Implementing `variant` visitation using lambdas

The interface they expose, however, is often more cumbersome to use than it needs to be: defining exhaustive visitors requires the user to create a class with several operator() overloads, or to create a chain of if constexpr(...) calls. Both solutions are not very elegant.

After a brief overview of std::variant and its usefulness, this talk will focus on the implementation of a "lambda-based in-place visitation" approach, where the user can visit a variant by simply providing a set of lambdas on the spot. This will require implementing a way of overloading arbitrary function objects.

Recursive variant types will then be covered and the "lambda-based" visitation techniques will be applied to them. This will require implementing the "Y combinator" higher-order function to achieve zero-runtime-overhead lambda recursion.

This talk is intended for developers familiar with C++11 and C++14 core language features (lambdas, variadic templates, auto, etc...). Prior knowledge of std::variant or sum types is not required.

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