%%% ====================================================================
%%%  @LaTeX-style-file{
%%%     author          = "Enrico Bertolazzi",
%%%     version         = "0.6",
%%%     date            = "23-SEPT-1996",
%%%     filename        = "easyeqn.sty",
%%%     address         = "Laboratorio di Matematica Applicata
%%%                        Trento University,
%%%                        Via Mesiano, Trento, Italy",
%%%     FAX             = "+39 (461) 882672",
%%%     email           = "bertolaz@ing.unitn.it (Internet)",
%%%     supported       = "yes. Please send comments via E-mail",
%%%     docstring       = "package for easy typing equations.
%%%
%%% INSTALLATION:
%%%   Put this file where your TeX looks for inputs.
%%%
%%% DOCUMENTATION:
%%%  Compile doceqn.tex.
%%%
%%% COPYING:
%%%   Copying of part or all of this file is allowed under the following
%%%   conditions only:
%%%   (1) You may freely distribute unchanged copies of the file. Please
%%%       include the documentation when you do so.
%%%   (2) You may modify a renamed copy of the file, but only for personal
%%%       use or use within an organization.
%%%   (3) You may copy fragments from the file, for personal use or for
%%%       distribution, as long as credit is given where credit is due.
%%%
%%%   You are NOT ALLOWED to take money for the distribution or use of
%%%   this file or modified versions or fragments thereof, except for
%%%   a nominal charge for copying etc.
%%%
%%%  }
%%%
%%% v 0.2 15/may/96 first release
%%% v 0.3 27/july/96
%%%       addedd fleq, leqno options
%%%       EQA environment
%%%       \numberright and \equationcenter commands
%%%       improved \label command
%%% v 0.4 improved tracing algorithm
%%% v 0.5 improved spacing in the formulae, added cosmetic commands
%%% v 0.6 correct label alignment in single equation
%%% ====================================================================
%%%       ___    ____  ___   _   _      __    __    ____ ______
%%%      /   \  /     /   \  \  /      /  \  /  \  /       /
%%%     /____/ /__   /____/   \/       \    /   / /__     /
%%%    /   \  /     /  \      /         \  /   / /       /
%%%   /____/ /____ /    \    /       \__/  \__/ /       /
%%% ====================================================================
\typeout{Document Style `easyeqn' version 0.6 <23-SEPT-1996>.}
%% BEGIN easyeqn.sty
%%
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{easyeqn}[1996/09/23 v0.6]

\let\@EQ@alleqnum\iffalse
\let\if@EQ@warning\iffalse

\def\equationcenter{\gdef\@EQ@indent{\tabskip\@centering}}%
\def\equationleft{\gdef\@EQ@indent{\tabskip\@EQ@leftmargin}}%

\def\eqspacing#1{\xdef\@EQ@surround{#1\noexpand\relax}}
\def\eqcolumnsep#1{\@tempdima=#1\divide\@tempdima2\xdef\@EQ@colsep{\noexpand\hskip\the\@tempdima}}
\def\eqleftmargin#1{\xdef\@EQ@leftmargin{#1\noexpand\relax}}
\def\eqrowsep#1{\xdef\@EQ@rowsep{\noexpand\penalty\noexpand\@M\noexpand\vskip#1}}

\eqspacing{6pt}
\eqcolumnsep{2pt}
\eqleftmargin\leftmargini
\eqrowsep{7pt}

\def\@EQ@NUM@LEFT{\llap{\hb@xt@\displaywidth{\@@eqnnum\hss}}}
\def\@EQ@NUM@RIGHT{\llap{\@@eqnnum}}

\def\numberleft{\global\let\@EQ@N@NUM\@EQ@NUM@LEFT}
\def\numberright{\global\let\@EQ@N@NUM\@EQ@NUM@RIGHT}

\DeclareOption{allnumber}{\global\let\@EQ@alleqnum\iftrue}
\DeclareOption{warning}{\global\let\if@EQ@warning\iftrue}
\DeclareOption{fleqn}{\equationleft}
\DeclareOption{leqno}{\numberleft}

