Function parseRational

libsolidity/experimental/analysis/TypeInference.cpp:907–948

{

std::optional<rational> parseRational(std::string const& _value)
{
	rational value;
	try
	{
		auto radixPoint = find(_value.begin(), _value.end(), '.');

		if (radixPoint != _value.end())
		{
			if (
				!all_of(radixPoint + 1, _value.end(), util::isDigit) ||
				!all_of(_value.begin(), radixPoint, util::isDigit)
			)
				return std::nullopt;

			// Only decimal notation allowed here, leading zeros would switch to octal.
			auto fractionalBegin = find_if_not(
				radixPoint + 1,
				_value.end(),
				[](char const& a) { return a == '0'; }
			);

			rational numerator;
			rational denominator(1);

			denominator = bigint(std::string(fractionalBegin, _value.end()));
			denominator /= boost::multiprecision::pow(
				bigint(10),
				static_cast<unsigned>(distance(radixPoint + 1, _value.end()))
			);
			numerator = bigint(std::string(_value.begin(), radixPoint));
			value = numerator + denominator;
		}
		else
			value = bigint(_value);
		return value;
	}
	catch (...)
	{
		return std::nullopt;
	}
}

/// Checks whether _mantissa * (10 ** _expBase10) fits into 4096 bits.
bool fitsPrecisionBase10(bigint const& _mantissa, uint32_t _expBase10)