Tests whether or not the list passed to
the lexically current logical block
has been exhausted; see Section 22.2.1.1 (Dynamic Control of the Arrangement of Output).
If this list has been
reduced to nil, pprint-exit-if-list-exhausted terminates the execution
of the lexically current logical block except for the printing
of the suffix. Otherwise pprint-exit-if-list-exhausted returns nil.
Whether or not pprint-exit-if-list-exhausted is fbound in the
global environment is implementation-dependent;
however, the restrictions on redefinition and shadowing of
pprint-exit-if-list-exhausted are the same as for symbols in the COMMON-LISP package
which are fbound in the global environment.
The consequences of attempting to use pprint-exit-if-list-exhausted outside
of pprint-logical-block are undefined.
An error is signaled (at macro expansion time or at run time) if
pprint-exit-if-list-exhausted is used anywhere other than
lexically within a call on pprint-logical-block.
Also, the consequences of executing pprint-if-list-exhausted outside
of the dynamic extent of the pprint-logical-block which lexically
contains it are undefined.