Quelle  zed.sty

% -- zed.sty version 2 -------------------------------------------------

% usual common sense conditions apply - see for example the LaTeX
% public license - try to avoid editing this file; if you do edit it,
% change the filename; comments, complaints, and suggestions to
%
%   Jim.Davies@comlab.ox.ac.uk 
%
% but all gratitude and appreciation to Mike Spivey.  

% This might be seen as a prototype; the functionality is there, but
% the implementation and documentation leave something to be
% desired---if anyone who _really_ knows what they are doing
% w.r.t. 2e internals wants to suggest revisions, then please do.

% The times option uses composite arrows (I mean, _really_ composite)
% and doesn't give the upharpoon symbol for filter and project - you
% get an \uparrow instead.  If you want the AMS versions of the
% symbols, then you'll need to define them yourself.  

% Actually, the mathtime fonts leave quite a lot to desired, if you're
% setting Z documents.  No disrespect intended, but the fontset is
% clearly aimed at traditional textbook mathematics, not software
% engineering.  

% changes:
%
% 14 July 2001: improved \surj in Lucida; removed \vcenter@enlarge
% from arrow definitions; \where and other zskips now use hbox's to
% handle color changes

% -- interface ---------------------------------------------------------

\def\fileversion{2.0} \def\filedate{2001/07/14}

\NeedsTeXFormat{LaTeX2e}

\ProvidesPackage{zed}[{\filedate\space\fileversion\space zed package}]

% --  options ----------------------------------------------------------

\newif\if@cm@ \@cm@false
\newif\if@lucida@ \@lucida@false
\newif\if@times@ \@times@false
\newif\if@color@ \@color@false
\newif\if@zed@ \@zed@false
\newif\if@csp@ \@csp@false

\DeclareOption{cm}{\@cm@true\@lucida@false\@times@false}
\DeclareOption{lucida}{\@cm@false\@lucida@true\@times@false}
\DeclareOption{times}{\@cm@false\@lucida@false\@times@true}
\DeclareOption{color}{\@color@true}
\DeclareOption{zed}{\@zed@true}
\DeclareOption{csp}{\@csp@true}
\DeclareOption{nolines}{}

\ExecuteOptions{cm} \ProcessOptions

\newif\if@zedsyntax@ \@zedsyntax@true

\@ifpackageloaded{csp}{%
  \if@zed@\else\@zedsyntax@false\fi
  }{%
  \if@csp@\RequirePackageWithOptions{csp}\fi
  }

% -- color -------------------------------------------------------------

\if@color@
  \@ifpackageloaded{color}{\relax}{%
    \RequirePackage[dvipsnames,usenames]{color}}
  \definecolor{ZedBoxColor}{cmyk}{1,1,1,1}
  %\definecolor{ZedBoxColor}{cmyk}{0,0.61,0.87,0}
  \definecolor{AnnotationColor}{cmyk}{1,1,1,1}
  \definecolor{ZedColor}{cmyk}{1,1,1,1}
\else
  \@ifpackageloaded{color}{\relax}{\def\color#1{\relax}}%
\fi

% -- fonts -------------------------------------------------------------

\DeclareMathVersion{zed}

\if@lucida@
  \@ifpackageloaded{lucidabr}{%
    }{%
    \RequirePackage{texnansi}
    \RequirePackage[expert,altbullet]{lucidabr}}
\fi

