On 1/13/2016 9:43 PM, Niall Douglas wrote:
#define STRING_VIEW(str) { str, sizeof(str)-1 } constexpr std::initializer_list<std::pair<const string_view, weekday>> string_to_weekday { { STRING_VIEW("sunday"), weekday::sunday }, { STRING_VIEW("monday"), weekday::monday }, { STRING_VIEW("tuesday"), weekday::tuesday }, { STRING_VIEW("wednesday"), weekday::wednesday }, { STRING_VIEW("thursday"), weekday::thursday }, { STRING_VIEW("friday"), weekday::friday }, { STRING_VIEW("saturday"), weekday::saturday } };
The macro `STRING_VIEW` seems unnecessary because the `string_view` constructor taking a single NULL-terminated string is also `constexpr`. Although, it could reduce the amount of computation done by the C++ interpreter in the compiler. Sadly, the current proposal for string_view does not provide a default Traits length function which is constexpr for const char *. Yes, I find that very daft as a default design choice for a string_view, but the macro at least makes it not too irritating.
Perhaps you can get rid of the macro this way: template <int Len> constexpr string_view str_view(const char (&s)[Len]) { return string_view(s, Len); }