This page is part of the web mail archives of SRFI 44 from before July 7th, 2015. The new archives for SRFI 44 contain all messages, not just those from before July 7th, 2015.
At Tue, 28 Oct 2003 21:37:26 -0600, scgmille@xxxxxxxxxxxxxxxxxx wrote: > > [1 <text/plain; us-ascii (quoted-printable)>] > On Tue, Oct 28, 2003 at 07:42:20PM -0800, Tom Lord wrote: > > > > > From: scgmille@xxxxxxxxxxxxxxxxxx > > > > > There is simply no way to have genericly programmable > > > collections without some generic dispatch mechanism. Nearly all > > > Scheme implementations currently have it. > > > > So what if they do? Are those mechanisms standardized in a SRFI? > > They don't need to be, just as the mechanisms for implementing > continuations or threads don't need to be standardized to support > SRFI-18. It would be nice if they were, but we can have a portable > implementation without them. The methods for implementing continuations don't need to be standardized because they are already standardized and specified in R5RS. Threads have a standardization in SRFI-18 - if you were to write a future SRFI that used multi-threading it would need to either depend on SRFI-18 or a new threading SRFI, but it would be poor precedent to depend on library X that implements co-routines for Scheme without first some agreement on library X. Otherwise the discussion for that SRFI in effect has to validate not only the specific points of the SRFI but of the chosen library as well. Most Schemes have a dispatch mechanism, but they come in many flavors. I suspect the TinyCLOS, StKLOS, SOS and Meroon families are close enough to work together, but YASOS and the MzScheme object system are quite different. And even among the similar ones, there's no guarantee that the "similar" systems won't encounter strange incompatibilities with future sub-classing and extension of the hierarchy. Saying "most Schemes can do generic dispatch" is not a solid foundation. Saying "this SRFI uses TinyCLOS" requires standardization of TinyCLOS first. And noone would take a cond-dispatch approach seriously since it is slow and not forwards compatible. You don't, however, need a full-blown, mother-of-all object systems for this SRFI. You just need single-dispatch for an single-inheritance hierarchy, which could be done in a very simple SRFI. -- Alex