Contents of -matrices

-matrices

??=[matrix] The fundamental command of this feature is the command ||...|| that reads a matrix of entries in the generic TEX row&column format, , where rows are separated with |
| and contain columns separated with |&|. Thus a matrix with "maxrow" rows and "maxcol" columns where each entry contains "row"|,|"col" is entered as

\| $\displaystyle \xymatrix$ \|
\| 1, 1	\|	\| 1, 2	\| ^...
\|
\| 2, 1	\|	\| 2, 2	\|
\|
$\displaystyle \vdots$	$\displaystyle \ddots$
"maxrow"\|, 1	\|	"maxrow"\|, 2	\|

(TEXnically the |&| character represents any `alignment tab', , character with category code 4).

A <matrix> can appear either in an -picture (as <decor>) or ``stand-alone''.

The points where || is different from ordinary matrix constructions (like plain TEX's ||...|| and L^ATEX's |array| environment) are

arbitrary -pic <decor>ations may be specified in each entry and will be interpreted in a state where c is the current entry,
the entire matrix is an object itself with reference point as the top left entry, and
a progress message ``|<xymatrix| "rows"|x|"cols" "size"|>|'' is printed for each matrix with "rows"×"cols" entries and -pic complexity "size" (the number of primitive operations performed).
Entries starting with a |*| are special (described in §??[entries]), so use |*| to get a $\star$ .

For example,
$\begin{code} \begin{displaymath}\xy \xymatrix{A&B\\ C&D} \drop\frm{-} \drop\cir<8pt>{} \endxy\end{displaymath}\end{code}$
will typeset In fact entries of one matrix may refer to entries of another by using the <pos> save mechanism:
$\begin{code} \begin{displaymath}\xy \xymatrix { A\POS=''A'' & B\POS=''B'' \\ ... ...r{.} & D'\POS;''D''**\dir{.} } \POS*\frm{--} \endxy\end{displaymath}\end{code}$
was typeset (using the `frame' extension) by

: Matrices cannot be nested.

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