
  {\frenchspacing\bf\ignorespaces\the\@argument\unskip}%
    \hskip 0.5em plus \fontdimen3\the\font
  \gdef\@next{\DeleteOptionalSpacesandPars{}}%
  }

\def\subhead{\head[\headlevel=2]}
\def\subsubhead{\head[\headlevel=3]}

\newif\if@headpunctuation  \@headpunctuationtrue
\def\nopunctuation{\@headpunctuationfalse}

\newif\if@allowindent
\def\allowindent{\global\@allowindenttrue}

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  text and subtext  *****
%

%  The code here exists primarily to implement \subtext.  The treatment
%  is similar to that for \head in that an \ifcase statement is called
%  to choose between the various text levels.  Here, however, we handle
%  the `text' on the fly instead of saving it as an argument.

\newcount\textlevel     \textlevel=1

\def\text{%
  \begingroup
  \def\CurrentTag{text}%
  \@defaultoptions
  \@savingargumentfalse
  \@checkoptions}

\def\@begintext{%
  \endgraf
  \ifcase\textlevel\or\or\@setupsubtext\fi
  }

\def\@setupsubtext{%
  \vskip\abovedisplayskip
  \advance\leftskip by 0.5\parindent
  \advance\rightskip by 0.5\parindent
  \ninepoint\rm
  }

\def\endtext{%
  \gdef\@next{}%
  \ifcase\textlevel\or\or\@dosubtext\fi
  \endgroup
  \@next
  }

\def\@dosubtext{%
  \endgraf
  \vskip\belowdisplayskip
  \gdef\@next{\@asifbelowdisplay}%
  }

\def\subtext{\text[\textlevel=2]}

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  lists  *****
%

\newcount\listlevel     \listlevel=1
\newif\if@itemized
\newcount\itemnumber
\newtoks\@itemtag
\newcount\@cols                 % number of columns in list
\newdimen\colsepwidth
\newdimen\@listindent
\newdimen\@listhangindent
\newif\if@firstitem             % when first item is handled differently
\newtoks\everylist

\def\list{%
  \begingroup
  \def\CurrentTag{list}%
  \let\@liststyle=\@displaystyle
  \def\inline{\let\@liststyle=\@inlinestyle}%
  \def\display{\let\@liststyle=\@displaystyle}%
  \def\displaystyle##1{\def\@altdisplaystyle{##1}}%
  \def\inlinestyle##1{\def\@altinlinestyle{##1}}%
  \def\item{%
    \begingroup
    \def\CurrentTag{item}%
    \@numarguments=0
    \@checkoptions}%
  \@itemtag={$\bullet$}%
  \def\tag##1{\@itemtag{##1}}%
  \def\tagform##1{\llap{##1\strutt\enspace}}%
  \@itemizedtrue
  \def\unitemized{\@itemizedfalse}%
  \itemnumber=0
  \def\numbered{\@itemtag={\number\itemnumber.}}%
  \def\romannumeraled{\@itemtag={\romannumeral\itemnumber.}}%
  \def\Romannumeraled{\@itemtag=
    {\uppercase\expandafter{\romannumeral\itemnumber.}}}%
  \def\lettered{\itemnumber="60 \@itemtag={\char\itemnumber.}}%
  \def\Lettered{\itemnumber="40 \@itemtag={\char\itemnumber.}}%
  \def\ruled{\@ruledtrue}%
  \@ruledfalse
  \@cols=1
  \def\cols{\@cols}%
  \@firstitemtrue
  \def\@itemseparator{, }%
  \def\itemseparator##1{\def\@itemseparator{##1}}%
  \@defaultoptions
  \@savingargumentfalse
  \the\everylist
  \@checkoptions}

