Similar to the Common lisp *print-length*. If set, this
limits how many elements of a list to print (at any level).
replacement-alist
Ordinary (non-fast) alist. Binds subterms either to
strings (which are interpreted as the eviscerated
replacement text for the subterms) or else to
replacement terms (which are not to be recursively
eviscerated).
hiding-cars
Should be a fast alist. Binds symbols to T. Any subterm
whose car is bound in hiding-cars will be
eviscerated with <hidden>.
