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InstanceDispatch.jl is a single-macro package to mix enumerations (or anything that defines a method forBase.instances) and dispatch-on-value in Julia.

Simply put it allows using dispatching in a type-stable fashion by writing code such as:

using InstanceDispatch@enum GreetEnum Hello Goodbyefunctiongreet(::Val{Hello}, who)return"Hello"* whoendfunctiongreet(::Val{Goodbye}, who)return"Goodbye"* whoend@instancedispatchgreet(::GreetEnum, who)

This last line is equivalent to defining the following method:

functiongreet(e::GreetEnum, who)if e== Helloreturngreet(Val(Hello), who)elseif e== Goodbyereturngreet(Val(Goodbye), who)elseendend

This avoidsthe performance pit that you would encounter in simply writing:

functiongreet(e::GreetEnum, who)returngreet(Val(e), who)end

import Pkg; Pkg.add("InstanceDispatch")

• ValSplit.jl essentially performs the same task forSymbol-based value type dispatch.