%  equation.cd
%  Anders G S Svensson

%  Source: equation.nw
%          $Revision: 1.17 $
%          $Date: 1996/02/19 22:40:12 $

\usecarrot{label}

\def\equation@cases@begin@{%
   \left\{\,\vcenter\bgroup \let\\\cr \normalbaselines \m@th
   \ialign\bgroup $##\hfil$&\quad##\hfil\crcr}
\def\equation@cases@end@{\crcr\egroup\egroup\right.}
\def\equation@eqalign@select@[#1]{%
   \@ifundefined@{equation@vbox@#1@}%
      {\@Warning@{Invalid eqalign option: #1}\equation@vbox@c@}%
      {\@cs@{equation@vbox@#1@}}%
   \bgroup
   \let\\\cr
   \openup\jot\m@th
   \ialign\bgroup
      \strut\hfil$\displaystyle{##}$
      &$\displaystyle{{}##}$\hfil\crcr}
\let\equation@vbox@t@\vtop
\let\equation@vbox@b@\vbox
\let\equation@vbox@c@\vcenter

\def\equation@eqalign@begin@{%
   \,\@ifnextchar@[\equation@eqalign@select@{\equation@eqalign@select@[c]}}
\def\equation@eqalign@end@{\crcr\egroup\egroup\,}
\def\equation@matrix@select@[#1]{%
   \vcenter\bgroup\let\\\cr
   \@ifundefined@{equation@lhfil@#1@}%
      {\@Warning@{Invalid matrix option: #1}
       \@let@{equation@lhfil@#1@}\hfil \@let@{equation@rhfil@#1@}\hfil}
      {}
   \normalbaselines\m@th
   \ialign\bgroup
      \@cs@{equation@lhfil@#1@}$##$\@cs@{equation@rhfil@#1@}&&\quad
         \@cs@{equation@lhfil@#1@}$##$\@cs@{equation@rhfil@#1@}\crcr
      \mathstrut\crcr\noalign{\kern-\baselineskip}}
\let\equation@lhfil@l@\relax \let\equation@rhfil@l@\hfil
\let\equation@lhfil@c@\hfil  \let\equation@rhfil@c@\hfil
\let\equation@lhfil@r@\hfil  \let\equation@rhfil@r@\relax

\def\equation@matrix@begin@{%
   \,\@ifnextchar@[\equation@matrix@select@{\equation@matrix@select@[c]}}
\def\equation@matrix@end@{%
   \crcr\mathstrut\crcr
   \noalign{\kern-\baselineskip}\egroup\egroup\,}
\def\pmatrixdelimiters#1#2{%
   \def\equation@pmatrixdelimiter@left@{#1}%
   \def\equation@pmatrixdelimiter@right@{#2}}
\pmatrixdelimiters()
\def\equation@displaymath@begin@{%
   \@ifmmode@
      {\let\equation@displaymath@end@\relax}%
      {$$\def\equation@displaymath@end@{$$}}}

\def\equation@align@displaymath@begin@{\equation@displaymath@begin@}
\def\equation@align@displaymath@end@{\equation@displaymath@end@}

\def\equation@equation@begin@{%
   \equation@insertifstarred@\equation@equation@nonumber@
      \equation@equation@begin@primitive@}

\def\equation@equation@end@{%
   \equation@stepcounter@\currentcounter
   \equation@eqno@\equation@number@ \equation@equation@label@
   \equation@displaymath@end@\@ignorespaces@}
\def\equation@equation@begin@primitive@#1{%
   \equation@displaymath@begin@
   #1\equation@equation@numbering@
   \def\equation@align@displaymath@begin@{%
      \def\equation@align@displaymath@end@{\egroup$\hss\egroup}%
      \hbox to\z@\bgroup
         \hss$\vcenter\bgroup
         \equation@align@nonumbers@ \let\equation@tagcr@\crcr}}

\def\equation@insertifstarred@#1#2{#2\relax}
\let\equation@stepcounter@\@eat@
\def\equation@equation@nonumber@{%
   \let\equation@eqnobox@choice@\@eattwo@}
\def\rightequationtags{%
   \def\equation@eqno@{\equation@eqnobox@choice@\eqno}%
   \let\equation@tagbox@\equation@tagbox@right@}

