Function FormatEnum

library/cpp/yt/string/enum-inl.h:87–129

template <class T>
void FormatEnum(TStringBuilderBase* builder, T value, bool lowerCase)
{
    auto formatLiteral = [&] (auto* builder, TStringBuf literal) {
        if (lowerCase) {
            CamelCaseToUnderscoreCase(builder, literal);
        } else {
            builder->AppendString(literal);
        }
    };

    if constexpr (TEnumTraits<T>::IsBitEnum) {
        if (None(value)) {
            // Avoid empty string if possible.
            if (auto optionalLiteral = TEnumTraits<T>::FindLiteralByValue(value)) {
                formatLiteral(builder, *optionalLiteral);
            }
            return;
        }

        TDelimitedStringBuilderWrapper delimitedBuilder(builder, " | ");

        T printedValue{};
        for (auto currentValue : TEnumTraits<T>::GetDomainValues()) {
            // Check if currentValue is viable and non-redunant.
            if ((value & currentValue) == currentValue && (printedValue | currentValue) != printedValue) {
                formatLiteral(&delimitedBuilder, *TEnumTraits<T>::FindLiteralByValue(currentValue));
                printedValue |= currentValue;
            }
        }

        // Handle the remainder.
        if (printedValue != value) {
            NYT::NDetail::FormatUnknownEnumValue(&delimitedBuilder, TEnumTraits<T>::GetTypeName(), value & ~printedValue);
        }
    } else {
        if (auto optionalLiteral = TEnumTraits<T>::FindLiteralByValue(value)) {
            formatLiteral(builder, *optionalLiteral);
            return;
        }

        NYT::NDetail::FormatUnknownEnumValue(builder, TEnumTraits<T>::GetTypeName(), value);
    }
}

template <class T>
std::string FormatEnum(T value)