The array_dims(M) function returns the equivalent of [rtable_dims(M)], but works on arrays and lists as well.

When M is a scalar the result will always be [ 1..1 ].

$\mathrm{with}\left(\mathrm{MTM}\right)\:$

$\mathrm{array\_dims}\left(\left[\left[1\,2\right]\,\left[3\,4\right]\right]\right)$

$\left[1..2\,1..2\right]$