\numberright
\equationcenter

\ProcessOptions

\input{easy.sty}

\if@EQ@warning
   \newcounter{@EQ@level}
   \setcounter{@EQ@level}{1}
   \xdef\@EQ@file@inputi{\jobname.tex}
   \xdef\@EQ@file@input{\jobname.tex}
   \global\let\@EQ@old@input\input
   \gdef\@EQ@input@shade{%
       \@ifnextchar\bgroup{\@EQ@input}{%
       \PackageWarning{`easyeqn'}%
       {you must use \string\input\space with braces for correct cross 
       referencing}\@EQ@old@input}%
   }
   \gdef\@EQ@input#1{%
       \addtocounter{@EQ@level}{\@ne}
       \expandafter\xdef\csname @EQ@file@input\roman{@EQ@level}\endcsname{#1}
       \xdef\@EQ@file@input{\csname @EQ@file@input\roman{@EQ@level}\endcsname}
       \@EQ@old@input{#1}%
       \addtocounter{@EQ@level}{\m@ne}
       \xdef\@EQ@file@input{\csname @EQ@file@input\roman{@EQ@level}\endcsname}
   }
   \global\let\@EQ@old@input\input%
   \AtEndDocument{\global\let\input\@EQ@old@input}%
   \AtBeginDocument{\global\let\input\@EQ@input@shade}%
\fi

\def\@EQ@write@warning#1{%
     \edef\@temp{\noexpand\AtEndDocument{\noexpand\PackageWarningNoLine{`easyeqn'}%
                {#1, in \@EQ@file@input\space line \the\inputlineno}}}%
     \@temp%
}
\def\@EQ@warning@label{%
    \PackageWarning{`easyeqn'}%
    {you must use \string\eqlabel\space instead of \string\label\space in EQx environments}
}
\def\@EQ@warning@nolabel{%
    \PackageWarning{`easyeqn'}%
    {\string\label\space and \string\eqlabel\space disabled in EQx* environments}
}
\let\@EQ@old@label\label

\def\eqlabel{\@ifnextchar[\@EQ@ll\@EQ@l}
\def\@EQ@l{\@ifnextchar(\@EQ@lll\@EQ@label}
\def\@EQ@ll[#1]#2{\@EQ@customlabel{#1}{#1}{#2}}
\def\@EQ@lll(#1)#2{\@EQ@customlabel{(#1)}{#1}{#2}}
\def\@EQ@customlabel#1#2#3{%
   \xdef\@@eqnnum{#1}\xdef\@currentlabel{#2}\@EQ@label{#3}
   \gdef\@currentlabel{\p@equation\theequation}}
\def\@EQ@label#1{%
  \@ifundefined{r@eq@#1}{%
     \if@EQ@warning\@EQ@write@warning{Label `#1' may be not referenced}\fi%
  }{\global\let\if@EQ@numbering\iftrue}%
  \if@EQ@numbering\@EQ@old@label{#1}\fi
}

\let\@@eqnnum\@eqnnum%
\def\@EQ@NUM{\if@EQ@numbering\@EQ@N@NUM%
\ifx\@@eqnnum\@eqnnum\stepcounter{equation}%no custom label
\else\global\let\@@eqnnum\@eqnnum\fi% custom label
\fi}

\def\@EQ@newreference#1{\expandafter\global\expandafter\let\csname r@eq@#1\endcsname\@empty}
\def\@EQ@addreference#1{\@bsphack\protected@write\@auxout{}{\string\@EQ@newreference{#1}}\@esphack}

\def\refeq#1{\protect\@EQ@addreference{#1}\ref{#1}}

\def\eqref#1{\textrm{(\refeq{#1})}}

\def\@EQ@CR{{\ifnum0=`}\fi\@EQ@CR@}
\def\@EQ@CR@{\@ifnextchar[\@EQ@CR@@{\@EQ@CR@@[\z@]}}
\def\@EQ@CR@@[#1]{\ifnum0=`{\fi}\crcr\noalign{\@EQ@rowsep\vskip#1\relax}}

\def\@EQ@NL{{\ifnum0=`}\fi\@EQ@NL@}
\def\@EQ@NL@{\@ifnextchar[\@EQ@NL@@{\@EQ@NL@@[\z@]}}
\def\@EQ@NL@@[#1]{\ifnum0=`{\fi}&\@EQ@NUM%
\global\let\if@EQ@numbering\@EQ@alleqnum\crcr\noalign{\@EQ@rowsep\vskip#1\relax}}

