…and thus code is no longer sending _a_ message to _an_ object but using argument types to pick which function/procedure to call. The “cast” function is no longer coupled with any single class, so in effect this problem with OOP has been fixed by not using OOP concepts to solve the problem.
Or, as I sometimes think of it, it can be an OOP design if multiple dispatch is actually a set of messages supported by an implicit, singleton, and usually hidden, “multiple dispatch“ object that handles the dispatch logic. You don’t have to write “dispatcher.cast(a, b, c)” but that is because the language provides the syntactic sugar (and often, an efficient implementation).
