doc-src/rail.sty

Rewrite the Probability theory.

Introduced pinfreal as real numbers with infinity.
Use pinfreal as value for measures.
Introduces Lebesgue Measure based on the integral in Multivariate Analysis.
Proved Radon Nikodym for arbitrary sigma finite measure spaces.

% rail.sty - style file to support railroad diagrams
%
% 09-Jul-90 L. Rooijakkers
% 08-Oct-90 L. Rooijakkers	fixed centering bug when \rail@tmpc<0.
% 07-Feb-91 L. Rooijakkers	added \railoptions command, indexing
% 08-Feb-91 L. Rooijakkers	minor fixes
% 28-Jun-94 K. Barthelmann	turned into LaTeX2e package
% 08-Dec-96 K. Barthelmann	replaced \@writefile
% 13-Dec-96 K. Barthelmann	cleanup
% 22-Feb-98 K. Barthelmann	fixed catcodes of special characters
% 18-Apr-98 K. Barthelmann	fixed \par handling
% 19-May-98 J. Olsson		Added new macros to support arrow heads.
% 26-Jul-98 K. Barthelmann	changed \par to output newlines
%
% This style file needs to be used in conjunction with the 'rail'
% program. Running LaTeX as 'latex file' produces file.rai, which should be
% processed by Rail with 'rail file'. This produces file.rao, which will
% be picked up by LaTeX on the next 'latex file' run.
%
% LaTeX will warn if there is no file.rao or it's out of date.
%
% The macros in this file thus consist of two parts: those that read and
% write the .rai and .rao files, and those that do the actual formatting
% of the railroad diagrams.

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{rail}[1998/05/19]

% railroad diagram formatting parameters (user level)
% all of these are copied into their internal versions by \railinit
%
% \railunit : \unitlength within railroad diagrams
% \railextra : extra length at outside of diagram
% \railboxheight : height of ovals and frames
% \railboxskip : vertical space between lines
% \railboxleft : space to the left of a box
% \railboxright : space to the right of a box
% \railovalspace : extra space around contents of oval
% \railframespace : extra space around contents of frame
% \railtextleft : space to the left of text
% \railtextright : space to the right of text
% \railtextup : space to lift text up
% \railjoinsize : circle size of join/split arcs
% \railjoinadjust : space to adjust join
%
% \railnamesep : separator between name and rule body

\newlength\railunit
\newlength\railextra
\newlength\railboxheight
\newlength\railboxskip
\newlength\railboxleft
\newlength\railboxright
\newlength\railovalspace
\newlength\railframespace
\newlength\railtextleft
\newlength\railtextright
\newlength\railtextup
\newlength\railjoinsize
\newlength\railjoinadjust
\newlength\railnamesep

% initialize the parameters

\setlength\railunit{1sp}
\setlength\railextra{4ex}
\setlength\railboxleft{1ex}
\setlength\railboxright{1ex}
\setlength\railovalspace{2ex}
\setlength\railframespace{2ex}
\setlength\railtextleft{1ex}
\setlength\railtextright{1ex}
\setlength\railjoinadjust{0pt}
\setlength\railnamesep{1ex}

\DeclareOption{10pt}{
  \setlength\railboxheight{16pt}
  \setlength\railboxskip{24pt}
  \setlength\railtextup{5pt}
  \setlength\railjoinsize{16pt}
}
\DeclareOption{11pt}{
  \setlength\railboxheight{16pt}
  \setlength\railboxskip{24pt}
  \setlength\railtextup{5pt}
  \setlength\railjoinsize{16pt}
}
\DeclareOption{12pt}{
  \setlength\railboxheight{20pt}
  \setlength\railboxskip{28pt}
  \setlength\railtextup{6pt}
  \setlength\railjoinsize{20pt}
}

\ExecuteOptions{10pt}
\ProcessOptions

% internal versions of the formatting parameters
%
% \rail@extra   : \railextra
% \rail@boxht   : \railboxheight
% \rail@boxsp   : \railboxskip
% \rail@boxlf   : \railboxleft
% \rail@boxrt   : \railboxright
% \rail@boxhht  : \railboxheight / 2
% \rail@ovalsp  : \railovalspace
% \rail@framesp : \railframespace
% \rail@textlf  : \railtextleft
% \rail@textrt  : \railtextright
% \rail@textup  : \railtextup
% \rail@joinsz  : \railjoinsize
% \rail@joinhsz : \railjoinsize / 2
% \rail@joinadj : \railjoinadjust
%
% \railinit : internalize all of the parameters.

