A series is a data structure much like a sequence, with similar
kinds of operations. The difference is that in many situations,
operations on series may be composed functionally and yet
execute iteratively, without the need to construct intermediate
series values explicitly. In this manner, series provide both
the clarity of a functional programming style and the efficiency
of an iterative programming style. Series is the culmination of
many years of design and use of this approach, during which some
100,000 lines of application code have been written (by about
half a dozen people over the course of seven years) using the
series facility in nearly all iteration situations. This
includes one large system (KBEmacs) of over 40,000 lines of
code. In a nutshell: Think "Efficient MAPCAR". SERIES translates
functional-style expressions into efficient loops. RScheme is an
object-oriented, extended Scheme implementation with a compiler
that targets C or (RScheme's own) bytecodes. It has features
expected from a modern