Editing Double dispatch (section)

{{Short description|Feature in programming languages}}
{{Polymorphism}}
In [[software engineering]], '''double dispatch''' is a special form of [[multiple dispatch]], and a mechanism that dispatches a function call to different concrete functions depending on the runtime types of two objects involved in the call. In most [[object-oriented]] systems, the concrete function that is called from a function call in the code depends on the dynamic type of a single object and therefore they are known as [[single dispatch]] calls, or simply [[virtual function]] calls.

[[Dan Ingalls]] first described how to use double dispatching in [[Smalltalk]], calling it [[multiple polymorphism]].<ref>A Simple Technique for Handling Multiple Polymorphism. In Proceedings of [[OOPSLA]] '86, Object–Oriented Programming Systems, Languages and Applications, pages 347–349, November 1986. Printed as SIGPLAN Notices, 21(11). {{ISBN|0-89791-204-7}}</ref>