Async and generators

Spork maps asynchronous functions, awaiting, asynchronous iteration, and generators onto Python’s execution model. The forms on this page retain Spork’s expression and persistent-collection conventions where noted.

Async Functions#

Place the ^async compiler flag before the function name. await and async-for may only appear inside an async function. Like for, async-for eagerly returns a persistent vector after consuming the asynchronous iterable; it does not return a lazy async iterator.

(defn ^async fetch-data [url]
  (let [response (await (http.get url))]
    (await (response.json))))

; Eagerly transform an asynchronous iterable
(defn ^async load-items []
  (async-for [item (async-iterator)]
    (await (transform item))))

Generators#

Place ^generator before the function name when its body uses yield or yield-from.

(defn ^generator count-up [start]
  (loop [n start]
    (yield n)
    (recur (inc n))))

; Yield from (delegation)
(defn ^generator chain [& iterables]
  (doseq [it iterables]
    (yield-from it)))