\def\@beginlist{%
  \ifx\@liststyle\@displaystyle
    \endgraf
    \ifnum\listlevel=1
      \if@ruled \if@removeprewhite\else\medskip\fi \hrule\kern5pt \nobreak
      \else \if@removeprewhite\else\vskip\abovedisplayskip \fi\fi
    \fi
    \advance\leftskip\parindent
    \@listindent=\parindent
    \@listhangindent=\@listindent
    \parindent\@listindent
    \lineskip\z@
    \if@itemized
    \else
      \parskip\z@skip
      \parindent\z@
      \raggedright
      \everypar={\advance\itemnumber\@ne
                 \tagform{\the\@itemtag}}%
      \makeCtrlMendgraf
    \fi
    \def\colsep{%
      \global\count@\itemnumber
      \egroup\kern\colsepwidth
      \vtop\bgroup
      \@altdisplaystyle
      \itemnumber=\count@\ignoreendline}%
    \ifnum\@cols&gt;1
      \dimen@\colsepwidth
      \multiply\dimen@\@cols
      \advance\dimen@-\colsepwidth
      \advance\hsize-\dimen@
      \divide\hsize by\@cols
      \hbox\bgroup\vtop\bgroup
    \fi
    \@altdisplaystyle
  \else
    \def\tagform##1{##1\strutt\ }%
    \if@itemized
    \else
       \makeCtrlMseparator
       \advance\itemnumber by \@ne
       \tagform{\the\@itemtag}%
    \fi
    \def\colsep{}%
    \@altinlinestyle
  \fi
  }


\def\endlist{%
  \ifx\@liststyle\@displaystyle
    \if@itemized\endgraf\fi
    \ifnum\@cols&gt;1
      \egroup   % vtop
      \egroup   % hbox
    \fi
    \ifnum\listlevel=1
      \if@ruled \kern5pt\hrule\nobreak\vskip2\medskipamount
      \else %\nobreak
        \if@removepostwhite\else\vskip\belowdisplayskip\fi
      \fi
      \gdef\@next{\@asifbelowdisplay}%
    \fi
  \else \gdef\@next{}%
  \fi
  \endgroup     % list
  \@next
  }

\def\sublist{\list[\listlevel=2]}


\newtoks\everyitem      \everyitem{}


\def\@beginitem{%
  \ifx\@liststyle\@displaystyle
    \endgraf
    \if@firstitem\@firstitemfalse\else\vskip\smallskipamount\fi
    \advance\itemnumber by \@ne
    \noindent\leavevmode
    \the\everyitem
    \tagform{\the\@itemtag}%
  \else
    \def\item{\if@firstitem\@firstitemfalse\else\unskip\@itemseparator\fi
              \advance\itemnumber by \@ne\the\@itemtag\enspace}%
  \fi
  \global\count@\itemnumber
  \global\dimen@\hangindent
  \endgroup
  \itemnumber\count@
  \hangindent\dimen@
  }

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  verbatim  *****
%

%  Operation here is very similar to that for the other tags.
%  The opening tag sets up the situation and looks for optional
%  commands and the short-form delimiters.  Since initial setup
%  involves changing the special characters to characters of
%  type other, some juggling must be done when optional commands
%  are read.  In addition, to allow for implementation of the
%  |...| style using the more verbose \verbatim...\endverbatim,
%  we parameterize the ending-delimiter.

        % sets default to display style
\def\verbatim{\@verbatim[\display]}

\def\@verbatim{%
  \begingroup
  \setupverbatim
  \@checkoptions
  }

\def\setupverbatim{%
  \def\CurrentTag{verbatim}%
  \@defaultoptions
  \def\inline{\let\@verbstyle\@inlinestyle}%
  \def\display{\par\smallverbdisplay\let\@verbstyle\@displaystyle}%
  \def\displaystyle##1{\def\@altdisplaystyle{##1}}%
  \def\inlinestyle##1{\def\@altinlinestyle{##1}}%
  \def\numbered{\@numberedtrue}%
  \def\ruled{\@ruledtrue}%
  \def\smallcode{\ninepoint\tt }%
  \let\@verbinputvar\relax
  \let\@verbinputfile\relax
  \@SpecialsGetOther
  \enddelim=\expandafter{\endverbdelimiter}%
  \normalspaces\frenchspacing
  \obeylines
  \@savingargumenttrue
  \the\everyverbatim
  }

% By default, switch to 9pt tt for verbatim displays.
\def\smallverbdisplay{\smallcode}

