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Generic interfaces Daphne Preston-Kendal (23 Jul 2021 11:34 UTC)
Re: Generic interfaces Lassi Kortela (23 Jul 2021 11:48 UTC)
Against hierarchy Lassi Kortela (23 Jul 2021 11:56 UTC)
Re: Against hierarchy Marc Nieper-Wißkirchen (23 Jul 2021 12:04 UTC)
Re: Against hierarchy Lassi Kortela (23 Jul 2021 12:08 UTC)
Re: Against hierarchy Marc Nieper-Wißkirchen (23 Jul 2021 12:26 UTC)
R6RS exception hierarchy Lassi Kortela (23 Jul 2021 12:39 UTC)
Re: R6RS exception hierarchy Marc Nieper-Wißkirchen (23 Jul 2021 13:09 UTC)
Re: R6RS exception hierarchy Lassi Kortela (23 Jul 2021 16:05 UTC)
Re: R6RS exception hierarchy Marc Nieper-Wißkirchen (23 Jul 2021 16:24 UTC)
Re: R6RS exception hierarchy Arthur A. Gleckler (23 Jul 2021 17:19 UTC)
Re: R6RS exception hierarchy Marc Nieper-Wißkirchen (23 Jul 2021 17:49 UTC)
Re: R6RS exception hierarchy Arthur A. Gleckler (23 Jul 2021 19:28 UTC)
Re: R6RS exception hierarchy John Cowan (26 Jul 2021 21:32 UTC)
Re: R6RS exception hierarchy Marc Nieper-Wißkirchen (27 Jul 2021 05:46 UTC)
Re: Generic interfaces Daphne Preston-Kendal (23 Jul 2021 17:47 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (23 Jul 2021 18:17 UTC)
Re: Generic interfaces Adam Nelson (23 Jul 2021 18:55 UTC)
Re: Generic interfaces Per Bothner (24 Jul 2021 19:31 UTC)
Re: Generic interfaces John Cowan (24 Jul 2021 04:27 UTC)
Re: Generic interfaces John Cowan (24 Jul 2021 04:26 UTC)
Re: Generic interfaces Daphne Preston-Kendal (25 Jul 2021 09:08 UTC)
Re: Generic interfaces Amirouche (25 Jul 2021 14:36 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (23 Jul 2021 12:18 UTC)
Re: Generic interfaces Daphne Preston-Kendal (23 Jul 2021 17:49 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (23 Jul 2021 17:51 UTC)
Re: Generic interfaces Daphne Preston-Kendal (23 Jul 2021 18:12 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (23 Jul 2021 18:39 UTC)
Re: Generic interfaces John Cowan (24 Jul 2021 03:56 UTC)
Re: Generic interfaces John Cowan (24 Jul 2021 02:22 UTC)
Re: Generic interfaces Jeremy Steward (24 Jul 2021 03:38 UTC)
Re: Generic interfaces Amirouche (25 Jul 2021 06:19 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (25 Jul 2021 08:39 UTC)
Re: Generic interfaces Daphne Preston-Kendal (25 Jul 2021 09:28 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (25 Jul 2021 10:04 UTC)
Re: Generic interfaces Daphne Preston-Kendal (25 Jul 2021 10:47 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (25 Jul 2021 12:16 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (29 Jul 2021 08:18 UTC)
Re: Generic interfaces John Cowan (26 Jul 2021 00:04 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (26 Jul 2021 06:25 UTC)
Re: Generic interfaces John Cowan (26 Jul 2021 12:26 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (26 Jul 2021 13:00 UTC)
Re: Generic interfaces Ray Dillinger (26 Jul 2021 19:28 UTC)
Re: Generic interfaces John Cowan (26 Jul 2021 19:53 UTC)
Re: Generic interfaces Arthur A. Gleckler (26 Jul 2021 22:15 UTC)
Re: Generic interfaces John Cowan (25 Jul 2021 23:37 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (26 Jul 2021 06:10 UTC)
Re: Generic interfaces John Cowan (26 Jul 2021 11:43 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (26 Jul 2021 12:09 UTC)
Re: Generic interfaces John Cowan (26 Jul 2021 13:14 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (26 Jul 2021 13:37 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (16 Nov 2021 18:52 UTC)
Re: Generic interfaces John Cowan (25 Jul 2021 23:00 UTC)
Re: Generic interfaces Marc Nieper-Wißkirchen (26 Jul 2021 05:44 UTC)

Re: Generic interfaces Daphne Preston-Kendal 25 Jul 2021 09:08 UTC

On 24 Jul 2021, at 06:26, John Cowan <xxxxxx@ccil.org> wrote:

> Go with A or with B?  Why not both, however you please to use them?
> <snip>
> Well, if someone turns fast generics into a SRFI implementation (writing the SRFI text will be easy) along the lines I've sketched, we can get them on the next ballot or two -- but there is no reason for them to be mutually exclusive.

If the point of dictionaries is to establish a standard way to talk to key-value mapping objects regardless of their implementation, which will be used in future SRFIs and Scheme libraries, then surely it *is* a question of whether our approach to that particular question looks more like SRFI 225 (in its new incarnation with user-specified dictionary type descriptors) or more like CLOS/fast-generics/whatever?

>> However, generic functions in Scheme have many of the same performance issues as the SRFI 225 (first draft) registration system. Since the only portable typing mechanism we have are predicates, not type descriptors, the only easy way for many implementations to do typing dispatch is calling each predicate in turn.
>
> Fast-generics allows you to specify predicate subsumptions, which is isomorphic to subtype relationships.  If the predicate P1 subsumes P2, then the type of objects satisfying P2 is a subtype of the type of objects satisfying P1.  So when doing fast-generics on top of a JVM/CLR style type tree, we extend the subsumption relation to know about its subtypes, and then we can cleverly make use of its built-in dispatching.

Yes, but predicates can be arbitrary Scheme procedures in a way that type descriptors corresponding to Java classes/etc can't be, making this trickier. (I guess we make it ‘an error’ to use a predicate which isn’t one of a disjoint type as defined in the spec or created by define-record-type or whatever procedural records layer we adopt?)

Daphne