Transducers by Rich Hickey

This talk will describe transducers, a new library feature for Clojure (but of interest to other languages) that emphasizes composable, context-free, intermediate-free notions like ‘mapping’ and 'filtering’ and their concrete reuse across all of the contexts above.

A great elaboration of Rich Hickey’s original article on transducers. The idea is definitely applicable to other languages, especially those that feature first-class functions, and encourage reductions over collections. For example, tranducers.js brings the concept to JavaScript. 

Of particular note in this talk were the special considerations when dealing with state in a transducer, early termination (30:50), and completion.