\if@times@
  \@ifpackageloaded{mathtime}{%
    }{%
    \RequirePackage{texnansi}
    \RequirePackage[LY1]{mathtime}}
  \SetSymbolFont{operators}   {zed}{\operator@encoding}{ptm}{m}{n}
  \SetSymbolFont{letters}     {zed}{MY1}{mtt}{m}{it}
  \SetSymbolFont{symbols}     {zed}{MY2}{mtt}{m}{n}
  \SetSymbolFont{largesymbols}{zed}{MY3}{mtt}{m}{n}
  \SetMathAlphabet{\mathrm}{zed}{\encodingdefault}{\rmdefault}{m}{n}%
  \SetMathAlphabet{\mathbf}{zed}{\encodingdefault}{\rmdefault}{bx}{n}%
  \SetMathAlphabet{\mathsf}{zed}{\encodingdefault}{\sfdefault}{m}{n}%
  \SetMathAlphabet{\mathtt}{zed}{\encodingdefault}{\ttdefault}{m}{n}
  \let\mathbb=\mathbf
  \let\smallfrown\undefined
  \DeclareMathSymbol\smallfrown{\mathrel}{symbols}{065}
  \let\vartriangleright\triangleleft
  \let\vartriangleleft\triangleright
  \def\sqsubset{\setbox0=\hbox{$\sqsubseteq$}%
    \ooalign{\vrule width 0.4pt height \ht0 depth 0pt\hfil\cr%
      \vbox to \ht0{%
        \hrule width\wd0 height 0.2pt depth 0.2pt
        \vss
        \hrule width\wd0 height 0.2pt depth 0.2pt}
      \hfil\cr}}
\fi

\if@cm@
  \DeclareSymbolFontAlphabet{\mathrm}{operators}
  \DeclareSymbolFontAlphabet{\mathit}{letters}
  \DeclareSymbolFontAlphabet{\mathcal}{symbols}
  \SetMathAlphabet{\mathrm}{zed}{\encodingdefault}{\rmdefault}{m}{n}
  \SetMathAlphabet{\mathbf}{zed}{\encodingdefault}{\rmdefault}{bx}{n}
  \SetMathAlphabet{\mathsf}{zed}{\encodingdefault}{\sfdefault}{m}{n}
  \SetMathAlphabet{\mathtt}{zed}{\encodingdefault}{\ttdefault}{m}{n}
  %%
  \DeclareSymbolFont{AMSa}{U}{msa}{m}{n}
  \DeclareSymbolFont{AMSb}{U}{msb}{m}{n}
  \DeclareSymbolFontAlphabet{\mathbb}{AMSb}
  \let\twoheadrightarrow\undefined
  \let\upharpoonright\undefined
  \let\upharpoonleft\undefined
  \let\rightarrowtail\undefined
  \let\sqsubset\undefined
  \let\smallfrown\undefined
  \let\vartriangleright\undefined
  \let\vartriangleleft\undefined
  \DeclareMathSymbol\twoheadrightarrow{\mathrel}{AMSa}{"10}
  \DeclareMathSymbol\upharpoonright{\mathrel}{AMSa}{"16}
  \DeclareMathSymbol\upharpoonleft{\mathrel}{AMSa}{"18}
  \DeclareMathSymbol\rightarrowtail{\mathrel}{AMSa}{"1A}
  \DeclareMathSymbol\sqsubset{\mathrel}{AMSa}{"40}
  \DeclareMathSymbol\smallfrown{\mathrel}{AMSa}{"61}
  \DeclareMathSymbol\vartriangleright{\mathrel}{AMSa}{"42}
  \DeclareMathSymbol\vartriangleleft{\mathrel}{AMSa}{"43}
\fi

\mathversion{zed}

% -- math codes and symbol definitions ---------------------------------

\DeclareSymbolFont{italics}{\encodingdefault}{\rmdefault}{m}{it}

\def\@setmcodes#1#2#3{{\count0=#1 \count1=#3
    \loop \global\mathcode\count0=\count1 \ifnum \count0<#2
    \advance\count0 by1 \advance\count1 by1 \repeat}}
\@setmcodes{`A}{`Z}{"7\hexnumber@\symitalics41}% 
\@setmcodes{`a}{`z}{"7\hexnumber@\symitalics61}% 

\def~{\ifmmode\,\else\penalty\@M\ \fi}

\let\@mc=\mathchardef \mathcode`\;="8000 {\catcode`\;=\active
  \gdef;{\semicolon\;}} \@mc\semicolon="603B

\def\_{\leavevmode \ifmmode\else\kern0.06em\fi \vbox{\hrule
    width0.5em}} 

\mathcode`\"="8000 \def\@kwote#1"{\hbox{\it #1}} {\catcode`\"=\active
  \global\let"=\@kwote}

