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Re: A possible solution?

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.

> Bear wrote:
>> SRFI-44 does not need to depend on any OO framework or library to get
>> dynamic dispatch based on the collection type .... Therefore consider
>> as a possibility, a vector a few dozen elements long.  Let the first
>> element, at index zero, contain a symbol .... And it'll work.
>> Immediately.  And it'll be totally clear to everybody how to write
>> collections that this interface can use.

Anton van Straaten wrote:
> This could make a nice reference implementation.  It's not completely
> clear to me whether you're also suggesting that this should be
> something that the spec requires of implementations, though.  I don't
> see the need for it in implementations that already provide a generic
> dispatch mechanism - it would only add overhead.

I think the spec needs some way for implementors to portably "hook into"
the dispatch system. Otherwise, users will have a hard time extending
the set of collections, which defeats the purpose of having the generic
interfaces. They'll need to rely on the internals of the local SRFI-44
implementation. The situation is worse for independent library authors,
because they'll have one more portability issue to deal with.

On the one hand, I really don't think it's a good idea to tie the
interface down to a specific delegation mechanism. On the other hand,
you'll have these portability problems if you don't supply *some* method
of extending the set of delegations.
Bradd W. Szonye