On Mon, 28 Jun 1993 15:58:55 -0400, Keith Moore
moore> Which we could require, if we're willing to state that
moore> there's never any circularities. Can an object have both
moore> "owner" & "requires"? Can these things nest or be mutually
moore> referential? How hard it will be to implement depends on
moore> this. A general-purpose implementation has to be fairly
moore> complex, but if we're willing to say that there's no cycles
moore> (possibly because you can't have both owner & requires, or
moore> possibly just because you aren't allowed to have cycles, so
moore> cycles can be treated as errors) then a linear implementation
moore> is more plausible, but the general mechanism is less
This is a problem with any scheme that permits recursive (singly or
multiply) links; one must be careful not to be trapped in a loop.
moore> I just realized that I might want to mail someone a set of
moore> application/html docs that have cyclic references among one
moore> another. Hmmm...
This is not so bad with hypertext documents; html links have sort of
implicit 'attachment' semantics, in that the links are not resolved
unless the user requests it.
Consider instead a compound image format, in which images A and B
referred to each other. It would be like facing two mirrors at each
other, but a lot more resource-intensive... :)
Perhaps MIME parsers should use recursion counting, like namei(), to
avoid infinite loops?