On Sun, 11 Sep 2011, Philipp A. wrote:

> 2011/2/23 Mathieu Boespflug <0xbadcode@gmail.com>
>
>> Hi all,
>>
>> just as a followup and for the mailing list archives, the solution is
>> to use both Aditya's suggestion to turn on \donknuthmode, as well
>> replacing the & signs with their interpretations, namely
>> \pgfmatrixnextcell. Thank you Aditya for the suggestion.
>>
>> Regards,
>>
>> Mathieu
>
>
> umm, i can’t seem to get it to work. i use the mkiv minimals…
>
> no combination of \donknuthmode, \nonknuthmode, \pgfmatrixnextcell and
> “replace ampersand=foo”, that i tried, seems to work.
>
> can anyone give me a minimal example of a working tikz matrix in a context
> document? (preferrably something that prevents me from littering everything
> with “\pgfmatrixnextcell”)

One way around this is to re-read part of tikz module code under the right 
catcode regime (ideally this should be done by t-tikz). I still cannot get 
& to work, but using \& is a reasonable shortcut.

Here is a working example:

\usemodule[t-tikz]
\usetikzlibrary{matrix}

\unprotect
\ReadFile{pgfmodulematrix.code.tex}
\protect

\starttext
\tikzstyle{description}=[fill=white,inner sep=2pt]
\starttikzpicture
     \matrix(m)[matrix of math nodes,
       row sep=3em, column sep=3em,
       ampersand replacement=\&,%% AM: Added this.
       text height=1.5ex, text depth=0.25ex]
            {x \& y\\
             z \& u\\};
     \path[->]
       (m-1-1) edge node[description] {$*$} (m-1-2)
               edge node[description] {$*$} (m-2-1)
       (m-1-2) edge[dashed] node[description] {$*$} (m-2-2)
       (m-2-1) edge[dashed] node[description] {$*$} (m-2-2);
\stoptikzpicture
\stoptext

Aditya