UNICODE char literal

gistfile1.txt

  case '"':
    return lexStringLiteral(Token::StringModifiers(0));
  case '\'':
    return lexChar();
  case '`':
    return lexEscapedIdentifier();
  }
}

void Lexer::lexChar() {
  const char *TokStart = CurPtr;
  uint32_t c = 0;
  if (*CurPtr == '\\') {
    switch (*++CurPtr) {
      case 'r': c = '\r'; break;
      case 'n': c = '\n'; break;
      case '\'': c = '\''; ++CurPtr; break;
      case '\\': c = '\\'; break;
      default:
        diagnose(CurPtr, diag::lex_character_invalid_escape);
    }
  }
  else {
    c = swift::validateUTF8CharacterAndAdvance(CurPtr, BufferEnd);
    if (*CurPtr != '\'' || c == ~0U) {
      diagnose(TokStart, diag::lex_character_not_codepoint);
      c = 0;
    }
  }

  // nobody is suggesting for a minute this is how this should be done
  // but it does have all the right semantics.
  static char *charLiteralBuffer, *nextAvailable;
  static const ptrdiff_t buffsize = 1000;
  if (!charLiteralBuffer || nextAvailable - charLiteralBuffer > buffsize - 20) {
    auto mem = llvm::MemoryBuffer::getNewMemBuffer(buffsize);
    charLiteralBuffer = nextAvailable = (char *)mem->getBufferStart();
    ((SourceManager *)&SourceMgr)->addNewSourceBuffer(std::move(mem));
  }

  char *newLiteral = nextAvailable;
  nextAvailable += sprintf(nextAvailable, "%u", c);
  NextToken.setToken(tok::integer_literal, StringRef(newLiteral));

  while (*CurPtr++ != '\'');
}