Once I seem to have worked on a system where, for some reason, latex code containing
$\array{a & b \\ c & d }$
seems to have worked. (Note that, in particular, the "alignment" options of the {rcrcr} kind, standard in the usual \begin{align} \end{align} construction, is missing here. Now I need to compile this on what is a more or less standard latex installation, and it does not compile as is. Of course, one option would be to edit everything into the standard \begin{align} \end{align}.
Question: can you recommend an alternative, so as to be able to compile such code with as little editing overhead as possible? Some package or option in the preamble?
\array
with\matrix
.