/Note: I am deprecating this library in preference to Versioned-Objects which can do everything this can and more. I’ll keep this here for a while until I have something that really puts it to shame with Versioned-Objects. That is all./
Versioned-Arrays is a library allowing you to use arrays in a relatively cheap manner. See my blog post on it for more in depth treatment of the ideas behind it.
Basically it allows you to modify parts of a “versioned array,” which is a small wrapper around a Lisp array, and the resultant modified array, and the original array, only requires O(N+m) storage where N is the number of elements in the array and m is the number of edits that are made in between the two versions. It works very well for problems where you are interested in a set of arrays that are only a few edits apart. In fact in this case, the asymptotic behavior is constant time, just like with normal mutable arrays.
Arrays are created with
make-versioned-array, elements are accessed with
varef, and arrays are modified using
The library should be thread safe, but keep in mind, a given array has a single lock that is held even for reads. Thus contention can be a problem.
This is an ASDF package.
Not many dependencies, yay:
Additional dependencies for the test suite:
This is a pretty simple piece of code so I am publishing it under the 3 clause BSD license. It follows:
Copyright (c) 2011, Zach Kost-Smith All rights reserved.
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