Re: displayed formula confuses parshape around figure

[Wolfgang Schuster <schuster.wolfgang@googlemail.com>]

On Wed, 20 Sep 2006 14:36:33 +0100
Sanjoy Mahajan <sanjoy@mrao.cam.ac.uk> wrote:

> > It works for me if put a \par or a empty line after the first
> > \input.
> 
> That's true, but doing so ends the paragraph.  Shouldn't the displayed
> math be part of the paragraph?  The \input tufte's were just to make
> the minimal example.  It came from a paragraph with text and math that
> begins with a figure:
> 
> \placefigure[right,none]{}{\externalfigure[dummy]}
> 
> Then lots of text about the figure, leading up to 
> \startformula
> this equation
> \stopformula
> then more text discussing the equation...
> 
> -Sanjoy
> 

Ok, I playes yesterday I bit with your example and can you give now
a solution for your problem.

\starttext

% This works

\hangindent4cm
\hangafter-3
\input tufte
$$
A = a^\alpha b^\beta,
$$
\input tufte

\blank[line]

% The group around the formula produces the error. I tried this also
% with plain TeX and I worked without problems. A ConTeXt bug.

\hangindent4cm
\hangafter-3
\input tufte
\bgroup
$$
A = a^\alpha b^\beta,
$$
\egroup
\input tufte

% Test if my path works also with intending

%\setupindenting[yes,medium]
%\setupformulas[indentnext=yes]

% Patch for startformula/s, look a hangindent and hangafter.

\unprotect

\def\dostopformula
  {\doplaceformulanumber
   \getvalue{\e!stop\formulaparameter\c!alternative\v!formula}%
   \resetlastlinewidth
   \nonoindentation
   \dochecknextindentation{\??fm\currentformula}%
   \egroup
   \hangafter\minusone   % added
   \hangindent\zeropoint % added
   \setfalse\handleformulanumber
   \dorechecknextindentation} % here ?

\def\startformulas#1\stopformulas % new / to be internationalized
  {\bgroup
   \forgetdisplayskips
   \startdisplaymath
   \setlocalhsize
   \long\def\startformula##1\stopformula{\advance\scratchcounter
\plusone}% \scratchcounter\zerocount #1% preroll
   \divide \hsize \scratchcounter
   \hbox to \localhsize \bgroup
     \hss
     \def\normalstartformula{\vskip-\strutdepth$$}% i hate this
     \def\normalstartformula{\vskip-\strutdepth$$}% i hate this
     \def\normalstopformula {$$}%
     \def\startformula{$\vcenter\bgroup\normalstartformula}%
     \def\stopformula {\normalstopformula\egroup$\hss}%
     #1%
     \egroup
   \stopdisplaymath
   \egroup
   \hangafter\minusone   % added
   \hangindent\zeropoint} % added

\protect

% No longer a problem, my patch works.

\hangindent4cm
\hangafter-3
\input tufte
\startformula
A = a^\alpha b^\beta,
\stopformula
\input tufte

\blank[line]

\hangindent4cm
\hangafter-3
\input tufte
\startformulas
\startformula
A = a^\alpha b^\beta,
\stopformula
\stopformulas
\input tufte

\stoptext

Wolfgang