\newcount\rail@extra
\newcount\rail@boxht
\newcount\rail@boxsp
\newcount\rail@boxlf
\newcount\rail@boxrt
\newcount\rail@boxhht
\newcount\rail@ovalsp
\newcount\rail@framesp
\newcount\rail@textlf
\newcount\rail@textrt
\newcount\rail@textup
\newcount\rail@joinsz
\newcount\rail@joinhsz
\newcount\rail@joinadj

\newcommand\railinit{
\rail@extra=\railextra
\divide\rail@extra by \railunit
\rail@boxht=\railboxheight
\divide\rail@boxht by \railunit
\rail@boxsp=\railboxskip
\divide\rail@boxsp by \railunit
\rail@boxlf=\railboxleft
\divide\rail@boxlf by \railunit
\rail@boxrt=\railboxright
\divide\rail@boxrt by \railunit
\rail@boxhht=\railboxheight
\divide\rail@boxhht by \railunit
\divide\rail@boxhht by 2
\rail@ovalsp=\railovalspace
\divide\rail@ovalsp by \railunit
\rail@framesp=\railframespace
\divide\rail@framesp by \railunit
\rail@textlf=\railtextleft
\divide\rail@textlf by \railunit
\rail@textrt=\railtextright
\divide\rail@textrt by \railunit
\rail@textup=\railtextup
\divide\rail@textup by \railunit
\rail@joinsz=\railjoinsize
\divide\rail@joinsz by \railunit
\rail@joinhsz=\railjoinsize
\divide\rail@joinhsz by \railunit
\divide\rail@joinhsz by 2
\rail@joinadj=\railjoinadjust
\divide\rail@joinadj by \railunit
}

\AtBeginDocument{\railinit}

% \rail@param : declarations for list environment
%
% \railparam{TEXT} : sets \rail@param to TEXT
%
% \rail@reserved : characters reserved for grammar

\newcommand\railparam[1]{
\def\rail@param{
  \setlength\leftmargin{0pt}\setlength\rightmargin{0pt}
  \setlength\labelwidth{0pt}\setlength\labelsep{0pt}
  \setlength\itemindent{0pt}\setlength\listparindent{0pt}
  #1
}
}
\railparam{}

\newtoks\rail@reserved
\rail@reserved={:;|*+?[]()'"}

% \rail@termfont : format setup for terminals
%
% \rail@nontfont : format setup for nonterminals
%
% \rail@annofont : format setup for annotations
%
% \rail@rulefont : format setup for rule names
%
% \rail@indexfont : format setup for index entry
%
% \railtermfont{TEXT} : set terminal format setup to TEXT
%
% \railnontermfont{TEXT} : set nonterminal format setup to TEXT
%
% \railannotatefont{TEXT} : set annotation format setup to TEXT
%
% \railnamefont{TEXT} : set rule name format setup to TEXT
%
% \railindexfont{TEXT} : set index entry format setup to TEXT

\def\rail@termfont{\ttfamily\upshape}
\def\rail@nontfont{\rmfamily\upshape}
\def\rail@annofont{\rmfamily\itshape}
\def\rail@namefont{\rmfamily\itshape}
\def\rail@indexfont{\rmfamily\itshape}

\newcommand\railtermfont[1]{
\def\rail@termfont{#1}
}

\newcommand\railnontermfont[1]{
\def\rail@nontfont{#1}
}

\newcommand\railannotatefont[1]{
\def\rail@annofont{#1}
}

\newcommand\railnamefont[1]{
\def\rail@namefont{#1}
}

\newcommand\railindexfont[1]{
\def\rail@indexfont{#1}
}

% railroad read/write macros
%
% \begin{rail} TEXT \end{rail} : TEXT is written out to the .rai file,
%                                as \rail@i{NR}{TEXT}. Then the matching
%                                \rail@o{NR}{FMT} from the .rao file is
%                                executed (if defined).
%
% \railoptions{OPTIONS} : OPTIONS are written out to the .rai file,
%                         as \rail@p{OPTIONS}.
%
% \railterm{IDENT,IDENT,...} : format IDENT as terminals. writes out
%                              \rail@t{IDENT} to the .rai file
%
% \railalias{IDENT}{TEXT} : format IDENT as TEXT. defines \rail@t@IDENT as
%                           TEXT.
%
% \railtoken{IDENT}{TEXT} : abbreviates \railalias{IDENT}{TEXT}\railterm{IDENT}
%                           (for backward compatibility)
%
% \rail@setcodes : guards special characters
%
% \rail@makeother{CHARACTER} : sets \catcode of CHARACTER to "other"
%                              used inside a loop for \rail@setcodes
%
% \rail@nr : railroad diagram counter
%
% \ifrail@match : current \rail@i{NR}{TEXT} matches
%
% \rail@first : actions to be done first. read in .rao file,
%               open .rai file if \@filesw true, undefine \rail@first.
%               executed from \begin{rail}, \railoptions and \railterm.
%
% \rail@i{NR}{TEXT} : defines \rail@i@NR as TEXT. written to the .rai
%                     file by \rail, read from the .rao file by
%                     \rail@first
%
% \rail@t{IDENT} : tells Rail that IDENT is to be custom formatted,
%                  written to the .rai file by \railterm.
%
% \rail@o{NR}{TEXT} : defines \rail@o@NR as TEXT, read from the .rao
%                     file by \rail@first.
%
% \rail@p{OPTIONS} : pass options to rail, written to the .rai file by
%                    \railoptions
%
% \rail@write{TEXT} : write TEXT to the .rai file
%
% \rail@warn : warn user for mismatching diagrams
%
% \rail@endwarn : either \relax or \rail@warn
%
% \ifrail@all : checked at the end of the document

