structures in fasl files

[Charlie Farnum <farnum@sequoia.berkeley.edu>]

I have been bitten several times by the fact that circular/shared
structures are saved naively in fasl files; e.g., compiling the
following one line file will cause an infinite loop:

(defconstant x '#1=(#1#))

Today I found an internal variable compiler::*fasl-circle* that, when
set to t, makes the above work as it should.

1) Can I get some sort of reassurance that this variable, or something
similar, will stay around in future releases (at least on Suns and
DECstations)?

2) Why isn't this documented, and why isn't t the default value?  It
would appear to be much more in line with CLTL's assurance that
compiled code and interpreted code should work the same...

  /charlie