Function IsValidPlainScalar

lib/yamlcpp/src/emitterutils.cpp:155–199

}

bool IsValidPlainScalar(const std::string& str, FlowType::value flowType,
                        bool allowOnlyAscii) {
  // check against null
  if (IsNullString(str)) {
    return false;
  }

  // check the start
  const RegEx& start = (flowType == FlowType::Flow ? Exp::PlainScalarInFlow()
                                                   : Exp::PlainScalar());
  if (!start.Matches(str)) {
    return false;
  }

  // and check the end for plain whitespace (which can't be faithfully kept in a
  // plain scalar)
  if (!str.empty() && *str.rbegin() == ' ') {
    return false;
  }

  // then check until something is disallowed
  static const RegEx& disallowed_flow =
      Exp::EndScalarInFlow() | (Exp::BlankOrBreak() + Exp::Comment()) |
      Exp::NotPrintable() | Exp::Utf8_ByteOrderMark() | Exp::Break() |
      Exp::Tab() | Exp::Ampersand();
  static const RegEx& disallowed_block =
      Exp::EndScalar() | (Exp::BlankOrBreak() + Exp::Comment()) |
      Exp::NotPrintable() | Exp::Utf8_ByteOrderMark() | Exp::Break() |
      Exp::Tab() | Exp::Ampersand();
  const RegEx& disallowed =
      flowType == FlowType::Flow ? disallowed_flow : disallowed_block;

  StringCharSource buffer(str.c_str(), str.size());
  while (buffer) {
    if (disallowed.Matches(buffer)) {
      return false;
    }
    if (allowOnlyAscii && (0x80 <= static_cast<unsigned char>(buffer[0]))) {
      return false;
    }
    ++buffer;
  }

  return true;
}

bool IsValidSingleQuotedScalar(const std::string& str, bool escapeNonAscii) {
  // TODO: check for non-printable characters?