Multiple values for R4RS.

[Guillermo J. Rozas <jinx@hpesogg.hp.com>]

    Maybe there is enough consensus to allow agreement on the
    non-controversial aspects of multiple values for R4RS.  What do people
    think about adding only VALUES and APPLY-VALUES?

I don't think they are worth adding if ACCEPTS? is not included as
well.  ACCEPTS? allows a programmer to extend old operations into new
ones which match their continuation.  For example, QUOTIENT can be
cleanly upgraded to return two values when expected, but its old
single value when only one is expected.

The reason Mike and Morry added ACCEPTS? to the proposal is that I
did not consider it interesting without some way of providing the
functionality that I want.

Without ACCEPTS?, their use and functionality can be provided in user
code, although without the error checking or the efficiency of a
"native" implementation.