“Transducers“ by Rich Hickey

People keep implementing map, filter and other fundamental algorithms in different contexts - eagerly over collections, over lazy sequences, in parallel, over enumerables/iterables, over observables, over channels/streams etc. In addition to duplication of effort, this yields bloated APIs, and, when implemented in the classic way, often involves the creation of expensive intermediate objects/values that can be difficult to optimize away. Most problematic is that this approach keeps us from composing core al