this bears on my new package, though, for two reasons:

(1) it's only about sequences; maps don't fit into its framework.

(2) He is proposing here a change that would have to be made

to every Common Lisp implementation. As may have been

apparent from other email I've sent, I am, sadly, pessimistic

that we can really get all of the implementors to make changes

in harmony. It's not that they are bad or incompetent or

anything like that. It's just that they're busy people with

other priorities. In some cases, the priorities include

"putting food on the table" (in the metaphorical sense),

i.e. it would be easier if someone could pay them to

do this, but I don't see how that would happen.

Anyway, thanks for pointing me at this very interesting

On Tue, Jun 14, 2011 at 10:13 AM, Alessio Stalla <alessiostalla@gmail.com> wrote:

On Tue, Jun 14, 2011 at 3:38 PM, Daniel Weinreb <dlw@google.com> wrote:
> Could you tell me where to find that? Thanks. -- Dan

The paper - titled "User-extensible sequences in Common Lisp" by C.
Rhodes - can be found for example here:
<http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.65.1604&rep=rep1&type=pdf>

I don't remember how well the paper describes SBCL's implementation; I
think it's worth taking a look at it to see how it combines CLOS (for
genericity) with regular functions special-cased on CL built-in types.
ABCL's impl is almost a clone of SBCL's, with only minor adaptations.

I agree that classes in CLOS are overrated. CLOS is mainly about
generic functions and it's a pity, imho, that GFs can only be
specialized on classes. With minor changes CLOS could be more general.

Cheers,
Alessio