\def\rail@makeother#1{
  \expandafter\catcode\expandafter`\csname\string #1\endcsname=12
}

\def\rail@setcodes{
\let\par=\relax
\let\\=\relax
\expandafter\@tfor\expandafter\rail@symbol\expandafter:\expandafter=%
  \the\rail@reserved
\do{\expandafter\rail@makeother\rail@symbol}
}

\newcount\rail@nr

\newif\ifrail@all
\rail@alltrue

\newif\ifrail@match

\def\rail@first{
\begingroup
\makeatletter
\rail@setcodes
\InputIfFileExists{\jobname.rao}{}{\PackageInfo{rail}{No file \jobname.rao}}
\makeatother
\endgroup
\if@filesw
\newwrite\tf@rai
\immediate\openout\tf@rai=\jobname.rai
\fi
\global\let\rail@first=\relax
}

\long\def\rail@body#1\end{
{
\newlinechar=`^^J
\def\par{\string\par^^J}
\rail@write{\string\rail@i{\number\rail@nr}{#1}}
}
\xdef\rail@i@{#1}
\end
}

\newenvironment{rail}{
\global\advance\rail@nr by 1
\rail@first
\begingroup
\rail@setcodes
\rail@body
}{
\endgroup
\rail@matchtrue
\@ifundefined{rail@o@\number\rail@nr}{\rail@matchfalse}{}
\expandafter\ifx\csname rail@i@\number\rail@nr\endcsname\rail@i@
\else
\rail@matchfalse
\fi
\ifrail@match
\csname rail@o@\number\rail@nr\endcsname
\else
\PackageWarning{rail}{Railroad diagram {\number\rail@nr} doesn't match}
\global\let\rail@endwarn=\rail@warn
\begin{list}{}{\rail@param}
\rail@begin{1}{}
\rail@setbox{\bfseries ???}
\rail@oval
\rail@end
\end{list}
\fi
}

\newcommand\railoptions[1]{
\rail@first
\rail@write{\string\rail@p{#1}}
}

\newcommand\railterm[1]{
\rail@first
\@for\rail@@:=#1\do{
\rail@write{\string\rail@t{\rail@@}}
}
}

\newcommand\railalias[2]{
\expandafter\def\csname rail@t@#1\endcsname{#2}
}

\newcommand\railtoken[2]{\railalias{#1}{#2}\railterm{#1}}

\long\def\rail@i#1#2{
\expandafter\gdef\csname rail@i@#1\endcsname{#2}
}

\def\rail@o#1#2{
\expandafter\gdef\csname rail@o@#1\endcsname{
\begin{list}{}{\rail@param}
#2
\end{list}
}
}

\def\rail@t#1{}

\def\rail@p#1{}

\long\def\rail@write#1{\@ifundefined{tf@rai}{}{\immediate\write\tf@rai{#1}}}

\def\rail@warn{
\PackageWarningNoLine{rail}{Railroad diagram(s) may have changed.
                            Use 'rail' and rerun}
}

\let\rail@endwarn=\relax

\AtEndDocument{\rail@endwarn}

% index entry macro
%
% \rail@index{IDENT} : add index entry for IDENT

\def\rail@index#1{
\index{\rail@indexfont#1}
}

% railroad formatting primitives
%
% \rail@x : current x
% \rail@y : current y
% \rail@ex : current end x
% \rail@sx : starting x for \rail@cr
% \rail@rx : rightmost previous x for \rail@cr
%
% \rail@tmpa : temporary count
% \rail@tmpb : temporary count
% \rail@tmpc : temporary count
%
% \rail@put : put at (\rail@x,\rail@y)
% \rail@vput : put vector at (\rail@x,\rail@y)
%
% \rail@eline : end line by drawing from \rail@ex to \rail@x
%
% \rail@vreline : end line by drawing a vector from \rail@x to \rail@ex
%
% \rail@vleline : end line by drawing a vector from \rail@ex to \rail@x
%
% \rail@sety{LEVEL} : set \rail@y to level LEVEL

\newcount\rail@x
\newcount\rail@y
\newcount\rail@ex
\newcount\rail@sx
\newcount\rail@rx

\newcount\rail@tmpa
\newcount\rail@tmpb
\newcount\rail@tmpc

\def\rail@put{\put(\number\rail@x,\number\rail@y)}

\def\rail@vput{\put(\number\rail@ex,\number\rail@y)}

\def\rail@eline{
\rail@tmpb=\rail@x
\advance\rail@tmpb by -\rail@ex
\rail@put{\line(-1,0){\number\rail@tmpb}}
}

\def\rail@vreline{
\rail@tmpb=\rail@x
\advance\rail@tmpb by -\rail@ex
\rail@vput{\vector(1,0){\number\rail@tmpb}}
}

\def\rail@vleline{
\rail@tmpb=\rail@x
\advance\rail@tmpb by -\rail@ex
\rail@put{\vector(-1,0){\number\rail@tmpb}}
}

