Purpose of Closed Lists
lA closed list is used
for its identity as an object, rather than purely for its value as a sequence.
lSeveral ÒclientsÓ can access the same closed list; modifications made by one will be seen by all.
lSeveral ÒclientsÓ can access the same closed list; modifications made by one will be seen by all.
lIn some cases, this is the
desired behavior.
lIn some cases, more
space-efficient due to in-place modification.