\def\@SpecialsGetOther{%
  \catcode`\\=\other
  \catcode`\{=\other \catcode`\}=\other \catcode`\$=\other
  \catcode`\&amp;=\other \catcode`\#=\other \catcode`\%=\other
  \catcode`\~=\other \catcode`\_=\other \catcode`\^=\other
  \the\@AdditionsToSpecialsGetOther}

%  The \@Additions... register above should be used whenever another
%  character is declared to be special for some purpose.  E.g.,
%  we will use the | for the short-form |...| verbatim notation.
%  Since the | is generally active for this purpose, its category
%  won't get changed to \other for use in \verbatim...\endverbatim
%  unless we add it via this mechanism.

\newtoks\@AdditionsToSpecialsGetOther

\def\AddToSpecialsGetOther#1{%
  \@AdditionsToSpecialsGetOther=
   \expandafter{\the\@AdditionsToSpecialsGetOther#1}}

%  Altering the verbatim setup.
%  Users can alter the setup to their purpose by
%  putting tokens in the register \everyverbatim.

\newtoks\everyverbatim

%  Ordinarily the end-tag would be the single token `\endverbatim'.
%  The following allows us to `see' the tag when `\' is of type `other'.
{\catcode`\|=0 \catcode`\\=\other
|gdef|endverbdelimiter{\endverbatim}}

%  Input from an external variable or file

\def\inputfromvar#1{\def\@verbinputvar{#1}}%
\def\inputfromfile#1{\def\@verbinputfile{#1}}%
\let\@verbinputvar\relax
\let\@verbinputfile\relax

%  Outputs

\newif\if@outputtotype  \@outputtotypetrue
\def\notype{\@outputtotypefalse}
\def\outputtovar#1{\def\@verboutputvar{#1}}
\def\outputtofile#1{\def\@verboutputfile{#1}}
\let\@verboutputvar\relax
\let\@verboutputfile\relax
\newwrite\verboutfile

\def\@beginverbatim{\obeyspaces}%\obeylines}

\def\endverbatim{%
 \ifx\@verboutputvar\relax\else         % output to `variable'
   \expandafter\xdef\csname\@verboutputvar\endcsname{\the\@argument}%
 \fi
 \ifx\@verboutputfile\relax\else        % output to file
   \immediate\openout\verboutfile=\@verboutputfile
   \makeCtrlMnewlinechar
   \iffalse{\fi\expandafter\@setupverbwrite\the\@argument}% use \@setupwrite to
   \immediate\closeout\verboutfile              % get rid of initial ^^M
 \fi
 \gdef\@next{}%                         % in case following clause is false
 \if@outputtotype                       % output typeset on page
  \tt
  \ifx\@verbstyle\@inlinestyle
    \@beforeverbinline
    \@altinlinestyle
  \else
    \@beforeverbdisplay
    \@altdisplaystyle
  \fi
  \ifx\@verbinputvar\relax\else         % input from `variable'
    \csname\@verbinputvar\endcsname
  \fi
  \ifx\@verbinputfile\relax\else        % input from file
    \fileinput{\@verbinputfile}%
    \@endverbatim
  \fi
  \expandafter\@ignoreCtrlMverbendline\the\@argument\@endverbatim
  \ifx\@verbstyle\@inlinestyle
    \@afterverbinline
  \else
    \@afterverbdisplay\gdef\@next{\@asifbelowdisplay}%
  \fi
 \fi
 \endgroup
 \@next
 }


\def\@beforeverbinline{%
    \makeCtrlMverbspace
    \let\@endverbatim=\empty
  }

\def\@beforeverbdisplay{%
  \def\@endverbatim{\verbendline}%
  \if@ruled \medskip \hrule\kern5pt \nobreak
  \else \vskip\abovedisplayskip
  \fi
  \makespaceverbspace
  \makeCtrlMverbendline
  \parskip=\z@skip
  \if@numbered \parindent=\z@
    \if@continuingnumbers
    \else \global\globallinenumber = \z@ \fi
    \linenumber=\z@ \fi
  \everypar={\global\advance\globallinenumber by\@ne
          \advance\linenumber by\@ne
          \ifnum\linenumber&lt;3 \vadjust{\nobreak}\fi
          \if@numbered \leavevmode
              \hbox to\normalparindent{\hss\sevenrm\the\globallinenumber.\ }%
          \fi}%
  \frenchspacing\rightskip=-\ttrightskip \hyphenpenalty\@M
  }

