Editing Multiple dispatch (section)

====Efficiency====

Efficient implementation of single-dispatch, including in programming languages that are separately compiled to object code and linked with a low-level (not-language-aware) linker, including dynamically at program load/start time or even under the direction of the application code, are well known.  The "[[vtable]]" method developed in C++ and other early OO languages (where each class has an array of function pointers corresponding to that class's virtual functions) is nearly as fast as a static method call, requiring O(1) overhead and only one additional memory lookup even in the un-optimized case.  However, the vtable method uses the function name and not the argument type as its lookup key, and does not scale to the multiple dispatch case.  (It also depends on the object-oriented paradigm of methods being features of classes, not standalone entities independent of any particular datatype).

Efficient implementation of multiple-dispatch remains an ongoing research problem.