Expected functionality required:

• A constexpr class that can be constructed from F-String or const char * as constexpr, and supports the below functionalities
  • constexpr case-sensitive comparison
  • constexpr case-sensitive equality
  • constexpr case-insensitive (US-EN, ASCII only) comparison
  • constexpr case-insensitive (US-EN, ASCII only) equality
  • constexpr case-sensitive uint32_t result hash function
  • constexpr conversion to lowercase (US-EN, ASCII only) version of string

Then, given constant arrays of const POD structures, where one member is a const char * null-terminated string...

• A constexpr function that, given that array and a hash of a target string, returns a first index to the matching string.

• A constexpr function that, given that array and a target string or F-String, returns an array index that contains a matching string.

  Psuedocode strawman

  // ignoring the C++11 requirement that a constexpr be a single return statement ... this is just psuedocode
  template<typename T, size_t INDEX>
  size_t IndexOfMatchingMemberImpl(T type, const char * stringToFind) {
      return ( constexpr_compliant_string_comparison( T[INDEX].Name, stringToFind ) == 0 ) ?
          INDEX :
          IndexOfMatchingMemberImpl<T, INDEX-1>(type, stringToFind);
  }
  template<typename T>
  size_t IndexOfMatchingMemberImpl<T,0>(T type, const char * stringToFind) {
      static_assert( constexpr_compliant_string_comparison( T[0].Name, stringToFind ) == 0, "Unable to find matching string" );
      return ( constexpr_compliant_string_comparison( T[0].Name, stringToFind ) == 0 ) ? 0 : -1;
  }
  template<typename T, size_t N>
  size_t IndexOfMatchingMember(T type[N], const char * stringToFind) {
      return IndexOfMatchingMemberImpl<T, N-1>(type, stringToFind);
  }

What the above could enable

• Products can store default patterns using friendly name, rather than opaque (and unstable) array index
• Configuration can store array index + hash of the string, to detect invalidation

Other considerations

Maybe there's already a library to do this?

See also:

• https://newbedev.com/how-to-declare-constexpr-c-string
• https://gist.github.com/dsanders11/8951887
• https://github.com/gelldur/gcpp/blob/master/src/gcpp/string/ConstexprString.hpp
• https://sourceforge.net/p/constexprstr/code/HEAD/tree/no-pp-constexpr_string.cpp