v.t. (a stream)
to terminate usage of the stream as a source or sink of data,
permitting the implementation to reclaim its internal data structures,
and to free any external resources which might have been locked by the
stream when it was opened.
n. an object that is constrained (e.g., by its context in a program
or by the source from which it was obtained) to be immutable.
A literal object that has been processed by compile-file
is a constant object.