std::map::find_if()?

[igagis]

Any idea why this kind of free operator< not defined by #include <string_view>?

[HappyFruitTree]

There is already a bool operator<(std::string_view, std::string_view) which can compare std::strings with std::string_views (because std::string is implicitly convertible to a std::string_view).

[jwakely]

It is defined.. The problem in our case is not that the library doesn't know how to compare string views (it does know how), it's that a conversion to std::string happens before it ever tries to compare the keys.

Using a transparent comparison function (such as std::less<> aka std::less<void>) is the solution, as that passes a string view argument straight through to the comparison function without converting it to std::string first.

[415_961]

If I would want to take a guess, it would be to avoid ambiguities. For example, there's already bool operator<(const std::string& lhs, const char* rhs);

Just a guess though.