%  \ttrightskip is the permissible overhang beyond right margin for verbatim;
%  in MANMAC, this is 5pc, which is fine for the TeXbook, but much too
%  much here. Until 2020-10-07, this was 1pc, but that also looks to be
%  too much (we don't allow any overrun by default in LaTeX). The 2.9pt
%  value comes from a verbatim line in \ninett (the default), with the
%  standard \parindent (resetting that to zero seems too big a change)
%  that is 43 characters long; it's 2.89pt overfull, and doesn't look
%  terrible, so accept it. BTW \hfuzz=1pt in tugboat.sty.

\newdimen\ttrightskip \ttrightskip=2.9pt

\def\@afterverbinline{}

\def\@afterverbdisplay{%
  \if@ruled \kern5pt\hrule\fi
  \ifnum\linenumber&lt;3 \penalty\z@ \fi
  \if@removepostwhite\else
    \if@ruled \vskip2\medskipamount \else \vskip\belowdisplayskip\fi
  \fi
 }

\def\@asifbelowdisplay{%
  \toks@=\expandafter{\the\everypar}%
  \noindent
  \everypar=\expandafter{\the\toks@}%
  \ignorespaces}


%  Definitions of spaces and ^^M
%  \@ignoreCtrlMverbendline is used to lop off an initial ^^M in
%  verbatim text and to remove an \@endverbatim (the latter in case the
%  verbatim text is actually empty)

\def\@ignoreendverbatim{\@ignoreone{\@endverbatim}{}}
\def\verbendline{\leavevmode\null\endgraf}
\def\makeCtrlMactive{\catcode`\^^M=\active}
{\makeCtrlMactive
\gdef\makeCtrlMverbendline{\makeCtrlMactive%
 \def^^M{\@ignoreone{\@endverbatim}{\verbendline}}}%
\makeCtrlMverbendline%
\gdef\@ignoreCtrlMverbendline{\@ignoreone{
}{\@ignoreendverbatim}}%
\gdef\@setupverbwrite{\@ignoreone{
}{\immediate\write\verboutfile\bgroup}}%
\gdef\makeCtrlMverbspace{\makeCtrlMactive\def^^M{\verbatimspace}}%
\gdef\makeCtrlMnewlinechar{\newlinechar=`\^^M}%
\gdef\makeCtrlMendgraf{\makeCtrlMactive\def^^M{\strutt\endgraf}}%
\gdef\makeCtrlMseparator{\makeCtrlMactive%
  \def^^M{%
    \@checknexttoken {\endlist}{}{%
      \@itemseparator\advance\itemnumber by \@ne \tagform{\the\@itemtag}%
      \ignorespaces}}}%
}

%  to read a variable or file name properly, we must interpret
%  spaces and ^^M as nothing or as spaces

{\makeCtrlMactive\obeyspaces%
\gdef\makeCtrlMempty{\def^^M{}}%
\gdef\makespaceempty{\def {}}%
}
{\makeCtrlMactive\obeyspaces%
\gdef\makeCtrlMspace{\def^^M{\space}}%
\gdef\makespacespace{\def {\space}}%
}

{\makeCtrlMactive%
\gdef\@ignoreCtrlM#1{\@ignoreone{^^M}{#1}}%
\gdef\ignoreendline{\@ignoreCtrlM{}}%
}

%  From David Eppstein's ``Trees'' paper (6#1), preserve initial spaces.
\def\verbatimspace{\ifvmode\indent\fi\space}
{\obeyspaces\gdef\makespaceverbspace{\def {\verbatimspace}}}



%  Options and variants.

