#pjson

And here we go with another issue of Clojure Weekly! Clojure Weekly is a collection of bookmarks, normally 4/5, pointing at articles, docs, screencasts, podcasts and anything else that attracts my attention in the clojure-sphere for the last 7 (or so) days. I add a small comment so you can decide if you want to look at the whole thing or not. That’s it, enjoy!

Clojure eXchange 2015 | 3rd - 4th Dec 2015 | London In case you've missed it, this is the week of Clojure Exchange! Mailonline is proudly sponsoring this year, so we'll have our booth downstair for questions, chatting, whatever. If you happen to be around for the conference please step by to say hi. The program is pretty interesting. I'm personally looking forward to Nicola Mometto, Martin Trojer, Chris Ford talks and many others.

gerritjvv/pjson A new Clojure Json parsing library out there that claims to be the fastest. The documentation is pretty clear: it is giving away some validation processing for speed. So there are trade-offs. But if speed is all you need, this library can be for you. It looks like it boils down to use sun.misc.Unsafe for strings allocation (so I suppose they are allocated in native memory but I didn't check). Interesting nonetheless.

polymatheia - Parsing TeX with Recursive Transducers This is a very interesting idea. This post describes an approach to syntax parsing using transducers comparing it to similar techniques like clojure.walk to obtain the same effect. The grammar in question is TeX but the same approach applies to other markups, like Json, Html and so on. Compared to walking the AST the transducers approach avoid the sequence allocation problem. It's also very composable. Say you have a system where different services feed on the same Json source. Each service needs some common "cleanup" operations on the raw Json before applying specific transformations. If the transformations are modelled with transducers snippets, they can be easily reused across services for the common part.

Videos - Datomic Uh wait, what? There was a Datomic conference! Here are the videos, plus screencasts and some videos on Datomic from other conference. I'd really love to use Datomic in my next project, but I failed to sell it to the business here. There is just not enough understanding about why Datomic is a superior product in many respects. The odd license model also play against it (that is, knowing in advance how many JVM will connect to it) and business people don't know how to handle it. Too bad.

How to call Clojure Macros from Java? - Stack Overflow Interesting question. Unfortunately the answer is you can't "directly" because the macro is an expansion in place that happens at compile time. In theory you would have to invoke the compiler first to have your macro compiled down into an object and then invoke it. The smart solution presented here just goes inside the macro and invokes what's inside. You might not be as lucky.