\mathchardef\spot="320F

\mathcode`\|=\mid

\def\simple@enlarge#1{\mathchoice{%
    \hbox{\large$#1$}}{\hbox{\large$#1$}}{\hbox{\small$#1$}%
    }{\hbox{\small$#1$}}}
\def\simple@Enlarge#1{\mathchoice{%
    \hbox{\Large$#1$}}{\hbox{\Large$#1$}}{\hbox{\normalsize$#1$}%
    }{\hbox{\normalsize$#1$}}}
\def\vcenter@enlarge#1{\mathchoice{%
    \vcenter{\hbox{\large$#1$}}}{\vcenter{\hbox{\large$#1$}}%
    }{\vcenter{\hbox{\small$#1$}}}{\vcenter{\hbox{\small$#1$}}}}

\def\strut@op#1{\mathop{\mathstrut{#1}}\nolimits}

\let\lambda@sym=\lambda
\let\mu@sym=\mu 
\let\forall@sym=\forall 
\let\exists@sym=\exists

\def\uminus@sym{\setbox0=\hbox{$\cup$}\rlap{\hbox 
    to\wd0{\hss\raise0.3ex\hbox{$\scriptscriptstyle{-}$}\hss}}\box0}

\if@cm@
  \def\comp@sym{\raise 0.6ex\hbox{\small\oalign{\hfil%
        $\scriptscriptstyle\mathrm{o}$\hfil%
        \cr\hfil$\scriptscriptstyle\mathrm{9}$\hfil}}}
  \def\lbag@sym{{[}\mkern-2mu{[}}
  \def\rbag@sym{{]}\mkern-2mu{]}}
  \def\extract@sym{\upharpoonleft}
  \def\project@sym{\upharpoonright}
  \let\dres@sym\vartriangleleft
  \let\rres@sym\vartriangleright
  \def\ndres@sym{\rlap{\raise.05ex\hbox{$-$}}{\vartriangleleft}}
  \def\nrres@sym{\rlap{\raise.05ex\hbox{$-$}}{\vartriangleright}}
  \def\inv@sym{\sim}
  \def\cat@sym{\smash{\raise 0.8ex\hbox{$\smallfrown$}}}
  \def\inbag@sym{\rlap{\hbox{$-$}}{\sqsubset}}
  %
  \def\@p#1{\mathrel{\ooalign{\hfil$\mapstochar\mkern 5mu$\hfil\cr$#1$}}} 
  \def\@f#1{\mathrel{\ooalign{\hfil$\mapstochar\mkern 3mu%
    \mapstochar\mkern 5mu$\hfil\cr$#1$}}}
  %
  \let\rel\leftrightarrow
  \let\fun\rightarrow
  \let\inj\rightarrowtail
  \def\surj{\mathrel{\ooalign{$\fun$\hfil\cr$\mkern4mu\fun$}}}
  \def\bij{\mathrel{\ooalign{$\inj$\hfil\cr$\mkern5mu\fun$}}}
  \def\pfun{\@p\fun}
  \def\pinj{\@p\inj}
  \def\psurj{\@p\surj}
  \def\pbij{\@p\bij}
  \def\ffun{\@f\fun}
  \def\finj{\@f\inj}
\fi