\def\verbinline{\@verbatim[\inline]}  % \@verbatim to avoid \display
\def\verbdisplay{\verbatim[\display]} % already the default, but what the heck
\def\verbfile#1{\verbatim[\inputfromfile{#1}]}


%  Verbatim with the other characters (e.g. |...|).
%  Procedures are parameterized so that it is easy to allow
%  different characters to perform this function.  Any character
%  that's chosen could cause problems if it occurs unexpectedly
%  in the middle of what is supposed to be verbatim text.  We call
%  the current special character for this purpose the "verbchar"
%  and store it in active form in the token register \@verbchar.

\newtoks\@verbchar

%  On hitting a "verbchar" in the middle of text, TeX must look ahead
%  to see whether the verbchar occurs again.  Since this
%  look-ahead fixes the category of the token examined, we must change
%  the categories of all characters appropriately before looking
%  (and we read \everyverbatim in case it contains a category change).
%  We must also "gobble" the second verbchar if we hit one.
%  Depending upon whether 1 or 2 verbchars are found, we call
%  \verbatim with the appropriate style command.  We also use an
%  optional command to change the delimiter which ends this \verbatim
%  block.  We naturally localize the changes to category codes made on
%  startup.  It's easier to end this group here at the beginning and to
%  restart everything in a standard \verbatim than it is to add an extra
%  \endgroup after the verbatim text.

\def\@firstverbchar{%
  \begingroup
  \setupverbatim
%  \@SpecialsGetOther
  \makeverbcharactive
  \expandafter\@checknexttoken\expandafter{\the\@verbchar}%
    {\expandafter\@ignoreone\expandafter{\the\@verbchar}%
      {\endgroup\verbatim[\longform\maketwoendverb]}}%
    {\endgroup\@verbatim[\inline\longform\makeoneendverb]}%
  }

\def\setupverbchar{%
 \def\makeoneendverb{\catcode\expandafter`\csname\expandafter
        \string\the\@verbchar\endcsname=
    \active\edef\endverbdelimiter{\the\@verbchar}%
    \enddelim=\expandafter{\endverbdelimiter}}%
  \def\maketwoendverb{\catcode\expandafter`\csname\expandafter
        \string\the\@verbchar\endcsname=
    \active\edef\endverbdelimiter{\the\@verbchar\the\@verbchar}%
    \enddelim=\expandafter{\endverbdelimiter}}%
  \expandafter\let\the\@verbchar\@firstverbchar
  \makeverbcharactive
  \AddToSpecialsGetOther{%
    \catcode\expandafter`\csname
        \expandafter\string\the\@verbchar\endcsname=\other}%
  }

\def\makeverbcharactive{%
  \catcode\expandafter`\csname
        \expandafter\string\the\@verbchar\endcsname=\active}

{\makeother\| \gdef\VertChar{|}}
{\makeactive\|
\gdef\makevertverbchar{%
  \@verbchar={|}%
  \setupverbchar
  }
}

{\makeother\! \gdef\WowChar{!}}
{\makeactive\!
\gdef\makewowverbchar{%
  \@verbchar={!}%
  \setupverbchar
  }
}


\def\MTH{$}
\def\sb{_}
\def\sp{^}
\def\SP{{\tt\char"20 }}         % "visible" space
\chardef\bs=`\\
\def\vrt{{\tt\char`\|}}
\def\brokenvert{\hbox to 5.24998pt{\hfill
  \lower 1.5pt\vbox to 8.5pt{\hrule width .9pt height 3.25pt
  \vfill\hrule width .9pt height 3.25pt}\hfill}}



\def\@lt{$&lt;$}
\def\@gt{$&gt;$}
{\makeactive\&lt;
\gdef\enablemetacode{%
  \AddToSpecialsGetOther{\catcode`\&lt;=\other}%
  \makeactive\&lt;%
  \def&lt;##1&gt;{$\langle${\it\makeCtrlMspace\makespacespace##1\/}$\rangle$}%
  }
}

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  figures  *****
%

\newif\if@@mid  \@@midfalse
\newif\if@@bot  \@@botfalse
\def\@caption{}
\def\abovecaptionskip{\vskip\abovecaptionskipamount}
\newskip\abovecaptionskipamount \abovecaptionskipamount=3pt plus2pt minus1pt