\def\rail@sety#1{
\rail@y=#1
\multiply\rail@y by -\rail@boxsp
\advance\rail@y by -\rail@boxht
}

% \rail@begin{HEIGHT}{NAME} : begin a railroad diagram of height HEIGHT
%
% \rail@end : end a railroad diagram
%
% \rail@expand{IDENT} : expand IDENT

\def\rail@begin#1#2{
\item
\begin{minipage}[t]{\linewidth}
\ifx\@empty#2\else
{\rail@namefont \rail@expand{#2}}\\*[\railnamesep]
\fi
\unitlength=\railunit
\rail@tmpa=#1
\multiply\rail@tmpa by \rail@boxsp
\begin{picture}(0,\number\rail@tmpa)(0,-\number\rail@tmpa)
\rail@ex=0
\rail@rx=0
\rail@x=\rail@extra
\rail@sx=\rail@x
\rail@sety{0}
}

\def\rail@end{
\advance\rail@x by \rail@extra
\rail@eline
\end{picture}
\end{minipage}
}

\def\rail@vend{
\advance\rail@x by \rail@extra
\rail@vreline
\end{picture}
\end{minipage}
}

\def\rail@expand#1{\@ifundefined{rail@t@#1}{#1}{\csname rail@t@#1\endcsname}}

% \rail@token{TEXT}[ANNOT] : format token TEXT with annotation
% \rail@ltoken{TEXT}[ANNOT] : format token TEXT with annotation, arrow left
% \rail@rtoken{TEXT}[ANNOT] : format token TEXT with annotation, arrow right
%
% \rail@ctoken{TEXT}[ANNOT] : format token TEXT centered with annotation
% \rail@lctoken{TEXT}[ANNOT] : format token TEXT centered with annotation, arrow left
% \rail@rctoken{TEXT}[ANNOT] : format token TEXT centered with annotation, arrow right
%
% \rail@nont{TEXT}[ANNOT] : format nonterminal TEXT with annotation
% \rail@lnont{TEXT}[ANNOT] : format nonterminal TEXT with annotation, arrow left
% \rail@rnont{TEXT}[ANNOT] : format nonterminal TEXT with annotation. arrow right
%
% \rail@cnont{TEXT}[ANNOT] : format nonterminal TEXT centered with annotation
% \rail@lcnont{TEXT}[ANNOT] : format nonterminal TEXT centered with annotation,
%                             arrow left
% \rail@rcnont{TEXT}[ANNOT] : format nonterminal TEXT centered with annotation,
%                             arrow right
%
% \rail@term{TEXT}[ANNOT] : format terminal TEXT with annotation
% \rail@lterm{TEXT}[ANNOT] : format terminal TEXT with annotation, arrow left
% \rail@rterm{TEXT}[ANNOT] : format terminal TEXT with annotation, arrow right
%
% \rail@cterm{TEXT}[ANNOT] : format terminal TEXT centered with annotation
% \rail@lcterm{TEXT}[ANNOT] : format terminal TEXT centered with annotation, arrow left
% \rail@rcterm{TEXT}[ANNOT] : format terminal TEXT centered with annotation,
%                             arrow right
%
% \rail@annote[TEXT] : format TEXT as annotation

\def\rail@token#1[#2]{
\rail@setbox{%
{\rail@termfont \rail@expand{#1}}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@oval
}

\def\rail@ltoken#1[#2]{
\rail@setbox{%
{\rail@termfont \rail@expand{#1}}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@vloval
}

\def\rail@rtoken#1[#2]{
\rail@setbox{%
{\rail@termfont \rail@expand{#1}}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@vroval
}

\def\rail@ctoken#1[#2]{
\rail@setbox{%
{\rail@termfont \rail@expand{#1}}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@coval
}

\def\rail@lctoken#1[#2]{
\rail@setbox{%
{\rail@termfont \rail@expand{#1}}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@vlcoval
}

\def\rail@rctoken#1[#2]{
\rail@setbox{%
{\rail@termfont \rail@expand{#1}}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@vrcoval
}

\def\rail@nont#1[#2]{
\rail@setbox{%
{\rail@nontfont \rail@expand{#1}}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@frame
}

\def\rail@lnont#1[#2]{
\rail@setbox{%
{\rail@nontfont \rail@expand{#1}}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@vlframe
}

\def\rail@rnont#1[#2]{
\rail@setbox{%
{\rail@nontfont \rail@expand{#1}}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@vrframe
}

\def\rail@cnont#1[#2]{
\rail@setbox{%
{\rail@nontfont \rail@expand{#1}}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@cframe
}

\def\rail@lcnont#1[#2]{
\rail@setbox{%
{\rail@nontfont \rail@expand{#1}}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@vlcframe
}

\def\rail@rcnont#1[#2]{
\rail@setbox{%
{\rail@nontfont \rail@expand{#1}}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@vrcframe
}

\def\rail@term#1[#2]{
\rail@setbox{%
{\rail@termfont #1}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@oval
}

