array-rank
array ⇒ rank
Returns the number of dimensions of array.
(array-rank (make-array '())) ⇒ 0
(array-rank (make-array 4)) ⇒ 1
(array-rank (make-array '(4))) ⇒ 1
(array-rank (make-array '(2 3))) ⇒ 2
Should signal an error of type type-error if its argument is not an array.