\newif\if@fixed \@fixedfalse

        % items for top and bottom ``banners'' on first page
\def\resetfirsthead{\global\toplgt=\z@ \gdef\firsthead{}}
\resetfirsthead
\newbox\firsth@@d       \newbox\firsth@ad

\def\resetfirstfoot{\global\botlgt=\z@ \gdef\firstfoot{}}
\resetfirstfoot
\newbox\firstf@@t       \newbox\firstf@ot

\newif\if@allowspanningfigs

\newcount\@figurepage
\newcount\@figurescol
\newcount\@figureecol


\def\figure{%
  \begingroup
  \def\CurrentTag{figure}%
  \@defaultoptions
  \@savingargumentfalse
  \def\top{}%
  \def\bot{\@@bottrue}%
  \def\mid{\@@midtrue}%
  \def\caption##1{\def\@caption{{\abovecaptionskip##1\smallskip}}}%
  \def\fixed{\@fixedtrue}%
  \def\scol{\@figurescol}%
  \def\ecol{\@figureecol}%
  \@figurepage=\pageno
  \@figurescol=1
  \@figureecol=\numcols
  \def\page{%
    \@ignoreall{\space}%
      {\@ignoreone{=}%
         {\@ignoreall{\space}%
            {\@checknexttoken{+}{\@ignoreone{+}{\advance\@figurepage by}}%
                 {\@figurepage=}%
            }%
         }%
      }%
    }%
  \@checkoptions}

\def\@beginfigure{%
  \if@fixed
    \global\ThisIsFirstPagetrue
    \setbox\T@stBox=\vbox\bgroup \hsize\pagewd
  \else
    \if@@mid\midinsert\else\if@@bot\botinsert\else\topinsert\fi\fi
  \fi
  }

\def\endfigure{%
  \@caption
  \if@fixed
    \egroup
    \if@allowspanningfigs
      \ifnum\@figurepage&gt;\pageno
        \immediate\write\sixt@@n{^^J
           Setting multiple column figures currently not allowed on pages^^J
           other than the first of each article.  Check your source file.^^J}%
      \else
        \if@@bot
          \ifdim \botlgt=\z@ \global\botlgt=\ht\T@stBox \resetpagelgt \fi
          \global\setbox\firstf@ot=\vbox to \botlgt{\box\T@stBox \vfil}%
          \global\setbox\firstf@@t=\vbox to \botlgt{\vfil}%
          \gdef\firstfoot{\ifnum \xcol=2 \copy\firstf@ot
                                  \else \copy\firstf@@t \fi }%
        \else
          \ifdim \toplgt=\z@ \global\toplgt=\ht\T@stBox \resetpagelgt \fi
%                       assume that \firsth@ad ends with glue, hence no \dp
          \global\setbox\firsth@ad=\vbox to \toplgt{\box\T@stBox \vfil}%
          \global\setbox\firsth@@d=\vbox to \toplgt{\vfil}%
          \gdef\firsthead{\ifnum \xcol=2 \box\firsth@ad
                                  \else \copy\firsth@@d \fi }%
        \fi
      \fi
    \else
      \immediate\write\sixt@@n{^^J
         Setting multiple column figures currently not allowed after^^J
         article has begun.^^J}%
    \fi
  \else \endinsert
  \fi
  \endgroup
  }

\def\twocolfigure{%
  \figure[\fixed]}

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  utilities  *****
%

\def\linebreak{\unskip\break}           % conflicts with LaTeX definition

%  Define a structure that will permit a list (using \obeylines)
%  to be made into 2 columns, split by \vsplit, indented the
%  normal \parindent

\def\NormalizeBlockHeight{%
  \TestCount=1                         % \@ne
  \TestDimen=\dimen0 \advance\TestDimen by-\topskip
  \CutOneLine }
\def\CutOneLine{%
  \advance\TestCount by 1 \advance\TestDimen by-\baselineskip
  \ifdim\TestDimen &lt; \baselineskip                        % \@ne
     \def\result{%
       \TestDimen=\baselineskip
       \multiply\TestDimen by \TestCount
       \advance\TestDimen by \topskip
       \global\dimen0=\TestDimen }%
  \else \def\result{\CutOneLine }\fi
  \result }

