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• A Clojure performance nemesis: reflection. This is a really good overview of reflection in Clojure, how to spot it, and how to fix it.
• I’ve launched a free and open source service Deps Versions for adding a dependency status badge to your open source Clojure projects. I wrote a bit more about it on the Deps blog.
• State in re-frame
• Cats and Dogs with Cortex Redux
• A ClojureScript visual cheatsheet
• David Nolen was on the CaSE podcast.

People are worried about Types. ?

• There is a lengthy thread on the Clojure mailing list about spec’s unintuitive (IMO) behaviour for validating keys. The specific part that I’m worried about is that no error is thrown at runtime if you specify a keyword in s/keys that hasn’t been defined. It seems like the kind of thing that could leak into production, or mask bugs further down the line.
• Semantic integrity checks is a new feature of a configuration language Dhall, which lets you verify that the semantics of your API haven’t changed. I could imagine something similar being applied to APIs that have been specced in Clojure, to automatically detect breaking changes.

Foundations.

• Cliff Click talking about modern hardware performance and cache lines
• Mark Reinhold and Brian Goetz on Moving Java forward faster, and Java’s new rapid six monthly release cycle. Highly recommended if you want to see the future direction Java is heading.
• Here’s the release schedule for JDK 10
• Intel has released persistent collections for Java. However these are for efficient usage of non-volatile persistent memory, not persistent data structures.

Tools.

• Datomic now has a forum
• Clojureverse has a poll on how you compile your ClojureScript
• Thomas Heller on the background of shadow-cljs

Recent Developments.

• Clojure 1.9.0 RC1 is out

Learning.

• Mike Fikes on avoiding unnecessary conversions of JS objects to CLJS, and the resulting performance boost you can gain.
• Clojure debugging

Misc.

• Long time member of the Clojure[Script] community Chas Emerick has a Patreon up. If you’ve benefited from his work, either now or in the past, then consider sponsoring it.