\if@times@
  \def\comp@sym{\raise 0.6ex\hbox{\small\oalign{\hfil%
        $\scriptscriptstyle\mathrm{o}$\hfil%
        \cr\hfil$\scriptscriptstyle\mathrm{9}$\hfil}}}
  \def\lbag@sym{{[}\mkern-2mu{[}}
  \def\rbag@sym{{]}\mkern-2mu{]}}
  \def\extract@sym{\upharpoonleft}
  \def\project@sym{\upharpoonright}
  \def\dres@sym{\simple@Enlarge\vartriangleleft}
  \def\rres@sym{\simple@Enlarge\vartriangleright}
  \def\ndres@sym{%
    \rlap{\raise.08ex\hbox{$-$}}{\simple@Enlarge\vartriangleleft}}
  \def\nrres@sym{%
    \rlap{\raise.08ex\hbox{$-$}}{\simple@Enlarge\vartriangleright}}
  \def\inv@sym{\sim}
  \def\cat@sym{\mkern-6mu{\smallfrown}\mkern3mu}
  \def\inbag@sym{\setbox0=\hbox{$\sqsubseteq$}%
    \ooalign{\vrule width 0.4pt height \ht0 depth 0pt\hfil\cr%
      \vbox to \ht0{%
        \hrule width\wd0 height 0.2pt depth 0.2pt
        \vss
        \hrule width\wd0 height 0.2pt depth 0.2pt
        \vss
        \hrule width\wd0 height 0.2pt depth 0.2pt}
      \hfil\cr}}
  %
  \def\@p#1{\mathrel{\ooalign{$\mkern 16mu\mapstochar$\hfil\cr$#1$}}} 
  \def\@f#1{\mathrel{\ooalign{$\mkern 15mu\mapstochar\mkern 2mu%
    \mapstochar$\hfil\cr$#1$}}}
  %
  \def\extract@sym{\simple@enlarge{\uparrow}}
  \def\project@sym{\simple@enlarge{\uparrow}}
  \def\long@line@sym{$\mkern 6mu$---$\mkern -10.5mu$---}
  \def\short@line@sym{$\mkern 11mu$---$\mkern -16mu$---}
  \def\rel{%
    \mathrel{\ooalign{\long@line@sym\hfil\cr%
        \raise0.1pt\hbox{${\prec}\mkern 10mu{\succ}$}}}}
  \def\fun{%
    \mathrel{\ooalign{\long@line@sym\hfil\cr%
        \raise0.1pt\hbox{$\mkern 24mu\succ$\hfil}}}}
  \def\inj{%
    \mathrel{\ooalign{\short@line@sym\hfil\cr%
        \raise0.1pt\hbox{${\succ}\mkern 10mu{\succ}$\hfil}}}}
  \def\surj{%
    \mathrel{\ooalign{\long@line@sym\hfil\cr%
        \raise0.1pt\hbox{$\mkern 21mu{\succ}\mkern -10mu{\succ}$\hfil}}}}
  \def\bij{%
    \mathrel{\ooalign{\short@line@sym\hfil\cr%
        \raise0.1pt\hbox{%
          ${\succ}\mkern 7mu{\succ}\mkern -10mu{\succ}$\hfil}}}}
  \def\pfun{\@p\fun}
  \def\pinj{\@p\inj}
  \def\psurj{\@p\surj}
  \def\pbij{\@p\bij}
  \def\ffun{\@f\fun}
  \def\finj{\@f\inj}
\fi

\if@lucida@
  \def\@p#1{\ooalign{\hfil$\mapstochar\mkern 8mu$\hfil\cr$#1$}}
  \def\@f#1{\ooalign{\hfil$\mapstochar\mkern 2mu%
    \mapstochar\mkern 6mu$\hfil\cr$#1$}}
  \DeclareMathSymbol{\pinj@sym}{\mathbin}{arrows}{146}
  \def\surj@sym{\ooalign{$\rightarrow$\hfil\cr$\mkern 2.4mu\rightarrow$}}
  \def\bij@sym{\ooalign{$\rightarrowtail$\hfil\cr$\mkern 2.4mu\rightarrow$}}
  %
  \def\rel{\mathbin{\simple@enlarge{\leftrightarrow}}}
  \def\fun{\mathbin{\simple@enlarge{\rightarrow}}}
  \def\inj{\mathbin{\simple@enlarge{\rightarrowtail}}}
  \def\surj{\mathbin{\simple@enlarge{\surj@sym}}}
  \def\bij{\mathbin{\simple@enlarge{\bij@sym}}}
  \def\pinj{\mathbin{\simple@enlarge{\pinj@sym}}}
  \def\pfun{\mathbin{\simple@enlarge{\@p\rightarrow}}}
  \def\psurj{\mathbin{\simple@enlarge{\@p\surj@sym}}}
  \def\pbij{\mathbin{\simple@enlarge{\@p\bij@sym}}}
  \def\ffun{\mathbin{\simple@enlarge{\@f\rightarrow}}}
  \def\finj{\mathbin{\simple@enlarge{\@f\rightarrowtail}}}
  %
  \let\mapsto@sym\mapsto
  \def\mapsto{\mathbin{\simple@enlarge{\mapsto@sym}}}
  % 
  \def\comp@sym{\raise 0.6ex\hbox{\oalign{\hfil%
        $\scriptscriptstyle\mathtt{o}$\hfil%
        \cr\hfil$\scriptscriptstyle\mathtt{9}$\hfil}}}
  \def\lbag@sym{\ldbrack}
  \def\rbag@sym{\rdbrack}
  \def\extract@sym{\simple@enlarge{\upharpoonleft}}
  \def\project@sym{\simple@enlarge{\upharpoonright}}
  \let\dres@sym\vartriangleleft
  \let\rres@sym\vartriangleright
  \DeclareMathSymbol{\ndres@sym}{\mathbin}{arrows}{17}
  \DeclareMathSymbol{\nrres@sym}{\mathbin}{arrows}{18}
  \def\cat@sym{\smash{\raise 0.8ex\hbox{$\smallfrown$}}}
  \def\inv@sym{^{\simple@enlarge{\sim}}}
  \def\inbag@sym{\rlap{\hbox{$-$}}{\sqsubset}}
\fi