\def\twosplit{%
  {\topskip=\baselineskip \splittopskip=\topskip
   \setbox0=\copy\TestBox
   \dimen0=\ht\TestBox
   \NormalizeBlockHeight
   \divide\dimen0 by 2
   \setbox\LeftHalf=\vsplit\TestBox to \dimen0
   \ifdim\ht\TestBox &gt; \ht\LeftHalf
     \advance\dimen0 by \baselineskip
     \setbox\TestBox=\copy0
     \setbox\LeftHalf=\vsplit\TestBox to \dimen0
   \fi
   \line{\kern\parindent\valign{##\vfil\cr
         \unvbox\LeftHalf\cr\noalign{\hfil}\unvbox\TestBox\cr}}%
   }%
  \global\setbox0=\null}

\newbox\LeftHalf
\newdimen\HalfWd
\HalfWd=\twocolcolwd
\advance\HalfWd by-\normalparindent
\divide\HalfWd by 2

{\obeylines
\gdef\twouplist #1{%
  \topskip=\baselineskip \splittopskip=\topskip
  \begingroup \parindent=\z@ \obeylines
%                       next line ends with intentional &lt;cr&gt;
  \def\endtwouplist{
    \egroup %               % end of \vbox
    \endgroup %             % end of \obeylines group
    \twosplit }%
  \global\setbox\TestBox=\vbox\bgroup\hsize=\HalfWd %
    \indent\vrule height\topskip width \z@ #1}%
}

%  Tags for special formatting of editor's notes  (See also TUGBOAT.COM)

\def\Editor{\noindent To the Editor:\par}
\def\EdNote #1{%
  \if #1[%
    \ifvmode \smallskip\noindent \else \unskip\hskip1em \fi
    [\thinspace\xEdNote\ignorespaces
  \else \ifFirstPar \else \medskip\noindent \fi
  \xEdNote #1\fi }



%       Draw a box around a whole page, e.g. announcements page;
%       format must be \onenarrow or \onemedium, and start on a new page.

\def\bigbox{\hrule \hbox\bgroup \vrule\kern 1pc
        \vbox\bgroup \vskip 1pc }
\def\endbox{\endgraf \vskip 1pc \egroup \kern 1pc\vrule \egroup \hrule }

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%     *****  initialization  *****
%

\def\initializearticle{%
  \let\thetitle=\relax
  \authornumber=0
  \def\@signature{\@defaultsignature}%
  \def\@authorlist{\@defaultauthorlist}%
  \@allowspanningfigstrue
  }


\makeother\@

%               @ is prohibited in AMS-TeX, but should not be in TUGboat


\twocol
\maxcols=2
\hfuzz=1pt                     % don't worry about small overfulls
\OverlaysinTeXtrue
\Trimmarksfalse
\PrelimDrafttrue
\initializearticle
\pageno=901                    % number of title page

% Stretchy spacing was the default for many years, but in 2012 it
% looked too stretchy. Comment out.
%\StretchyTenPointSpacing
%\StretchyNinePointSpacing
%\StretchyEightPointSpacing

\makevertverbchar

\endinput

%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  History of changes

Version   Date        Changes
-------   ---------   ---------------------------------------------------
1.31      26 Oct 24   \thedoi: use \tbissident.
                      \endarticle: avoid empty last page, also for
                      tb139wermuth-isdim.

1.30      15 Apr 24   implement \iftubsecondcolstart for tb139wermuth-isdim.

1.29      28 Oct 23   introduce \abovecaptionskipamount, reduce to \smallskip
                      a la ltugboat.

1.28      11 Jun 23   \tenpoint in footer, not just \tenrm.

1.27      19 May 22   \tbhurl belatedly defined.

1.26      12 Mar 22   DOI support; define \@, \OpTeX; reduce \ttrightskip;
                      author separator always comma, no "and";
                      support \acro in all point sizes and all font variants;
                      macro cleanups.

