- From: Chris Dollin <chris.dollin@hp.com>
- Date: Mon, 23 Apr 2007 14:36:21 +0100
- To: semantic-web@w3.org
On Monday 23 April 2007 13:52, Eyal Oren wrote: > Now, for Sandro's proposal, in ActiveRDF properties return either singular > values (e.g. a foaf:Person) or an Array of values, depending on the number > of triples that carry that property for the given subject. Since we're > using a dynamic language such multi-typing is no problem: I disagree. It's no problem to /do/, it's a problem to /use/. Because: > # in one case we might return a single value > eyal.foaf::knows ==> renaud > > # but with a different data set an array > eyal.foaf::knows ==> [renaud, armin, stefan] ... you don't, in general, know how many items you've got, and so don't know whether to expect a singleton or a collection. (Yes, of course you can test, but then every point of access becomes a type-test, No Biscuit.) > # if you as programmer want an array in any case you can ask for it > eyal.foaf::all_knows ==> [renaud] Whereas this is easier to work with: you /always/ get an array, which you can iterate over. If you want exactly one value, you can check the size of the array. > I personally find this quite ok, without the need for plural properties? I'd much rather be able to have the method names express that I expect one thing vs a collection of things (and have expect-one explode if there's more than one property value. Or none, in languages (like Java) with second-class nils.) An alternative in friendly languages is to have an optional parameter expressing the plurality of the property in suitable fashion. -- "The path to the web becomes deeper and wider." - October Project Hewlett-Packard Limited registered office: Cain Road, Bracknell, registered no: 690597 England Berks RG12 1HN
Received on Monday, 23 April 2007 13:36:06 UTC