Custom Overload Sets and Inline SFINAE for Truly Generic Interfaces
summary
Shows how C++17 features (void_t, template deduction guides, invoke, constexpr if, decltype(auto) on lambdas) let code pick the first compilable option, pick the best overload, or test validity of expressions without heavy boilerplate. Builds a validator/is_valid utility that makes inline SFINAE work via lambda return-type deduction, an overload_sequence that chooses the first callable that compiles (demonstrated with element_count selecting size, distance, or 1), and a type_selector that picks the first type making expressions valid. Works on Clang; deduction-guide trick currently breaks on some GCC cases; overload_set can’t handle final classes or unions yet.
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chapters (8)
- 0:00Introduction and motivation
- 7:43SFINAE limitations and challenges
- 13:53Inline SFINAE with lambdas
- 23:53Overload sequences for ranked calls
- 31:51Overload sets for best match
- 42:15Understanding callable types
- 48:53Type selection with expressions
- 51:56Summary and conclusions
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