Hi Alec:
Whether or not you end up using bidirectional refs, I'd enjoy spending a few minutes tomorrow brainstorming about how they might be used if you're interested.
John
John Anderson wrote:
I don't think you should rule out using bidirectional refs because everyone is busy -- although there may be other reasons to rule them out. We use bidirectional refs in so many places that not being familiar with them is a pretty serious handicap. There are lots of examples in the code that uses them and I suspect none of us is really too busy to answer a question about them now and then.
John
Alec Flett wrote:
John Anderson wrote:
As it turns out there are lots of ways to do this. The "kind query" scheme you're proposing is just one way we've discussed doing it. Another interesting possibility we've discussed is using bidirectional references on ref collections, e.g. assigning an attribute hooks the a corresponding reference on the other end of a system collection that can be used to find the registered things. Another possibility we've discusses is executing code at parcel load time -- which seems not quite as nice as the two previous data driven schemes. Finally, none of these deal with the possibility of allowing the user to participate in choosing between registered alternatives, e.g. choosing between alternative viewers for a particular datatype.I agree that a data-driven mechanism is the way to go - at least in the general case. Personally I think that the bi-directional reference with a container system seems like our best bet - my "Kind" mechanism is not ideal. (and I've done code-executing-at-startup and it ends up being pretty ugly)
I think in the case of the sidebar, however, it would be nice to register a new item collection as well as an optional viewer (today we only have two, table and calendar). However, all this is beyond the scope of 0.5.That's not a problem I'm trying to solve for 0.5 anyway... so that's good.
This is clearly an area that needs to be fleshed out post 0.5, with input from UI, design and by considering our other registration needs, so I think it's premature to add it as described without further discussion.I need it for ZaoBao as a proof-of-concept of extensions actually working in Chandler without being hard coded in. Given the realities of 0.5 (such as me not knowing enough about references in the repository or the parcel loader, and other folks being busy) I'd like to move forward with the "Kind" mechanism and discuss something better (i.e. the bidirectional reference mechanism) as well as the issue of user-intervention, for 0.6.
Alec
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