I’have a lot of courses notes in MKII. I’m trying to move to MKIV. I have a problem that I’m not able to resolve, to make a border matrix with brackets. In MKII, I was using a macro, found somewhere, which works great, but no longer works; here is the macro:

% Border matrix: first line and column are label
\font\tenex=cmex10 \setbox0=\hbox{\tenex B} \p@renwd=\wd0
\def\bbordermatrix#1{\begingroup \m@th

but MKIV gives me the error:

\bbordermatrix #1->\begingroup \m@th 

                                     \setbox \z@ \vbox {\def \cr {\crcr \noa...

l.26    i & j & k & l \cr}


16       \null\;\vbox{\kern\ht\@ne\box\tw@}\endgroup}

17     \catcode`\@=12\relax

I look for solutions on the list, but did not find anything.Here is a minimal example:

A border matrix:
   a & b & c & d \cr
   e & f & G & h \cr
   i & j & k & l \cr}

As I have in my notes hundreds of such matrix, it is really difficult to change the input format.

Do you know, or can you point me, to a solution ? I’m in a dead end..  Thanks a lot.