EuroClojure Day 2

Okay so this post maybe happening a little later than Friday but in my defence there were some excellent conversations to go with the after-conference drinks.

Day 2 featured two talks by Rich Hickey, I had already seen some of the Datomic stuff from QCon and the web so I found the stuff on the new reducers library more engaging. I have never thought of map having an implicit ordering promise.

Meikel Brandmeyer gave a historical review of lazy seq which was really helpful for understanding laziness (something I have a bit of a problem with). One of the real highlights though was Chris Ford’s talk about canon music. It started with a good gag about sheet music being a DSL for using the finite state machine otherwise known as a musician. However the really amazing thing was Chris’s abstraction of the score and subsequent transformations of the abstract score to end up with variations on the base canon he had chosen. Really amazing. Chris’s talk really shouldn’t have been a lightning talk, it is about the only quibble I had with the programming.

Sam Newman also had an excellent closing line in his lightning talk on Riemann, which was if people want Clojure to be adopted widely then the secret is to create great things with Clojure.


EuroClojure 2012 Day 1

So there were definitely two big themes in the talks on the first day of the conference.

The first has been about how to use event-based systems to create flexible aggregate data models. All speakers seem to have settled on a reduce or foldLeft approach for creating the aggregate but there have been two models put forward already CQRS and a kind of Aggregate query bus but really it seems that responsibility for accepting event data and allow querying and access to aggregated views seem to be responsibilities in the same system.

The other thing has been creating query systems using logical predicates. The were no less than three generic query systems put forward: core.logic for low-level flexible implementations that identify either data or results and two general query libraries: one from Datomic and the other from Cascalog.