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by mahmud 5587 days ago
Well, what do you know, Clojure records and hash-tables are equal (strongly.)

I will announce this great news to a few of my closest friends :-)
2 comments
jkkramer 5587 days ago
Almost. Record types are checked as part of full equality. So record Foo{:x 1} is not equal to Bar{:x 1} or to {:x 1}.
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w01fe 5586 days ago
Almost. Record types are checked as part of Clojure's "=", but not as part of Java's ".equals". See [1] and linked material. This means that Foo{:x 1} and Bar{:x 1} will collide in sets and as map keys (of Clojure or Java varieties). This seems a bit icky to me, but seems to be intentional.

[1] http://dev.clojure.org/jira/browse/CLJ-736

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lukev 5587 days ago
Records also provide better performance than hash tables for their defined keys.

You can think of them as a Java class that has certain fields (it's named fields) and also implements the Map interface for additional expandability. Records provide "accessor" methods for their named fields that provide bare-metal JVM performance.

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