% -- mathematical notation ---------------------------------------------

\def\ELSE{\mathrel{\mathbf{else}}}
\def\IF{{\mathbf{if}}\;}
\def\IN{{\mathbf{in}}\;}
\def\LET{{\mathbf{let}}\;}
\def\THEN{\mathrel{\mathbf{then}}}
\def\bag{\mathop{\mathrm{bag}}}
\def\bcount{\mathbin{\sharp}}
\def\cat{\mathbin{\cat@sym}}
\def\comp{\mathrel{\comp@sym}}
\def\cross{\mathrel{\times}}
\def\dcat{\mathop{\cat/}}
\def\defs{\mathrel{\widehat=}}
\def\disjoint{{\mathsf{disjoint}}\;}
\def\div{\mathbin{\mathsf{div}}}
\def\dom{\mathop{\mathrm{dom}}}
\def\dres{\mathbin{\dres@sym}}
\def\exists{\strut@op{\exists@sym}}
\def\extract{\mathrel{\extract@sym}} 
\def\filter{\mathbin{\project}}
\def\finset{\strut@op{{\mathbb{F}}}}
\def\forall{\strut@op{\forall@sym}}
\def\hide{\mathrel{\backslash}}
\def\id{\mathop{\mathrm{id}}}
\def\iff{\mathrel{\Leftrightarrow}}
\def\zimplies{\mathrel{\Rightarrow}}
\def\inbag{\mathrel{\inbag@sym}}
\def\inseq{\mathrel{\mathsf{in}}}
\def\inv{^{\inv@sym}}
\def\iseq{\mathop{\mathrm{iseq}}}
\def\lambda{\strut@op{\lambda@sym}}
\def\land{\mathrel{\wedge}}
\def\lbag{\lbag@sym}
\def\lblot{{\langle}\mkern -3.5mu{|}}
\let\lbind\lblot
\def\ldata{\langle\!\langle}
\def\limg{(\mskip-4.5mu|}
\def\lnot{\neg\;}
\def\lor{\mathrel{\vee}}
\def\zmod{\mathbin{\mathsf{mod}}}
\def\mu{\strut@op{\mu@sym}}
\def\nat{{\mathbb{N}}}
\def\ndres{\mathbin{\ndres@sym}}
\def\nrres{\mathbin{\nrres@sym}}
\def\num{{\mathbb{Z}}}
\def\partition{\mathrel{\mathsf{partition}}}
\def\pipe{\mathord>\!\!\mathord>}
\def\plus{^+}
\def\power{\strut@op{\mathbb{P}}}
\def\prefix{\mathrel{\mathsf{prefix}}}
\def\pre{{\mathrm{pre}}\;}
\def\project{\mathrel{\project@sym}}
\def\ran{\mathop{\mathrm{ran}}}
\def\rbag{\rbag@sym}
\def\rblot{{|}\mkern -3.5mu{\rangle}}
\let\rbind\rblot
\def\rdata{\rangle\!\rangle}
\def\rimg{|\mskip-4.5mu)}
\def\rres{\mathbin{\rres@sym}}
\def\semi{\mathrel{\comp}}
\def\seq{\mathop{\mathrm{seq}}}
\def\shows{\mathrel{\vdash}}
\def\star{^*}
\def\subbageq{\mathrel{\sqsubseteq}}
\def\suffix{\mathrel{\mathsf{suffix}}}
\def\uminus{\mathrel{\uminus@sym}}
\def\upto{\mathbin{\ldotp\ldotp}}

