🚀 go-pugleaf

It's not possible to use the elisp debugger if there are any circular
structures on the stack.  (This makes debugging the VM mail reader
impossible.)

At first I thought all it would take was adding something like
  (condition-case c (print ...) (error (princ "--circular--")))
around the debugger's call to print, but this doesn't work because
prin1 is called from C code.

There should a print-depth variable as well as print-length.  Well really,
I'd rather have print-circle, even if it only did something like
   (foo bar (baz ## yow)) 
instead of
   (foo bar (baz (foo bar (baz (foo bar (baz ... yow)) yow)) yow))
which print-depth would do.

(For those of you who don't know, Common Lisp would do
   #1=(foo bar (baz #1# yow)) 
and read would correctly reproduce the structure.)

		-- Jamie