\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{mdwtab1}[2007/02/05 Improved mdwtab by ccshan]
\RequirePackageWithOptions{mdwtab}

% Stop revtex4 from overriding array and tabular from mdwtab.
\ifx\undefined\class@documenthook\else
    \let\save@endtabular\endtabular
    \let\save@endarray  \endarray
    \let\save@@tabular  \@tabular
    \let\@tabular       \@tabular@array
    \let\switch@tabular \relax
    \let\switch@array   \relax
    \appdef\class@documenthook{%
    \let\endtabular\save@endtabular
    \let\endarray  \save@endarray
    \let\@tabular  \save@@tabular}%
\fi

% Typeset unboxed tabulars as display haligns and compatibly with tabularx.
\let\tab@setposn@\tab@setposn
% Intercept \tab@setposn defined by the mdwtab package, which takes
% a position-arg (one of [tcbLCR]) as argument.  Rename this original
% version of \tab@setposn to \tab@setposn@.
\def\tab@setposn#1{%
  % Set \if@tempswa to whether this tabular is unboxed.
  \@tempswafalse
  \if#1L\@tempswatrue\fi
  \if#1C\@tempswatrue\fi
  \if#1R\@tempswatrue\fi
  % Because we want an unboxed tabular to result in a display halign, stop
  % \tab@setposn@ from ending the current paragraph if the tabular is unboxed.
  \if@tempswa\let\par\@empty\fi
  % If we are in the trial phase for tabularx, then make a boxed rather than
  % unboxed tabular.
  \ifx\@footnotetext\TX@trial@ftn
    \ifx\undefined\measuring@true\else\measuring@true\fi
  \else
    \@tempswafalse
  \fi
  \if@tempswa\tab@setposn@{t}\else\tab@setposn@{#1}\fi
  % If we are actually making an unboxed tabular, then we need to override
  % \tab@setposn@'s setting of \tab@left and \tab@right (and \tab@initread's
  % setting of \tab@startpause and \tab@endpause) to make a display halign
  % instead.  We also change \tab@penalty to follow \interdisplaylinepenalty and
  % amsmath's \displaybreak.  Finally, we need to stop \@array from zeroing out
  % \lineskip and \baselineskip, and do it inside the display math instead, so
  % that the current paragraph's lines won't get all bunched together.
  \if@tempswa
    \def\dsp@penalty##1{% For \tab@right, \tab@startpause, \tab@penalty below
        \ifx\undefined\dspbrk@lvl ##1%
        \else \ifnum\dspbrk@lvl <\z@ ##1%
        \else -\@getpen\dspbrk@lvl \global\dspbrk@lvl\m@ne \fi\fi}%
    \def\tab@left{$$\displayindent\z@\lineskip\z@\baselineskip\z@
        \ifx\undefined\dspbrk@context \else \chardef\dspbrk@context\z@ \fi
        \ifx\undefined\dspbrk@lvl \else \global\dspbrk@lvl\m@ne \fi}%
    \def\tab@right{\postdisplaypenalty\dsp@penalty\postdisplaypenalty
        $$\global\@ignoretrue}%
    \def\tab@startpause{\penalty\dsp@penalty\postdisplaypenalty
        \vskip\belowdisplayskip}%
    \def\tab@endpause{\penalty\predisplaypenalty\vskip\abovedisplayskip}%
    \def\tab@penalty{\penalty\dsp@penalty\interdisplaylinepenalty}%
    \let\lineskip@save\lineskip
    \def\lineskip\z@\baselineskip\z@{\let\lineskip\lineskip@save}%
  \fi}