Returns an object stored under the specified name, or
Proposes an unused name.
Compute and return a unique id.
Attempts to release the specified name.
the name under which an object was stored
true if released,
Atomically replaces an existing entry in the unique store with a new one.
the existing name
the expected old entry under the specified name
the new entry to store under the specified name
true if an existing entry was replaced,
Attempt to store the value
x with the
proposed name, or
null to assign any non-existing name
object to store
name under which
x was stored, or
null if proposed
name already existed (in which case, nothing was stored)
Atomically returns the values in this unique store.