\def\rail@lterm#1[#2]{
\rail@setbox{%
{\rail@termfont #1}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@vloval
}

\def\rail@rterm#1[#2]{
\rail@setbox{%
{\rail@termfont #1}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@vroval
}

\def\rail@cterm#1[#2]{
\rail@setbox{%
{\rail@termfont #1}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@coval
}

\def\rail@lcterm#1[#2]{
\rail@setbox{%
{\rail@termfont #1}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@vlcoval
}

\def\rail@rcterm#1[#2]{
\rail@setbox{%
{\rail@termfont #1}\ifx\@empty#2\else\ {\rail@annofont #2}\fi
}
\rail@vrcoval
}

\def\rail@annote[#1]{
\rail@setbox{\rail@annofont #1}
\rail@text
}

% \rail@box : temporary box for \rail@oval and \rail@frame
%
% \rail@setbox{TEXT} : set \rail@box to TEXT, set \rail@tmpa to width
%
% \rail@oval : format \rail@box of width \rail@tmpa inside an oval
% \rail@vloval : format \rail@box of width \rail@tmpa inside an oval, vector left
% \rail@vroval : format \rail@box of width \rail@tmpa inside an oval, vector right
%
% \rail@coval : same as \rail@oval, but centered between \rail@x and
%               \rail@mx
% \rail@vlcoval : same as \rail@oval, but centered between \rail@x and
%                 \rail@mx, vector left
% \rail@vrcoval : same as \rail@oval, but centered between \rail@x and
%                 \rail@mx, vector right
%
% \rail@frame : format \rail@box of width \rail@tmpa inside a frame
% \rail@vlframe : format \rail@box of width \rail@tmpa inside a frame, vector left
% \rail@vrframe : format \rail@box of width \rail@tmpa inside a frame, vector right
%
% \rail@cframe : same as \rail@frame, but centered between \rail@x and
%                \rail@mx
% \rail@vlcframe : same as \rail@frame, but centered between \rail@x and
%                  \rail@mx, vector left
% \rail@vrcframe : same as \rail@frame, but centered between \rail@x and
%                  \rail@mx, vector right
%
% \rail@text : format \rail@box of width \rail@tmpa above the line

\newbox\rail@box

\def\rail@setbox#1{
\setbox\rail@box\hbox{\strut#1}
\rail@tmpa=\wd\rail@box
\divide\rail@tmpa by \railunit
}

\def\rail@oval{
\advance\rail@x by \rail@boxlf
\rail@eline
\advance\rail@tmpa by \rail@ovalsp
\ifnum\rail@tmpa<\rail@boxht\rail@tmpa=\rail@boxht\fi
\rail@tmpb=\rail@tmpa
\divide\rail@tmpb by 2
\advance\rail@y by -\rail@boxhht
\rail@put{\makebox(\number\rail@tmpa,\number\rail@boxht){\box\rail@box}}
\advance\rail@y by \rail@boxhht
\advance\rail@x by \rail@tmpb
\rail@put{\oval(\number\rail@tmpa,\number\rail@boxht)}
\advance\rail@x by \rail@tmpb
\rail@ex=\rail@x
\advance\rail@x by \rail@boxrt
}

\def\rail@vloval{
\advance\rail@x by \rail@boxlf
\rail@eline
\advance\rail@tmpa by \rail@ovalsp
\ifnum\rail@tmpa<\rail@boxht\rail@tmpa=\rail@boxht\fi
\rail@tmpb=\rail@tmpa
\divide\rail@tmpb by 2
\advance\rail@y by -\rail@boxhht
\rail@put{\makebox(\number\rail@tmpa,\number\rail@boxht){\box\rail@box}}
\advance\rail@y by \rail@boxhht
\advance\rail@x by \rail@tmpb
\rail@put{\oval(\number\rail@tmpa,\number\rail@boxht)}
\advance\rail@x by \rail@tmpb
\rail@ex=\rail@x
\advance\rail@x by \rail@boxrt
\rail@vleline
}

\def\rail@vroval{
\advance\rail@x by \rail@boxlf
\rail@vreline
\advance\rail@tmpa by \rail@ovalsp
\ifnum\rail@tmpa<\rail@boxht\rail@tmpa=\rail@boxht\fi
\rail@tmpb=\rail@tmpa
\divide\rail@tmpb by 2
\advance\rail@y by -\rail@boxhht
\rail@put{\makebox(\number\rail@tmpa,\number\rail@boxht){\box\rail@box}}
\advance\rail@y by \rail@boxhht
\advance\rail@x by \rail@tmpb
\rail@put{\oval(\number\rail@tmpa,\number\rail@boxht)}
\advance\rail@x by \rail@tmpb
\rail@ex=\rail@x
\advance\rail@x by \rail@boxrt
}

