Re: Re: opaque type proposal

[Juan Loaiza <jrl@VX.LCS.MIT.EDU>]

      You still need the length check in order to make sure that the slot containing
      the ``tag'' object actually exists before trying to fetch its value.

        	Pavel

Think again about the trick I mentioned.  It is a dirty, underhanded,
shameful, slimy trick; but I think it works.  If a token for a type T
is only ever present in the N'th slot of an object of type T, then
looking at the N'th slot of any other object will never get you that
token.  It does not matter how many slots the other object has.  If it
has less than N slots you, will get a random slot out of another
object, but never the N'th slot (assuming no objects have zero
length).

For our young listeners out there, please don't try this trick at home.