[PATCH] Implement print-circle, use it in the byte compiler.

[Stephen J. Turnbull]

Aidan Kehoe writes:

 >  > Haven't we had a feature of numbering self-referential objects, and
 >  > printing references to those objects in subobjects as numerical reference
 >  > since the turn of the millennium or so?
 > 
 > We have, yes, but that syntax throws an error on read.

That (throwing an error) sounds like feature to me!<wink/>

But I'm not going to veto.  Consenting adults ... don't ask, don't
tell ....