\def\leftequationtags{%
   \def\equation@eqno@{\equation@eqnobox@choice@\leqno}%
   \let\equation@tagbox@\equation@tagbox@left@}

\def\equation@tagbox@left@#1{\hbox to \displaywidth{#1\hss}}
\def\equation@tagbox@right@#1{#1}

\rightequationtags

\let\equation@eqnobox@choice@\@eattwo@
\def\equation@eqnobox@#1#2{#1{\hbox{#2}}}
\def\equation@equation@label@{\equation@equation@label@primitive@}
\let\equation@equation@label@primitive@\relax

\def\equation@label@generate@{\@warning@{Missing \tag}\@eat@}

\def\equation@equation@numbering@{%
   \def\label##1{%
      \def\equation@equation@label@primitive@{%
         \equation@label@generate@{##1}}}%
   \let\tag\equation@equation@tag@
   \def\notag{%
      \let\equation@eqno@\@eat@ \let\equation@equation@label@\relax}}

\def\equation@equation@tag@{%
   \let\equation@eqnobox@choice@\equation@eqnobox@
   \@ifnextchar@*%
      {\expandafter\equation@equation@tag@star@\@eat@}
      \equation@equation@tag@nostar@}
\def\equation@equation@tag@star@#1{%
   \def\equation@number@{#1}%
   \def\equation@label@generate@##1{\definexr{##1}{#1}{empty}}}

\def\equation@equation@tag@nostar@#1{%
   \def\equation@number@{\@cs@{\currentcounter tag}{#1}}%
   \def\equation@label@generate@##1{\definexr{##1}{#1}\currentcounter}}
\def\equation@display@begin@{%
   \equation@insertifstarred@\equation@align@nonumbers@
      \equation@display@begin@primitive@}

\def\equation@display@end@{%
   \equation@crcr@ \egroup \equation@align@displaymath@end@\@ignorespaces@}

\def\equation@display@begin@primitive@#1{%
   \equation@align@displaymath@begin@
   #1\equation@align@numbering@
   \displ@y \tabskip\z@skip
   \halign\bgroup
      &{\gdef\equation@crcr@{\equation@cr@}}%
       \hbox to\displaywidth{$\@lign\hfil\displaystyle##\hfil$}\crcr}
\def\equation@subdisplay@begin@{%
   \equation@insertifstarred@\equation@align@nonumbers@
      \equation@subdisplay@begin@primitive@}

\def\equation@subalign@numbering@{%
   \def\equation@number@{\subequationtag\thesubequation}%
   \def\currentcounter{subequation}%
   \equation@tweaknumbering@
   \equation@align@numbering@primitive@}

\let\equation@tweaknumbering@\relax

\def\equation@subdisplay@begin@primitive@#1{%
   \equation@display@begin@primitive@{#1\equation@subalign@numbering@\@eat@}}
\def\equation@align@begin@{%
   \equation@insertifstarred@\equation@align@nonumbers@
      \equation@align@begin@primitive@}

\def\equation@align@end@{%
   \equation@crcr@ \egroup \equation@align@displaymath@end@\@ignorespaces@}

\def\equation@align@begin@primitive@#1{%
   \equation@align@displaymath@begin@
   #1\equation@align@numbering@
   \displ@y \tabskip\centering
   \halign to\displaywidth\bgroup
      &{\gdef\equation@crcr@{\equation@cr@}}%
       \hfil$\@lign\displaystyle{##}$\tabskip\z@skip
      &$\@lign\displaystyle{{}##}$\hfil\tabskip\centering\crcr}
\def\equation@subalign@begin@{%
   \equation@insertifstarred@\equation@align@nonumbers@
      \equation@subalign@begin@primitive@}

\def\equation@subalign@begin@primitive@#1{%
   \equation@align@begin@primitive@{#1\equation@subalign@numbering@\@eat@}}
\def\equation@align@numbering@primitive@{%
   \def\\{\equation@cr@}%
   \global\let\equation@align@label@\relax
   \global\let\equation@align@label@generate@\equation@label@generate@
   \def\label##1{%
      \gdef\equation@align@label@{\equation@align@label@generate@{##1}}}%
   \let\tag\equation@align@tag@ \let\notag\equation@align@notag@}
\def\equation@align@numbering@{%
   \def\currentcounter{equation}%
   \equation@align@numbering@primitive@}

