On Sep 30, 5:04 am, Achim Passen <[EMAIL PROTECTED]> wrote:
> On Sep 30, 5:20 am, "Stephen C. Gilardi" <[EMAIL PROTECTED]> wrote:
>
> > After some more thought, I'm not sure whether this should be a concern
> > or not. Since jmap's purpose is to wrap Clojure maps for passing to
> > Java APIs, I'm not sure when it will be necessary to compare jmaps to
> > Clojure maps. In the abstract, it would be nice if they could be
> > compared for equality, but I'm not sure how important this is in
> > practice.
>
> I tend to agree. In most cases there should be no doubts whether a map
> at hand is wrapped or not. If otherwise, you could safely unwrap both
> via cmap (that's the reason why i wrote cmap to act "forgivingly" when
> not applied to jmaps) and then compare afterwards.
>
I've been thinking about this Map vs Collection issue for a while now
and am considering making the move to: Clojure maps implement Java
Map.
The jmap workaround highlights the awkwardness of not aligning with
Java here.
My current thoughts are:
- Java Maps not being Java Collections is truly sad, but not something
I can do anything about.
- For consumption from the Clojure side, I can hide that difference in
coll?, count, to-array etc.
- Code that looks for Collection currently matches Clojure maps but
wouldn't anymore. It never matched Java Maps. clojure code should move
to coll?, and for Java code I can provide RT.isCollection for
replacing instanceof calls.
- Using the ad hoc hierarchy support, I can unify Collection and Map
by deriving both from :Collection, thus allowing matches for all
collections in multimethods etc.
- The real reason to implement Java interfaces is to support use from
Java, where the limitations of Maps not being Collections is already a
fact of life, and Clojure maps not implementing Map a problem.
- If I'm going to do this, the sooner the better.
Any change in this area may involve some breakage, but I'm confident
there will be all necessary facilities to move existing code.
Feedback welcome,
Rich
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