[texhax] matrices

[Philip TAYLOR [PC336/H-XP]]

Well, presumably the only hard bit is interpolating the {ccc}
(for $n$ c's, where $n$ is unknown in advance).  If that is the
case, you could always use the inbuilt facilities of \halign
to arbitrarily replicate a field in the preamble.  So, using
Plain TeX notation, you might write :

\let \\ = \cr
\def \matrix #1{$\left ( \vcenter \bgroup \halign \bgroup &\hfil ##\hfil\cr #1\crcr \egroup \egroup \right )$}
\matrix{a & b & c \\ d & e & f \\ g & h & i}
\matrix{a & b \\ c & d \\ f & g}
\end

Philip Taylor, RHBNC
--------
Joe Corneli wrote:
> 
> Hello,
> 
> I'm new to this list, and new to TeX hacking, though I've been using
> LaTeX to typeset math for about 4 or 5 years.  One thing that I haven't
> been able to get satisfied with is the way one has to enter matrices,
> viz.,
> 
> $\left ( \begin{array}{ccc}
> a & b & c \\ d & e & f \\ g & h & i
> \end{array} \right )$
> 
> I would like to compress all of this into a macro like
> the following:
> 
> $\matrix{a & b & c \\ d & e & f \\ g & h & i}$
> 
> The trick is detecting the number of columns dynamically, since I'd like
> the same macro to work in this setting too:
> 
> $\matrix{a & b \\ c & d \\ f & g}$
> 
> Is it possible to do something like this?  And can anyone suggest a way
> to get started on it?  Maybe there is already something built-in that I
> just don't know about, I'd love to hear about that too.
> 
> Joe
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