Learn Datalog Today – An interactive Datomic query tutorial

http://www.learndatalogtoday.org/

by jonase • 13 years ago

84 7 13 years ago

learndatalogtoday.org

brudgers2• 13 years ago

The standard Racket environment also includes an implementation of Datalog.

http://docs.racket-lang.org/datalog/

peatmoss• 13 years ago

Why, when I was surveying lisps to learn, was Racket an afterthought for me? I ultimately started learning Clojure, which is great, but has the benefit / curse of the JVM. As I play around in Racket (and look over at Typed Racket), I realize how nice a language it is.

The one thing I really miss from Clojure, however, is the destructuring bind. I'd love it if someone smarter than me could opine on how hard it would be to extend Racket with destructuring bind...

brudgers2• 13 years ago

Racket is actually both a language and a distribution of a set of tools for building languages - e.g. the Racket distribution includes not only Racket and Datalog, but Algol-60 just to show off how flexible the tool set is.

One of the advantages and curses of the Racket community is that it comes out of academia rather than business like Clojure. The benefit is that it has good documentation and someone somewhere is writing or has written a thesis about just about anything based on Racket. The downside is that Racket is many things to many people and there is no canonical source like Rich Hickey or Linus.

I'm not smarter - Hell, I don't even know what a destructuring bind is. But [it is the internet after all] maybe you want

  (match...)

http://docs.racket-lang.org/reference/match.html?q=match&q=r...

Anyway, There's always IRC.

mahmud• 13 years ago

Why is that a problem? No one ever learns just one Lisp. Must collect them all :-)

iso-8859-1• 13 years ago

Here's an online Datalog IDE and evaluator, running wholly client-side. Made with Emscripten.

http://ysangkok.github.io/mitre-datalog.js/wrapper.html

Adrock• 13 years ago

The order of the data patterns does not matter (aside from performance considerations)

I just started using Datomic for a little project. The performance implications of the order of the data patterns matters a lot. It's not a minor performance consideration when swapping two patterns results in having a full cartesian product of two moderately large fact sets stored in memory. You fill up your heap and wait a long time to just get an OOM error. Very quickly, you realize that you need to think about how the query engine will deal with your request.

It seemed strange to me to dismiss this when it's something that I had to face on day 1.

Learn Datalog Today – An interactive Datomic query tutorial

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