Multiple values for R4RS.

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

    This is an extreme position.  The proposed functionality is
    useful even in the absence of ACCEPTS?  

It's much less extreme than imposing a particular fascist semantics on
those who don't find it interesting or useful.  Usefulness is an
aesthetic measure, and I find CPS better if I'm going to be fascist.

    I remain unconvinced.  As a user, I have found multiple values
    (without ACCEPTS?) quite useful.  So, I don't think ACCEPTS? provides
    super-essential functionality.  As an implementor, I would prefer not
    to be committed to keeping around arity information for every
    procedure.

You don't have to keep it around for every procedure.  Just those
procedurs that might be given to ACCEPTS? as arguments.  This may seem
silly, but I'm not kidding.  This effectively means that only closures
(and not all of them) need to have this information.  The MIT Scheme
compiler keeps arity information only for procedures that it
determines may be invoked from places that "don't know about them."
This turns out to be but a fraction of the total in typical code.