Thanks so much !
I’ll will add an entry to the wiki.
Fabrice.


Le 28 août 2017 à 13:29:55, Hans Hagen (pragma@wxs.nl) a écrit:

On 8/28/2017 6:33 PM, Fabrice L wrote:
> Hi,
>
> 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
> \catcode`\@=11\relax
> \newdimen\p@renwd
> \font\tenex=cmex10 \setbox0=\hbox{\tenex B} \p@renwd=\wd0
> \def\bbordermatrix#1{\begingroup \m@th
> \setbox\z@\vbox{\def\cr{\crcr\noalign{\kern2\p@\global\let\cr\endline}}%
>     \ialign{$##$\hfil\kern2\p@\kern\p@renwd&\thinspace\hfil$##$\hfil
>       &&\quad\hfil$##$\hfil\crcr
>       \omit\strut\hfil\crcr\noalign{\kern-\baselineskip}%
>       #1\crcr\omit\strut\cr}}%
>   \setbox\tw@\vbox{\unvcopy\z@\global\setbox\@ne\lastbox}%
>   \setbox\tw@\hbox{\unhbox\@ne\unskip\global\setbox\@ne\lastbox}%
>   \setbox\tw@\hbox{$\kern\wd\@ne\kern-\p@renwd\left[\kern-\wd\@ne
>     \global\setbox\@ne\vbox{\box\@ne\kern2\p@}%
>     \vcenter{\kern-\ht\@ne\unvbox\z@\kern-\baselineskip}\,\right]$}%
>   \null\;\vbox{\kern\ht\@ne\box\tw@}\endgroup}
> \catcode`\@=12\relax

Such a plain macro needs to be made bodyfotn size aware and such.

> 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:
>
> \starttext
> A border matrix:
> \startformula
> \bbordermatrix{
>    a & b & c & d \cr
>    e & f & G & h \cr
>    i & j & k & l \cr}
> \stopformula
> \stoptext
>
> 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.
I'll add this:

\unprotect

\unexpanded\def\math_border_matrix#1#2#3% adapted plain
{\begingroup
%
\pushmacro\cr
%
\setbox\scratchbox\hbox\bgroup
\mr B%
\egroup
\scratchdimenone\wd\scratchbox
%
\scratchdimentwo.2\bodyfontsize
%
\mathsurround\zeropoint
%
\setbox\scratchboxone\vbox\bgroup
\def\cr{%
\crcr
\noalign\bgroup
\kern\scratchdimentwo
\global\let\cr\endline
\egroup
}%
\ialign{%
\startimath\alignmark\alignmark\stopimath
\hfil
\kern\dimexpr\scratchdimentwo+\scratchdimenone\relax
\aligntab
\thinspace
\hfil
\startimath\alignmark\alignmark\stopimath
\hfil
\aligntab
\aligntab
\quad
\hfil
\startimath\alignmark\alignmark\stopimath
\hfil
\crcr
\omit
\strut
\hfil
\crcr
\noalign{\kern-\baselineskip}%
#3\crcr
\omit
\strut
\cr
}%
\egroup
\setbox\scratchboxtwo\vbox\bgroup
\unvcopy\scratchboxone
\global\setbox\globalscratchbox\lastbox
\egroup
\setbox\scratchboxtwo\hbox\bgroup
\unhbox\globalscratchbox
\unskip
\global\setbox\globalscratchbox\lastbox
\egroup
\setbox\scratchboxtwo\hbox\bgroup
\startimath
\kern\dimexpr\wd\globalscratchbox-\scratchdimenone\relax
\left#1\relax
\kern-\wd\globalscratchbox
\global\setbox\globalscratchbox\vbox\bgroup
\box\globalscratchbox
\kern\scratchdimentwo
\egroup
\vcenter\bgroup
\kern-\ht\globalscratchbox
\unvbox\scratchboxone
\kern-\baselineskip
\egroup
\thinspace
\right#2\relax
\stopimath
\egroup
\null
\thickspace
\vbox\bgroup
\kern\ht\globalscratchbox
\box\scratchboxtwo
\egroup
%
\popmacro\cr
%
\endgroup}

\unexpanded\def\bordermatrix {\math_border_matrix()}
\unexpanded\def\bbordermatrix{\math_border_matrix[]}

\protect

\starttext

A plain border matrix:

\startformula
\bordermatrix{
a & b & c & d \cr
e & f & G & h \cr
i & j & k & l \cr}
\stopformula

\startformula
\bbordermatrix{
a & b & c & d \cr
e & f & G & h \cr
i & j & k & l \cr}
\stopformula

\stoptext


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