1.25      12 Jun 19   \tenpoint \rm: reset \sl to \tensl,
                      since the \tenpoint \bf changes it to \tenbfsl.

1.24       5 Sep 18   only version number bump to match tugboat.cmn.

1.23      19 Mar 17   define \manual and \manualsl in each of \tenpoint,
                      \ninepoint, \eightpoint; define \SMC in \eightpoint.
                      
1.22       7 Nov 16   \smallcode: do not reduce baselineskip.
                      \abovecaptionskip: generalize \bigskip; no change
                      to default.
                      \pageno: start at 901 to make LaTeX.
                      \hfuzz: initialize to 1pt to match existing practice.

1.21 &lt;skipped this version number&gt;

1.20      22 May 12   Do not hyphenate in typewriter.
                      Add footnote hooks.
                      No \Stretchy*Spacing by default.
                      \smallcode for verbatim displays (not inline)
                        via \smallverbdisplay.

1.19       4 Mar 11   added \r

1.18       4 Feb 11   changed \rfoot to give same results as LaTeX class

1.17       3 Jun 06   clarified copyright.

1.16       2 Jan 06   updated TUG address and phone in header

1.15      15 Aug 05   added switch \if@address to avoid skip in signature

1.14c     14 Oct 96   lowered footnoterule by 3pt

1.14b     14 Apr 94   added \interlinepenalty=10000 to avoid page breaks
                        in very long titles and author lists

1.14a      8 Nov 93   removed extraneous " from header

1.14      19 Feb 93   installed new TUG address and phone number in header

1.13      13 Oct 92   Added \SMC in \ninepoint

1.12       4 Jun 92   Added stretchability to \rightskip in ragged title

1.11       8 Mar 92   Changed name of tugboat.com to tugboat.cmn to avoid
                        conflict with special meaning of .com with some
                        operating systems
                      Within verbatim, added \smallcode (from tugproc)
                      Added standard headers, prepared for archive installation

1.10      21 Oct 91   Corrected font for \SMC in \tenpoint to \ninerm
                        (\ninesmc was used, but set to cmcsc10)
                      Changed \EdNote to detect \ifvmode when tag followed
                        by [ and to \smallskip and \noindent in that case
                        rather than performing \hskip1em

1.09      11 Mar 91   Made \ an escape character in network addresses.
                      Added mechanism for saving \long arguments of
                        TUGboat macros (see uses of \@long).

1.08      18 Oct 90   Incorporated redefinition of \sl within \bf
                      Changed an \input within \verbatim to \fileinput.
                      Added means of turning off punctuation after subheads.
                      Removed \nobreak after lists
1.07       8 Jun 90   Corrected definition of \newpage

1.06      13 May 90   Added \@setupverbwrite to eliminate initial ^^M
                      as \verbatim writes to a file.

                      Made strut on first line of footnote slightly taller
                      so as to separate footnotes.

                      Reset \@verbinputfile and \@verbinputvar to \relax
                      to allow nesting

                      Removed some \global assignments to \@argument and
                      2 verbatim flags to allow nesting.

1.05      23 Apr 90   Added "\setupverbatim" to \@firstverbchar so
                      that category switches are accomodated properly.

1.04       7 Mar 90   Added \colsepwidth to allow for separation between
                      columns of lists

1.03       1 Mar 90   Modified \@dosubhead and \@dosubsubhead to allow
                      stretchable space afterward

1.02      25 Feb 90   Added \resetmaxcols to allow for automatic adjustment
                      of \maxcols; if overlays are done by the driver,
                      \maxcols needs to be set to an overall job maximum
                      at the start of the job.

                      Added setting of \SecTitletrue to definition
                      of \sectitle.

                      Added indicator of style file loaded (\tubstyle).

1.01      17 Jan 90   Modified \@executetoend so that \@next would not
                      be clobbered by \csname @begin\CurrentTag\endcsname;
                      \@next changed to \@afterbegintag

                      Added `\the' before \@otherSFD within definition of
                      \@shortparse

                      added \@altdisplaystyle to definition of \colsep
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