Issue: PRINT-CIRCLE-STRUCTURE (Version 1)

[David A. Moon <Moon@STONY-BROOK.SCRC.Symbolics.COM>]

    Date: 5 Oct 88 20:47 PDT
    From: masinter.pa@Xerox.COM

    Circularities need only be detected for
    objects that would normally be printed by the default structure
    print-function.

I cannot accept any proposal with this kludgey restriction in it.  If
circularities are going to be detected at all, they should be done
right.  It's not difficult to call the user-defined print-function once
with a special stream argument that detects what the function prints
(i.e. what calls to WRITE and equivalent functions and FORMAT directives
it makes using that stream), and use that for circularity detection.
That's how the Symbolics Genera implementation works.