September 2015
Intermediate to advanced
198 pages
4h 52m
English
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Transients
Earlier in this chapter, we discussed the virtues of immutability and the pitfalls of mutability. However, even though mutability is fundamentally unsafe, it also has very good single-threaded performance. Now, what if there was a way to restrict the mutable operation in a local context in order to provide safety guarantees? That would be equivalent to combining the performance advantage and local safety guarantees. That is exactly the abstraction called transients, which is provided by Clojure.
Firstly, let's verify that it is safe (up to Clojure 1.6 only):
user=> (let [t (transient [:a])] @(future (conj! t :b))) IllegalAccessError Transient used by non-owner thread clojure.lang.PersistentVector$TransientVector.ensureEditable (PersistentVector.java:463) ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.