Re: extra math symbols and alignment

[Aditya Mahajan <adityam@umich.edu>]

Hi Wim,

Quoting WN <wneimeijer@tiscali.nl>:

> I tried your code and performed more tests. My first tests show your fix
> works. But than I added a \section{} in my test code and I am sorry 
> to say that
> the math matrix alignment does not work at that point.

:-) Section modifies \!!counta so things get messed up again. Actually, 
this really helped to narrow down the bug. Basically, dostartmatrix 
does a test

\scratchcounter=\ifnum\eqaligncolumn>\scratchcounter \eqaligncolumn 
\else \plusone \fi

which is comparing eqaligncolmn with scratch counter, but 
scratchcounter is never initialized. Therefore, everything depends on 
what was the value of scratchcounter, which explains, different 
behaviour depending on when the matrix  occurred, and why you had a 
hard time pinning down a minimal example.

The fix is easy, change the scratchcounter to zerocount (or maybe just 
change to \ifcase\eqaligncolunm). So add this to your file,

\unprotect
\def\dostartmathmatrix[#1][#2]%
  {\begingroup
   \edef\currentmathmatrix{#1}%
   \doifassignmentelse{#2}{\setupmathmatrix[#1][#2]}\donothing
   \null
   
\executeifdefined{\??mx:\mathmatrixparameter\c!location}{\getvalue{\??mx:\v!lohi}}%
   \mathmatrixleft
   \mathmatrixbox\bgroup
   \pushmacro\domatrixNC
   \let\endmath\relax
   \def\NC{\domatrixNC}%
   \def\MC{\domatrixNC\ifmmode\else$\def\endmath{$}\fi}%
   \global\let\domatrixNC\dodomatrixNC
   \def\NR{\endmath\global\let\domatrixNC\dodomatrixNC\crcr}%
   \normalbaselines
   \mathsurround\zeropoint
   \everycr\emptytoks
   \tabskip\zeropoint
   \eqaligncolumn\zerocount 
\processcommacommand[\mathmatrixparameter\c!align]{\advance\eqaligncolumn\plusone\dosetmatrixcolumn}%
   \scratchcounter=\ifnum\eqaligncolumn>\zerocount \eqaligncolumn \else 
\plusone \fi
   \global\eqaligncolumn\plusone
   \preparemathmatrix } % uses scratchcounter
\protect


Aditya
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