This is a C++20 implementation of the type erasure + visitor design patterns.
See test_package directory.
Relative measurements of calling area() and perimeter() on a vector of shapes (margin : ± 0.02). The number 1, 2, 3, 4, and 5 represents the number of Shape types (Circle, Square, Rectangle, Right Triangle, Rhombus) in the vector. Benchmark : g++ – 11.4 ; Catch 2 – 100 iterations ; 10'000'000 shapes
| 1 | 2 | 3 | 4 | 5 | |
|---|---|---|---|---|---|
| Type erasure | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Type erasure + visitor (fct pointer) | 1.13 | 1.04 | 1.05 | 1.04 | 1.03 |
| Type erasure + visitor (std::function) | 1.12 | 1.06 | 1.05 | 1.05 | 1.04 |
| Type erasure – vtable | 1.07 | 0.86 | 0.84 | 0.84 | 0.83 |
| Type erasure + visitor (fct pointer) – vtable | 1.16 | 0.92 | 0.92 | 0.88 | 0.87 |
| Type erasure + visitor (std::function) – vtable | 1.16 | 0.96 | 0.94 | 0.90 | 0.90 |
| std::variant & std::visit | 0.84 | 0.91 | 0.88 | 0.89 | 0.89 |