\def\rail@coval{
\rail@tmpb=\rail@tmpa
\advance\rail@tmpb by \rail@ovalsp
\ifnum\rail@tmpb<\rail@boxht\rail@tmpb=\rail@boxht\fi
\advance\rail@tmpb by \rail@boxlf
\advance\rail@tmpb by \rail@boxrt
\rail@tmpc=\rail@mx
\advance\rail@tmpc by -\rail@x
\advance\rail@tmpc by -\rail@tmpb
\divide\rail@tmpc by 2
\ifnum\rail@tmpc>0
\advance\rail@x by \rail@tmpc
\fi
\rail@oval
}

\def\rail@vlcoval{
\rail@tmpb=\rail@tmpa
\advance\rail@tmpb by \rail@ovalsp
\ifnum\rail@tmpb<\rail@boxht\rail@tmpb=\rail@boxht\fi
\advance\rail@tmpb by \rail@boxlf
\advance\rail@tmpb by \rail@boxrt
\rail@tmpc=\rail@mx
\advance\rail@tmpc by -\rail@x
\advance\rail@tmpc by -\rail@tmpb
\divide\rail@tmpc by 2
\ifnum\rail@tmpc>0
\advance\rail@x by \rail@tmpc
\fi
\rail@vloval
}

\def\rail@vrcoval{
\rail@tmpb=\rail@tmpa
\advance\rail@tmpb by \rail@ovalsp
\ifnum\rail@tmpb<\rail@boxht\rail@tmpb=\rail@boxht\fi
\advance\rail@tmpb by \rail@boxlf
\advance\rail@tmpb by \rail@boxrt
\rail@tmpc=\rail@mx
\advance\rail@tmpc by -\rail@x
\advance\rail@tmpc by -\rail@tmpb
\divide\rail@tmpc by 2
\ifnum\rail@tmpc>0
\advance\rail@x by \rail@tmpc
\fi
\rail@vroval
}

\def\rail@frame{
\advance\rail@x by \rail@boxlf
\rail@eline
\advance\rail@tmpa by \rail@framesp
\ifnum\rail@tmpa<\rail@boxht\rail@tmpa=\rail@boxht\fi
\advance\rail@y by -\rail@boxhht
\rail@put{\framebox(\number\rail@tmpa,\number\rail@boxht){\box\rail@box}}
\advance\rail@y by \rail@boxhht
\advance\rail@x by \rail@tmpa
\rail@ex=\rail@x
\advance\rail@x by \rail@boxrt
}

\def\rail@vlframe{
\advance\rail@x by \rail@boxlf
\rail@eline
\advance\rail@tmpa by \rail@framesp
\ifnum\rail@tmpa<\rail@boxht\rail@tmpa=\rail@boxht\fi
\advance\rail@y by -\rail@boxhht
\rail@put{\framebox(\number\rail@tmpa,\number\rail@boxht){\box\rail@box}}
\advance\rail@y by \rail@boxhht
\advance\rail@x by \rail@tmpa
\rail@ex=\rail@x
\advance\rail@x by \rail@boxrt
\rail@vleline
}

\def\rail@vrframe{
\advance\rail@x by \rail@boxlf
\rail@vreline
\advance\rail@tmpa by \rail@framesp
\ifnum\rail@tmpa<\rail@boxht\rail@tmpa=\rail@boxht\fi
\advance\rail@y by -\rail@boxhht
\rail@put{\framebox(\number\rail@tmpa,\number\rail@boxht){\box\rail@box}}
\advance\rail@y by \rail@boxhht
\advance\rail@x by \rail@tmpa
\rail@ex=\rail@x
\advance\rail@x by \rail@boxrt
}

\def\rail@cframe{
\rail@tmpb=\rail@tmpa
\advance\rail@tmpb by \rail@framesp
\ifnum\rail@tmpb<\rail@boxht\rail@tmpb=\rail@boxht\fi
\advance\rail@tmpb by \rail@boxlf
\advance\rail@tmpb by \rail@boxrt
\rail@tmpc=\rail@mx
\advance\rail@tmpc by -\rail@x
\advance\rail@tmpc by -\rail@tmpb
\divide\rail@tmpc by 2
\ifnum\rail@tmpc>0
\advance\rail@x by \rail@tmpc
\fi
\rail@frame
}

\def\rail@vlcframe{
\rail@tmpb=\rail@tmpa
\advance\rail@tmpb by \rail@framesp
\ifnum\rail@tmpb<\rail@boxht\rail@tmpb=\rail@boxht\fi
\advance\rail@tmpb by \rail@boxlf
\advance\rail@tmpb by \rail@boxrt
\rail@tmpc=\rail@mx
\advance\rail@tmpc by -\rail@x
\advance\rail@tmpc by -\rail@tmpb
\divide\rail@tmpc by 2
\ifnum\rail@tmpc>0
\advance\rail@x by \rail@tmpc
\fi
\rail@vlframe
}

\def\rail@vrcframe{
\rail@tmpb=\rail@tmpa
\advance\rail@tmpb by \rail@framesp
\ifnum\rail@tmpb<\rail@boxht\rail@tmpb=\rail@boxht\fi
\advance\rail@tmpb by \rail@boxlf
\advance\rail@tmpb by \rail@boxrt
\rail@tmpc=\rail@mx
\advance\rail@tmpc by -\rail@x
\advance\rail@tmpc by -\rail@tmpb
\divide\rail@tmpc by 2
\ifnum\rail@tmpc>0
\advance\rail@x by \rail@tmpc
\fi
\rail@vrframe
}

