Problem

Consuming iterated/pagenated APIs is a frequent need for Clojure devs but writing code that consumes them efficiently and handles various flow patterns is nuanced.

Approach

Add a generator function to clojure.core for iterated API calls, that can represent iteration e.g. HTTP endpoints that return continuation tokens.

Background

Examples of tasks within this problem category include:

1. using aws-api everyday - lots of APIs return continuation tokens and you have to stitch calls together

2. walking up a superclass hierarchy: Long -> Number -> Object

3. collecting exception cause chains

Common approaches use some combination of iterate and take-while and while expedient, this approach couples the "beget" part of the iteration protocol with the "has-more?" part of the protocol. A ticket that attempted to address iterated protocols was CLJ-1906. Rich created an example iteration function that provided an a la carte iterated API consumer.

Screened By: Fogus

Patch: clj-2555-iteration.patch