reshare array

Hi,

I am a Lisp newbie, sorry if this question has a simple answer, I
tried googling and found nothing.

Consider an n-dimensional simple array, eg

(setf a (make-array '(2 3 4) :element-type 'double-float))

If I understand correctly, a simple boxed array is just a vector of
numbers (in this case, 12 zeros), and information on the dimension (2
3 4).  Is it possible to "reshape" the array by changing only the
latter?  Eg 

(reshape a '(4 3))

would give a 4x3 array with the same elements, etc.  A special case
would be reshaping to a simple vector, or reshaping a simple vector to
an array.

Is there such a function already in CMUCL, or is it possible to write
one without too much hassle?  Even a desctructive reshape! would be
enough for my purposes.

Thanks,

Tamas


PS. matlisp already has such a reshape, but only for matrices.