\def\rail@text{
\advance\rail@x by \rail@textlf
\advance\rail@y by \rail@textup
\rail@put{\box\rail@box}
\advance\rail@y by -\rail@textup
\advance\rail@x by \rail@tmpa
\advance\rail@x by \rail@textrt
}

% alternatives
%
% \rail@jx \rail@jy : current join point
%
% \rail@gx \rail@gy \rail@gex \rail@grx : global versions of \rail@x etc,
%                                         to pass values over group closings
%
% \rail@mx : maximum x so far
%
% \rail@sy : starting \rail@y for alternatives
%
% \rail@jput : put at (\rail@jx,\rail@jy)
%
% \rail@joval[PART] : put \oval[PART] with adjust

\newcount\rail@jx
\newcount\rail@jy

\newcount\rail@gx
\newcount\rail@gy
\newcount\rail@gex
\newcount\rail@grx

\newcount\rail@sy
\newcount\rail@mx

\def\rail@jput{
\put(\number\rail@jx,\number\rail@jy)
}

\def\rail@joval[#1]{
\advance\rail@jx by \rail@joinadj
\rail@jput{\oval(\number\rail@joinsz,\number\rail@joinsz)[#1]}
\advance\rail@jx by -\rail@joinadj
}

% \rail@barsplit : incoming split for '|'
%
% \rail@plussplit : incoming split for '+'
%

\def\rail@barsplit{
\advance\rail@jy by -\rail@joinhsz
\rail@joval[tr]
\advance\rail@jx by \rail@joinhsz
}

\def\rail@plussplit{
\advance\rail@jy by -\rail@joinhsz
\advance\rail@jx by \rail@joinsz
\rail@joval[tl]
\advance\rail@jx by -\rail@joinhsz
}

% \rail@alt{SPLIT} : start alternatives with incoming split SPLIT
%

\def\rail@alt#1{
\rail@sy=\rail@y
\rail@jx=\rail@x
\rail@jy=\rail@y
\advance\rail@x by \rail@joinsz
\rail@mx=0
\let\rail@list=\@empty
\let\rail@comma=\@empty
\let\rail@split=#1
\begingroup
\rail@sx=\rail@x
\rail@rx=0
}

% \rail@nextalt{FIX}{Y} : start next alternative at vertical position Y
%                         and fix-up FIX
%

\def\rail@nextalt#1#2{
\global\rail@gx=\rail@x
\global\rail@gy=\rail@y
\global\rail@gex=\rail@ex
\global\rail@grx=\rail@rx
\endgroup
#1
\ifnum\rail@gx>\rail@mx\rail@mx=\rail@gx\fi
\ifnum\rail@grx>\rail@mx\rail@mx=\rail@grx\fi
\edef\rail@list{\rail@list\rail@comma\number\rail@gex:\number\rail@gy}
\def\rail@comma{,}
\rail@split
\let\rail@split=\@empty
\rail@sety{#2}
\rail@tmpa=\rail@jy
\advance\rail@tmpa by -\rail@y
\advance\rail@tmpa by -\rail@joinhsz
\rail@jput{\line(0,-1){\number\rail@tmpa}}
\rail@jy=\rail@y
\advance\rail@jy by \rail@joinhsz
\advance\rail@jx by \rail@joinhsz
\rail@joval[bl]
\advance\rail@jx by -\rail@joinhsz
\rail@ex=\rail@x
\begingroup
\rail@sx=\rail@x
\rail@rx=0
}

% \rail@barjoin : outgoing join for first '|' alternative
%
% \rail@plusjoin : outgoing join for first '+' alternative
%
% \rail@altjoin : join for subsequent alternative
%

\def\rail@barjoin{
\ifnum\rail@y<\rail@sy
\global\rail@gex=\rail@jx
\else
\global\rail@gex=\rail@ex
\fi
\advance\rail@jy by -\rail@joinhsz
\rail@joval[tl]
\advance\rail@jx by -\rail@joinhsz
\ifnum\rail@y<\rail@sy
\rail@altjoin
\fi
}

\def\rail@plusjoin{
\global\rail@gex=\rail@ex
\advance\rail@jy by -\rail@joinhsz
\advance\rail@jx by -\rail@joinsz
\rail@joval[tr]
\advance\rail@jx by \rail@joinhsz
}

\def\rail@altjoin{
\rail@eline
\rail@tmpa=\rail@jy
\advance\rail@tmpa by -\rail@y
\advance\rail@tmpa by -\rail@joinhsz
\rail@jput{\line(0,-1){\number\rail@tmpa}}
\rail@jy=\rail@y
\advance\rail@jy by \rail@joinhsz
\advance\rail@jx by -\rail@joinhsz
\rail@joval[br]
\advance\rail@jx by \rail@joinhsz
}

