Can this class work with wchar_t / std::wstring?

[htonus]

Bug Report

• What is the issue you have?
  Failed to parse wchar_t string
• Please describe the steps to reproduce the issue. Can you provide a small but working code example?
  json::parse(wstring) failed
• What is the expected behavior?
  the string was parsed
• And what is the actual behavior instead?
  error
• Which compiler and operating system are you using? Is it a [supported compiler]
  VS 2017 Community edition
• Did you use a released version of the library or the version from the develop branch?
  Took from developer branch
• If you experience a compilation error: can you compile and run the unit tests?

Feature Request

• Describe the feature in as much detail as possible.

• Include sample usage where appropriate.

[nlohmann]

Related: #722 #216

[nlohmann]

wstring is currently not supported.

[htonus]

That's pity. Thank you.

[nlohmann]

Well, I think it this could be fixed by writing an input adapter for std::wstring, std::u16string, and std::u32string. I'll see what I can do.

[nlohmann]

So my naive approach would be to implement an input adapter for std::wstring, std::u16string, and std::u32string and take care of the translation between UTF-32 and UTF-16 to UTF-8, respectively. This adapter would read a character from the string and internally offer several UTF-8 bytes to the consumer of the input adapter. This would allow to reuse the lexer/parser chain for JSON files.

I shall open a feature branch, but would be happy for any comment whether I overlooked some fundamental flaw in this idea.