Per Bothner writes:

> The main problem with (2) is that it adds a new concept - an "index
> object" data-type.

I'd hate to specify three different kinds of indexed data types.

If we switched to index objects, could they be just vectors? They have
some hope of both being efficient and having tools already available.

As to efficiency, a general array as an index object would have a lot
of overhead, relative to its size. Otherwise it would be much better,
for using parts of arrays as indexes.
--
Jussi