% -- zed syntax --------------------------------------------------------

% any conditional _must_ be declared

\newif\ifzt@p           \zt@pfalse

\if@zedsyntax@

\def\bsup#1 \esup{^{#1}}
\def\inrel#1{\mathrel{\underline{#1}}}

\newdimen\zedindent \zedindent=\leftmargini%
\newdimen\zedleftsep \zedleftsep=1em%
\newdimen\zedtab \zedtab=2em%
\newdimen\zedbar \zedbar=6em%
\newskip\zedskip \zedskip=0.5\baselineskip plus0.333333\baselineskip% 
                                minus0.333333\baselineskip%
\def\zedsize{}%

\newcount\interzedlinepenalty \interzedlinepenalty=10000%
\newcount\preboxpenalty \preboxpenalty=0%

\def\@jot{0.5\zedskip}

\def\@narrow{\advance\linewidth by-\zedindent}

\def\@zrulefill{\leaders\hrule height\arrayrulewidth\hfill}

\def\@topline#1{\hbox to\linewidth{%
    \color{ZedBoxColor}%
    \vrule height\arrayrulewidth width\arrayrulewidth
    \vrule height0pt depth\@jot width0pt
    \hbox to\zedleftsep{\@zrulefill\thinspace}%
    {\color{ZedColor}#1}\thinspace\@zrulefill}}

\def\@zedline{\omit\hbox to 0pt{\color{ZedBoxColor}\vrule
    height\arrayrulewidth width\linewidth\hss} \cr}

\def\where{\@zskip\@jot
  \omit\hbox{\color{ZedBoxColor}\vrule height\arrayrulewidth width\zedbar} \cr
  \@zskip\@jot}

\def\also{\crcr \noalign{\penalty\interdisplaylinepenalty
    \vskip\zedskip}} 
\def\@zskip#1{\crcr \omit \hbox{\color{ZedBoxColor}\vrule height#1
    width\arrayrulewidth} \cr} 
\def\@zlign{\tabskip\z@skip\everycr{}} 

\let\tie=\t
\def\t#1{\afterassignment\@t\count@=#1}
\def\@t{\hskip\count@\zedtab}

\def\@setzsize{\let\next=\@nomath\def\@nomath##1{}%
  \skip0=\abovedisplayskip\skip1=\belowdisplayskip
  \zedsize \let\@nomath=\next 
  \abovedisplayskip=\skip0\belowdisplayskip=\skip1}

\def\@zed{\ifvmode\@zleavevmode\fi%
  $$\global\zt@ptrue
  \@setzsize
  \advance\linewidth by-\zedindent
  \advance\displayindent by\zedindent
  \def\\{\crcr}% Must have \def and not \let for nested alignments.
  \let\par=\relax
  \tabskip=0pt}

\def\zed{%
  \@zed\@znoskip\halign to\linewidth\bgroup%
  {\strut$\color{ZedColor}\@zlign##$}\hfil\tabskip=0pt
  plus1fil\cr}%  
\def\endzed{\crcr\egroup$$\global\@ignoretrue}

