C++ Type Erasure | Unified Interfaces Without Inheritance
이 글의 핵심
How type erasure works and when standard-library facilities already use it.
What is type erasure?
Type erasure hides concrete types behind a small, stable interface—often via a concept table + erased storage (std::function, std::any, custom Drawable wrappers).
graph TD
A[Stable API] --> B[Concept interface]
B --> C[Model for type A]
B --> D[Model for type B]
std::function
Erases callable types with a given signature:
std::function<int(int,int)> f = [](int a, int b) { return a + b; };std::any
Stores any copyable value; type must be recovered with any_cast and correct type.
Manual pattern
Drawable holding unique_ptr<DrawableConcept> + templated DrawableModel<T>—see the Korean article for a full sketch.
Tradeoffs
| Virtuals | Type erasure | |
|---|---|---|
| Inheritance | Required | Not required |
| Indirection | vtable | often heap + function pointers |
| Flexibility | Limited to hierarchy | Many unrelated types |
Related posts
- std::any
- Polymorphism
Keywords
C++, type erasure, std::function, std::any, design patterns