Hi Stef,<br><br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Thanks for the explanation frank<br>
btw (did you dd it in the class comment because it would be gorgeous).<br>
I learned something today so I&#39;m happy.<br>
Now what is the typical use case for such persistent structure?<br>
<br>
Stef</blockquote><div><br></div><div>Immutable data structures are used extensively in functional languages in which data structures are <b>im</b>mutable by default. One benefit of the approach is when�multi-threading you don&#39;t need to synchronise changes to such structures or objects containing them. For example all Clojure&#39;s data-structures are immutable by default [1].�There&#39;s been a lot of interesting work on providing performance guarantees so that creating copies avoids scaling with linear time [2], while still having sensible access and iteration performance.�</div>
<div><br></div><div>[1]�<a href="http://clojure.org/data_structures#Data%20Structures-Collections">http://clojure.org/data_structures#Data%20Structures-Collections</a></div><div>[2] <a href="http://clojure.org/functional_programming#Functional%20Programming--Immutable%20Data%20Structures">http://clojure.org/functional_programming#Functional%20Programming--Immutable%20Data%20Structures</a></div>
<div><br></div><div>Apologies if I&#39;m stating the obvious</div><div><br></div><div>Nick</div></div>