CS代考计算机代写 === ALL USERS PLEASE NOTE ========================

=== ALL USERS PLEASE NOTE ========================

CAR and CDR now return extra values.

The function CAR now returns two values. Since it has to go to the
trouble to figure out if the object is carcdr-able anyway, we figured
you might as well get both halves at once. For example, the following
code shows how to destructure a cons (SOME-CONS) into its two slots
(THE-CAR and THE-CDR):

(MULTIPLE-VALUE-BIND (THE-CAR THE-CDR) (CAR SOME-CONS) …)

For symmetry with CAR, CDR returns a second value which is the CAR of
the object. In a related change, the functions MAKE-ARRAY and CONS
have been fixed so they don’t allocate any storage except on the
stack. This should hopefully help people who don’t like using the
garbage collector because it cold boots the machine so often.