Chapter 3. Parallelization Using Reducers
Reducers are another way of looking at collections in Clojure. In this chapter, we will study this particular abstraction of collections, and how it is quite orthogonal to viewing collections as sequences. The motivation behind reducers is to increase the performance of computations over collections. This performance gain is achieved mainly through parallelization of such computations.
As we have seen in Chapter 1, Working with Sequences and Patterns, sequences and laziness are a great way to handle collections. The Clojure standard library provides several functions to handle and manipulate sequences. However, abstracting a collection as a sequence has an unfortunate consequence; any computation performed over all the elements of a sequence is inherently sequential. Also, all of the standard sequence functions create a new collection that is similar to the collection passed to these functions. Interestingly, performing a computation over...
