Effect System

Noun · Development

Definitions

  1. A type-level mechanism that tracks and controls the side effects a function may perform — such as I/O, exceptions, or state mutation. Languages like Koka, Unison, and Effekt have built-in effect systems.

    In plain English: A way for the programming language to track what actions (like reading files or printing) each function is allowed to do, catching mistakes before you run the code.

    Example: "The effect system guarantees this function only reads from the database and never writes — the compiler enforces it."

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