Multimethod
A multimethod is a dispatch mechanism that selects an implementation by applying a dispatch function to multiple arguments, often using their runtime types or values.
Data-Oriented Programming: Reduce software complexity
A multimethod method is a function that provides an implementation for a particular dispatch value.
- How it is used
- Provides extensible polymorphism for generic maps, including single-, multiple-, and dynamic-dispatch designs.
- How deep it goes
- Explains dispatch responsibilities, validation, method wiring, defaults, and three dispatch forms through JavaScript examples.
- Examples
- Demonstrates animal greetings, multilingual animal greetings, name-length behavior, and author-name formatting.
- What you can do after
- Build it from scratch by defining a dispatch function, initializing a multimethod, wiring implementations, and calling it as a regular function.
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Clojure: The Essential Reference
A multimethod is a Clojure polymorphic function whose implementation is selected by applying a dispatch function to its arguments.
- How it is used
- Selects polymorphic behavior for values or data using arbitrary dispatch rules rather than type-only method selection.
- How deep it goes
- Explains declaration, method extension, custom hierarchies, removal, inspection, precedence, defaults, and dispatch failures.
- Examples
- Uses a data-driven calculator, runtime operator extension, temperature-based sound speed, collection dispatch, and recursive methods.
- What you can do after
- Build it from scratch, extend implementations, inspect dispatch state, resolve ambiguities, and diagnose unmatched or conflicting methods.
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Related concepts
- arrows/multimethodsimplemented by · arrows/multimethods is a JavaScript library that provides an implementation of multimethods.
- polymorphic dispatchhas part · Polymorphic dispatch is runtime selection of an operation implementation based on a call's arguments, function value, or context.
- methodhas part · A method is a callable operation associated with an object or type and invoked through that association.
- function overloadingimplements · Function overloading is defining multiple callable operations with the same name but different parameter signatures, with behavior selected according to the call.
- functionkind of · A function is a callable program unit that performs an operation, may accept inputs, and can produce a result or side effect.
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