Polymorphism is the facility that allows a language/program to make decisions during runtime on which method to invoke based on the types of the parameters sent to that method. The number of parameters used by the language/runtime determines the ‘type’ of polymorphism supported by a language. Single dispatch is a type of polymorphism where only … Read more
In short they come from to different conceptualizations that, in some languages where double dispatch is not natively supported, lead to the visitor pattern as a way to concatenate two (or more) single dispatch in order to have a multi-dispatch surrogate. In long The idea of multiple dispatch is – essentially – allow a call … Read more
The visitor pattern is a way of doing double-dispatch in an object-oriented way. It’s useful for when you want to choose which method to use for a given argument based on its type at runtime rather than compile time. Double dispatch is a special case of multiple dispatch. When you call a virtual method on … Read more