On Tuesday, April 21, 2015 at 5:28:40 AM UTC-7, Julien Eluard wrote: > I am also curious about the advantages of using something like Clara versus > DataScript listen feature. Especially there has been discussions [1] of > improving listen so that it can accept a query details argument. > Alan I can see you commented on this ticket how do you think it compares to > Clara? > > Cheers, > Julien > > [1] https://github.com/tonsky/datascript/pull/12
The two are very close in concept but I think, under some conditions, Clara has an advantage in being based on the Rete algorithm. My guess is that the Rete algorithm might be more efficient but am unsure where the cost/benefit cross over is re: # rules, amount of data, etc.. It heavily depends on how much commonality/overlap and sharing happens in the graph which is dependent on your rules and their structure. Caveat emptor. Rete doesn't have to recompute the results of the query over and over again as data arrive like I suspect Datascript would have to. With Datascript, after each query is run there is no memory of what the previous results were. Rete maintains the state of all of your rules/queries across all of your data that you insert/remove in/out it. Re: Datascript and listen! At a conference a couple years ago I asked Rich a similar question re: Datomic, I couldn't hear his response very well but I think he said that Datomic doesn't support persistent queries and probably won't. I would think that datalog could handle it but I don't know how you'd do it. I think that pull request says the same thing basically if I'm reading it right. I know this kind of thing is very powerfule - I embedded Jess into IE 4 as a Windows Scripting Engine way back in the day. Just like javascript, Jess code could be embedded in your page using <script language="jess">(defrule xyz ...) </script> and you had full access to the DOM and events, with all the event wiring/registration happening automagically, etc. It made for a really elegant programming model. It worked great but internally it was a tangled mess of C++ COM objects, jscript, and java. IE 5 broke everything so I gave up on it. As previously mentioned, I'll post a more complete example of Clara tomorrow after I recover from my trip. Take care. -- Note that posts from new members are moderated - please be patient with your first post. --- You received this message because you are subscribed to the Google Groups "ClojureScript" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojurescript+unsubscr...@googlegroups.com. To post to this group, send email to clojurescript@googlegroups.com. Visit this group at http://groups.google.com/group/clojurescript.