% \rail@eltsplit EX:Y; : split EX:Y into \rail@ex \rail@y
%
% \rail@endalt{JOIN} : end alternatives with outgoing join JOIN

\def\rail@eltsplit#1:#2;{\rail@ex=#1\rail@y=#2}

\def\rail@endalt#1{
\global\rail@gx=\rail@x
\global\rail@gy=\rail@y
\global\rail@gex=\rail@ex
\global\rail@grx=\rail@rx
\endgroup
\ifnum\rail@gx>\rail@mx\rail@mx=\rail@gx\fi
\ifnum\rail@grx>\rail@mx\rail@mx=\rail@grx\fi
\edef\rail@list{\rail@list\rail@comma\number\rail@gex:\number\rail@gy}
\rail@x=\rail@mx
\rail@jx=\rail@x
\rail@jy=\rail@sy
\advance\rail@jx by \rail@joinsz
\let\rail@join=#1
\@for\rail@elt:=\rail@list\do{
\expandafter\rail@eltsplit\rail@elt;
\rail@join
\let\rail@join=\rail@altjoin
}
\rail@x=\rail@mx
\rail@y=\rail@sy
\rail@ex=\rail@gex
\advance\rail@x by \rail@joinsz
}

% \rail@bar : start '|' alternatives
%
% \rail@nextbar : next '|' alternative
%
% \rail@endbar : end '|' alternatives
%

\def\rail@bar{
\rail@alt\rail@barsplit
}

\def\rail@nextbar{
\rail@nextalt\relax
}

\def\rail@endbar{
\rail@endalt\rail@barjoin
}

% \rail@plus : start '+' alternatives
%
% \rail@nextplus: next '+' alternative
%
% \rail@endplus : end '+' alternatives
%

\def\rail@plus{
\rail@alt\rail@plussplit
}

\def\rail@nextplus{
\rail@nextalt\rail@fixplus
}

\def\rail@fixplus{
\ifnum\rail@gy<\rail@sy
\begingroup
\rail@x=\rail@gx
\rail@y=\rail@gy
\rail@ex=\rail@gex
\rail@rx=\rail@grx
\ifnum\rail@x<\rail@rx
\rail@x=\rail@rx
\fi
\rail@eline
\rail@jx=\rail@x
\rail@jy=\rail@y
\advance\rail@jy by \rail@joinhsz
\rail@joval[br]
\advance\rail@jx by \rail@joinhsz
\rail@tmpa=\rail@sy
\advance\rail@tmpa by -\rail@joinhsz
\advance\rail@tmpa by -\rail@jy
\rail@jput{\line(0,1){\number\rail@tmpa}}
\rail@jy=\rail@sy
\advance\rail@jy by -\rail@joinhsz
\advance\rail@jx by \rail@joinhsz
\rail@joval[tl]
\advance\rail@jy by \rail@joinhsz
\global\rail@gx=\rail@jx
\global\rail@gy=\rail@jy
\global\rail@gex=\rail@gx
\global\rail@grx=\rail@rx
\endgroup
\fi
}

\def\rail@endplus{
\rail@endalt\rail@plusjoin
}

% \rail@cr{Y} : carriage return to vertical position Y

\def\rail@cr#1{
\rail@tmpa=\rail@sx
\advance\rail@tmpa by \rail@joinsz
\ifnum\rail@x<\rail@tmpa\rail@x=\rail@tmpa\fi
\rail@eline
\rail@jx=\rail@x
\rail@jy=\rail@y
\advance\rail@x by \rail@joinsz
\ifnum\rail@x>\rail@rx\rail@rx=\rail@x\fi
\advance\rail@jy by -\rail@joinhsz
\rail@joval[tr]
\advance\rail@jx by \rail@joinhsz
\rail@sety{#1}
\rail@tmpa=\rail@jy
\advance\rail@tmpa by -\rail@y
\advance\rail@tmpa by -\rail@boxsp
\advance\rail@tmpa by -\rail@joinhsz
\rail@jput{\line(0,-1){\number\rail@tmpa}}
\rail@jy=\rail@y
\advance\rail@jy by \rail@boxsp
\advance\rail@jy by \rail@joinhsz
\advance\rail@jx by -\rail@joinhsz
\rail@joval[br]
\advance\rail@jy by -\rail@joinhsz
\rail@tmpa=\rail@jx
\advance\rail@tmpa by -\rail@sx
\advance\rail@tmpa by -\rail@joinhsz
\rail@jput{\line(-1,0){\number\rail@tmpa}}
\rail@jx=\rail@sx
\advance\rail@jx by \rail@joinhsz
\advance\rail@jy by -\rail@joinhsz
\rail@joval[tl]
\advance\rail@jx by -\rail@joinhsz
\rail@tmpa=\rail@boxsp
\advance\rail@tmpa by -\rail@joinsz
\rail@jput{\line(0,-1){\number\rail@tmpa}}
\advance\rail@jy by -\rail@tmpa
\advance\rail@jx by \rail@joinhsz
\rail@joval[bl]
\rail@x=\rail@jx
\rail@ex=\rail@x
}