\def\yesnumber{\global\let\if@EQ@numbering\iftrue}

\long\def\eqbox{\@ifnextchar(\@eqbox{\@eqbox(.25pt,3pt)}}
\long\def\@eqbox(#1,#2)#3{\fboxrule#1\fboxsep#2\fbox{$\displaystyle#3$}}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Parser zone
\def\@EQ@addcol{\g@addto@macro\@EQ@bformat{\tabskip\z@skip\@EQ@colsep&\@EQ@colsep}}

\def\@EQ@parse{%
\gdef\@EQ@bformat{%
\everycr{}\@EQ@indent\halign to\displaywidth\bgroup}%
\global\let\@EQ@cmdadd\@empty\@EQ@parsea}

\def\@EQ@parsea{\futurelet\@tempb\@EQ@parseb}
\def\@EQ@parseb{\ifx\end\@tempb\def\next##1{}\else\let\next\@EQ@cmd\fi\next}%

\def\@EQ@cmd#1{%
\@EQ@cmdadd\global\let\@EQ@cmdadd\@EQ@addcol%
\ifx\@tempb l\else\g@addto@macro\@EQ@bformat{\hfil}\fi%
\g@addto@macro\@EQ@bformat{$\displaystyle##$}%
\ifx\@tempb r\else\g@addto@macro\@EQ@bformat{\hfil}\fi%
\@EQ@parsea}
  
\def\@EQ@ALIGN#1#2{\expandafter\@EQ@parse#1\end\let\\\@EQ@CR%
$$\abovedisplayskip=\@EQ@surround\belowdisplayskip=\@EQ@surround%
#2\bgroup\@EQ@bformat\tabskip\@centering\crcr}
\def\end@EQ@ALIGN{\crcr\egroup\egroup\@EQ@NUM$$\global\@ignoretrue} %

\def\@EQ@A@ALIGN#1{%
\expandafter\@EQ@parse#1\end\let\\\@EQ@NL%
$$\abovedisplayskip=\@EQ@surround\belowdisplayskip=\@EQ@surround%
\@EQ@bformat\tabskip\@centering&\tabskip\z@skip\hb@xt@\z@{\hss##}\crcr}
\def\end@EQ@A@ALIGN{&\@EQ@NUM\crcr\egroup$$\global\@ignoretrue}

\def\@EQ@NUMBER{\let\label\@EQ@warning@label\global\let\if@EQ@numbering\@EQ@alleqnum%
\gdef\@currentlabel{\p@equation\theequation}\addtocounter{equation}{\@ne}}
\def\end@EQ@NUMBER{\addtocounter{equation}{\m@ne}}

\def\@EQ@NO@NUMBER{\let\label\@EQ@warning@nolabel\let\eqlabel\@EQ@warning@nolabel}

%%%%%%%%%%%%%%%%%%%%% EQS %%%%%%%%%%%%%%%%%%%%%%%%%%
\def\EQS{\@ifnextchar[\@EQ@EQS{\@EQ@EQS[rl]}}
\def\@EQ@EQS[#1]{\@EQ@NUMBER\@EQ@ALIGN{#1}\vcenter}
\def\endEQS{\end@EQ@ALIGN\end@EQ@NUMBER}

\@namedef{EQS*}{\@ifnextchar[\@EQ@EQSS{\@EQ@EQSS[rl]}}
\def\@EQ@EQSS[#1]{\@EQ@NO@NUMBER\@EQ@ALIGN{#1}\vcenter}
\@namedef{endEQS*}{\end@EQ@ALIGN}

%%%%%%%%%%%%%%%%%%%%% EQA %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\def\EQA{\@ifnextchar[\@EQ@EQA{\@EQ@EQA[rcl]}}
\def\@EQ@EQA[#1]{\@EQ@NUMBER\@EQ@A@ALIGN{#1}}
\def\endEQA{\end@EQ@A@ALIGN\end@EQ@NUMBER}

%%%%%%%%%%%%%%%%%%%%% EQS %%%%%%%%%%%%%%%%%%%%%%%%%%
\def\EQ{\@EQ@NUMBER\@EQ@ALIGN{c}\vbox}
\let\endEQ\endEQS

\@namedef{EQ*}{\@EQ@NO@NUMBER\@EQ@ALIGN{c}\vbox}
\@namedef{endEQ*}{\end@EQ@ALIGN}

\endinput