CPL

[Daniel L. Weinreb <DLW@ALDERAAN.SCRC.Symbolics.COM>]

    Date: 20 Feb 87  2255 PST
    From: Dick Gabriel <RPG@SAIL.STANFORD.EDU>

    Moon thought this algorithm was the right thing for about a year (?).
    Why is what we now have the right thing? Why aren't we trying to think
    of a simple way for the user to have control of the CPL without making him
    write his own algorithm? We can provide some default, but I think that
    making someone write their own topological sort as the only alternative
    is a loser.

The answer to this problem in New Flavors is a per-flavor option that
lets you explicitly add partial-order constraints.  I think this would
be a good way to address the problems you raise.  It means that for
relatively small or simple application, in which the first two rules
fully specify the order, the right thing happens automatically.  For
larger or more complex applications, it let you explicitly control any
ambiguity that might be a problem, but does not force you to
completely enumerate every CPL (which would be a real pain in the
neck and make subsequent modifications awkward).