Ruby's Enumerator#feed is a little-known method that enables bidirectional communication between an Enumerator and its caller. While most developers use Enumerators as one-way value streams, feed allows the caller to inject a value that becomes the return value of yield inside the Enumerator, effectively creating coroutine-like suspension and resumption with state. Practical examples show how to build interactive workflows without instance variables or external state. Though rarely needed in typical Rails apps, it's useful for DSLs, parsers, custom interpreters, and experimental concurrency systems.
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A Simple EnumeratorWhen Enumerators Need InputA Two-Way ConversationBuilding a Tiny Interactive WorkflowHow Does It Work?Why Does Ruby Have This?Is It Useful?Final ThoughtsShare this:Related2.4K Impressions