Summary
This episode is the fourth chapter in Jason's special five-part Christmas class series on lambdas. Jason first explains the solution to Chapter 3's homework, demonstrating why lambdas defined inside fold expressions generate significantly more assembly code than lambdas defined outside them - each lambda inside a fold expression gets instantiated multiple times. He then introduces Chapter 4's focus on the evolution of lambdas across C++ standards, recommending four episodes covering C++17's constexpr lambda support and C++20's template syntax, usability changes, and parameter packs in captures. Unlike previous chapters, this one ends with an open-ended exercise asking viewers what lambda features they'd like to see in C++23.