Editing Visitor pattern (section)

==== Visit ====
Thus, the implementation of the <code>visit</code> method is chosen based on both the dynamic type of the element and the dynamic type of the visitor. This effectively implements [[double dispatch]]. For languages whose object systems support multiple dispatch, not only single dispatch, such as [[Common Lisp]] or [[C Sharp (programming language)|C#]] via the [[Dynamic Language Runtime]] (DLR), implementation of the visitor pattern is greatly simplified (a.k.a. Dynamic Visitor) by allowing use of simple function overloading to cover all the cases being visited. A dynamic visitor, provided it operates on public data only, conforms to the [[open/closed principle]] (since it does not modify extant structures) and to the [[single responsibility principle]] (since it implements the Visitor pattern in a separate component).

In this way, one algorithm can be written to traverse a graph of elements, and many different kinds of operations can be performed during that traversal by supplying different kinds of visitors to interact with the elements based on the dynamic types of both the elements and the visitors.