\def\equation@align@nonumbers@{%
   \def\equation@cr@{\crcr}\def\equation@crcr@{\crcr}}%
\let\equation@align@notag@\equation@align@nonumbers@
\def\equation@align@tag@{\relax
   \def\equation@cr@{\equation@tagcr@}%
   \gdef\equation@crcr@{\equation@tagcr@}%
   \@ifnextchar@*%
      {\expandafter\equation@align@tag@star@\@eat@}%
      \equation@align@tag@nostar@}

\def\equation@align@tag@star@#1{%
   \equation@align@buildtab@\@echo@{#1}%
   \gdef\equation@align@label@generate@##1{\definexr{##1}{#1}{empty}}}
\def\equation@align@tag@nostar@#1{%
   \equation@align@buildtab@{\@cs@{\currentcounter tag}}{#1}%
   \gdef\equation@align@label@generate@##1{\definexr{##1}{#1}\currentcounter}}

\def\equation@tagcr@{%
   \equation@numbertab@tag@ \crcr
   \noalign{%
      \equation@align@label@
      \global\let\equation@align@label@\relax
      \global\let\equation@align@label@generate@\@eat@
      \gdef\equation@crcr@{\crcr}}}

\def\equation@align@buildtab@#1#2{%
    \gdef\equation@numbertab@tag@{&\omit \llap{\equation@tagbox@{#1{#2}}}}}

\let\equation@crcr@\crcr \let\equation@cr@\crcr
\let\equation@autocr@\crcr
\def\equationtag#1{(#1)}
\let\subequationtag\equationtag

\DeclareOption{number}
   {\usecarrot{counter}
    \newcounter{equation}
    \newcounter{subequation}[equation]
    \def\thesubequation{\theequation\alph{subequation}}
    \def\equation@insertifstarred@#1#2{\@ifnextchar@*{\@eatnextchar@{#2#1}}{#2\relax}}
    \let\equation@stepcounter@\stepcounter
    \let\equation@eqnobox@choice@\equation@eqnobox@
    \def\equation@number@{\equationtag\theequation}
    \def\equation@equation@nonumber@{%
       \let\equation@eqnobox@choice@\@eattwo@
       \let\equation@stepcounter@\@eat@}
    \def\equation@label@generate@#1{\definelabel{#1}\currentcounter}
    \def\equation@equation@numbering@{%
       \def\currentcounter{equation}%
       \def\label##1{%
          \def\equation@equation@label@primitive@{%
             \equation@label@generate@{##1}}}%
       \let\tag\equation@equation@tag@
       \let\notag\equation@equation@notag@}
    \def\equation@equation@tag@{\relax
       \let\equation@stepcounter@\@eat@
       \@ifnextchar@*%
          {\expandafter\equation@equation@tag@star@\@eat@}
          \equation@equation@tag@nostar@}
    \def\equation@equation@notag@{%
       \let\equation@eqno@\@eat@ \let\equation@equation@tag@\relax
       \let\equation@stepcounter@\@eat@}
    \def\equation@tweaknumbering@{%
       \@def@{counter@ctr++@subequation}{%
          \stepcounter{equation}%
          \counter@stepcounter@{subequation}%
          \@gdef@{counter@ctr++@subequation}{%
             \counter@stepcounter@{subequation}}}}%
    \def\equation@autocr@{%
       \stepcounter\currentcounter
       \equation@align@label@ \equation@numbertab@ \crcr
       \noalign{%
          \global\let\equation@align@label@\relax
          \global\let\equation@align@label@generate@\equation@label@generate@
          \gdef\equation@crcr@{\crcr}}}
    \let\equation@cr@\equation@autocr@
    \def\equation@numbertab@{&\omit \llap{\equation@tagbox@\equation@number@}}}