\def\@znoskip{%
  \offinterlineskip
  \everycr={%
    \noalign{%
      \ifzt@p\relax\global\zt@pfalse%
        \ifdim\prevdepth>-1000pt\relax%
          \skip0=\normalbaselineskip%
          \advance\skip0by-\prevdepth%
          \advance\skip0by-\ht\strutbox%
          \ifdim\skip0<\normallineskiplimit\relax%
            \vskip\normallineskip%
          \else%
            \vskip\skip0%
          \fi%
        \fi%
      \else%
        \penalty\interzedlinepenalty%
      \fi%
      }}}

\def\[{\begingroup\zed}
\def\]{\crcr\egroup$$\endgroup\ignorespaces}

\def\axdef{\def\also{\@zskip\zedskip}%
  \predisplaypenalty=\preboxpenalty%
  \@zed\@znoskip%
  \halign to\linewidth\bgroup%
    \strut{\color{ZedBoxColor}\vrule width\arrayrulewidth}\hskip\zedleftsep%
    {$\color{ZedColor}\@zlign##$}\hfil \tabskip=0pt plus1fil\cr}
\let\endaxdef=\endzed

\def\schema#1{\@ifnextchar[{\@schema{#1}}{\@nschema{#1}}}
\def\@schema#1[#2]{\@nschema{#1[#2]}}
\def\@nschema#1{\@narrow\axdef\omit\@topline{$\strut#1$}\cr}
\def\endschema{\@zskip\@jot\@zedline\endzed}

\@namedef{schema*}{\@narrow\axdef\@zedline\@zskip\@jot}
\expandafter\let\csname endschema*\endcsname=\endschema

\def\gendef{\@ifnextchar[{\@gendef}{\@ngendef}}
\def\@gendef[#1]{\@narrow\axdef\omit \setbox0=\hbox{$\strut[#1]$}%
  \rlap{\raise\doublerulesep\@topline{\hskip\wd0}}\@topline{\box0}\cr}
\def\@ngendef{\@narrow\axdef \@zedline \omit \hbox to\linewidth{\vrule
    height\doublerulesep width\arrayrulewidth \@zrulefill}\cr
  \@zskip\@jot
  } 
\let\endgendef=\endschema

\def\argue{%
  \@zed\interzedlinepenalty=\interdisplaylinepenalty
  \openup\@jot \halign to\linewidth\bgroup
  \strut%
  $\color{ZedColor}\@zlign##$\hfil \tabskip=0pt plus1fil
  &\hbox to0pt{%
    \color{AnnotationColor}\hss[\@zlign##\unskip]}\tabskip=0pt\cr%
  \noalign{\vskip-\@jot}}
\let\endargue=\endzed

\def\zbecause#1{\noalign{\vskip-\jot}&{\color{AnnotationColor}#1}\cr}

\def\syntax{\@zed\@znoskip \halign\bgroup
  \strut$\color{ZedColor}\@zlign##$\hfil
  &\hfil$\color{ZedColor}\@zlign{}##{}$\hfil 
  &$\color{ZedColor}\@zlign##$\hfil\cr}
\let\endsyntax=\endzed

\def\infrule{\@zed\@znoskip \halign\bgroup
  \strut\quad$\color{ZedColor}\@zlign##$\quad\hfil&\quad\@zlign##\hfil\cr}
\let\endinfrule=\endzed

\def\derive{\crcr \noalign{\vskip\@jot} \omit\@zrulefill
  \@ifnextchar[{\@xderive}{\@yderive}}
\def\@xderive[#1]{%
  &$\smash{%
    \lower 0.5ex\hbox{%
      \color{AnnotationColor}$[\;#1\;]$}}$\cr\noalign{\vskip\@jot}}
\def\@yderive{\cr \noalign{\vskip\@jot}}

\def\@zleavevmode{\if@inlabel \indent
  \else\if@noskipsec \indent
  \else\if@nobreak \global\@nobreakfalse
  \everypar={}\abovedisplayskip=0pt\fi
  {\parskip=0pt\noindent}\fi\fi}

\fi

% finally, block

\def\block{\@ifnextchar[{\@block}{\@block[t]}}
\def\@block[#1]{\array[#1]{@{}l@{}}}
\let\endblock=\endarray

\endinput