Peter Dimov
[...]
As it turns out, there has been such a proposal, N3599:
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3599.html
later referenced by two competing proposals for compile-time string literals, N4121 and N4236:
https://isocpp.org/files/papers/n4121.pdf http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4236.html
N3599 has been however rejected, as the committee apparently feels that representing compile-time strings as char packs is inefficient and impractical, and prefers constexpr char arrays.
`constexpr` char arrays and character packs are not equivalent. The problem is that constexpr-ness is stripped away by argument passing. For illustration, consider the following example: template <typename CompileTimeString> void f(CompileTimeString s) { static_assert(s == "abc", ""); } constexpr std::string_literal<n> n4121 = "abc"; constexpr auto n4236 = "abc"_s; f(n4121); // error: s is not constexpr within the body of f f(n4236); // ok: the value of s is contained in its type The only way to achieve this with N4121 is to unpack the `std::string_literal` into a template holding a character pack, passing this to `f` and then doing the comparison with a character pack. But then this is equivalent to N4236. Regards, Louis