\DeclareOption{arg}
   {\def\cases#1{\equation@cases@begin@ #1\equation@cases@end@}
    \def\equation@eqalign@arg@[#1]#2{%
       \,\equation@eqalign@select@[#1]#2\equation@eqalign@end@}
    \def\eqalign{\null
       \@ifnextchar@[\equation@eqalign@arg@{\equation@eqalign@arg@[c]}}
    \def\equation@matrix@arg@[#1]#2{%
       \,\equation@matrix@select@[#1]#2\equation@matrix@end@}
    \def\equation@pmatrix@arg@[#1]#2{%
       \left\equation@pmatrixdelimiter@left@
       \equation@matrix@arg@[#1]#2\equation@matrix@end@
       \right\rpmtxdel@\ignorespaces}
    \def\matrix{\null
       \@ifnextchar@[\equation@matrix@arg@{\equation@matrix@arg@[c]}}
    \def\pmatrix{\null
       \@ifnextchar@[\equation@pmatrix@arg@{\equation@pmatrix@arg@[c]}}
    \def\equation{%
       \equation@insertifstarred@\equation@equation@nonumber@
          \equation@equation@arg@}
    \def\equation@equation@arg@#1#2{%
       \equation@equation@begin@primitive@#1#2\equation@equation@end@}
    \def\display{%
       \equation@insertifstarred@\equation@align@nonumbers@
          \equation@display@arg@}
    \def\equation@display@arg@#1#2{%
       \equation@display@begin@primitive@#1#2\equation@display@end@}
    \def\subdisplay{%
       \equation@insertifstarred@\equation@align@nonumbers@
          \equation@subdisplay@arg@}
    \def\equation@subdisplay@arg@#1#2{%
       \equation@subdisplay@begin@primitive@#1#2\equation@display@end@}
    \def\align{%
       \equation@insertifstarred@\equation@align@nonumbers@\equation@align@arg@}
    \def\equation@align@arg@#1#2{%
       \equation@align@begin@primitive@#1#2\equation@align@end@}
    \def\subalign{%
       \equation@insertifstarred@\equation@align@nonumbers@
          \equation@subalign@arg@}
    \def\equation@subalign@arg@#1#2{%
       \equation@subalign@begin@primitive@#1#2\equation@align@end@}}

\DeclareOption{block}
   {\usecarrot{environ}
    \newpair*{cases}{\equation@cases@begin@}{\equation@cases@end@}
    \newpair*{eqalign}{\null\equation@eqalign@begin@}{\equation@eqalign@end@}
    \newpair*{matrix}{\null\equation@matrix@begin@}{\equation@matrix@end@}
    \newpair*{pmatrix}
       {\left\equation@pmatrixdelimiter@left@ \equation@matrix@begin@}
       {\equation@matrix@end@ \right\equation@pmatrixdelimiter@right@}
    \newpair*{equation}{\equation@equation@begin@}{\equation@equation@end@}
    \newpair*{display}{\equation@display@begin@}{\equation@display@end@}
    \newpair*{subdisplay}{\equation@subdisplay@begin@}{\equation@display@end@}
    \newpair*{align}{\equation@align@begin@}{\equation@align@end@}
    \newpair*{subalign}{\equation@subalign@begin@}{\equation@align@end@}}

\DeclareOption{environ}
   {\usecarrot{environ}
    \newpair{cases}{\equation@cases@begin@}{\equation@cases@end@}
    \newpair{eqalign}{\null\equation@eqalign@begin@}{\equation@eqalign@end@}
    \newpair{matrix}{\null\equation@matrix@begin@}{\equation@matrix@end@}
    \newpair{pmatrix}
       {\left\equation@pmatrixdelimiter@left@ \equation@matrix@begin@}
       {\equation@matrix@end@\right\equation@pmatrixdelimiter@right@}
    \newpair{equation}{\equation@equation@begin@}{\equation@equation@end@}
    \newpair{display}{\equation@display@begin@}{\equation@display@end@}
    \newpair{subdisplay}{\equation@subdisplay@begin@}{\equation@display@end@}
    \newpair{align}{\equation@align@begin@}{\equation@align@end@}
    \newpair{subalign}{\equation@subalign@begin@}{\equation@align@end@}}

\IfOption{arg}{}{\IfOption{block}{}{\Option{environ}}}

\def\intertext#1{\noalign{#1}}