Back to Basics: Type Erasure
summary
Explains how to implement type erasure step-by-step: start with representation and behavior split using void plus function pointers, build a reference form (no ownership), then a value form using heap allocation and lambdas for clone/delete* affordances, and finally show vtable/virtual-base and single-function-with-switch optimizations. Compares std::function, std::any, function_ref, unique_function and inplace_function, shows tradeoffs (heap cost, ABI, speed) and provides working code (Godbolt link) that demonstrates each approach.
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chapters (9)
- 0:00Introduction
- 1:00What is type erasure?
- 2:06Motivating type erasure in C++
- 7:00Representation and behavior
- 13:26Building type-erased types
- 23:10Affordances and special members
- 30:41Standard library examples
- 40:20Other applications
- 43:20Conclusion and Q&A
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