Method tryEvaluateParametric

src/backend/gsl/ExpressionParser.cpp:770–812

}

bool ExpressionParser::tryEvaluateParametric(const QString& xexpr,
											 const QString& yexpr,
											 const QString& min,
											 const QString& max,
											 int count,
											 QVector<double>* xVector,
											 QVector<double>* yVector) {
	gsl_set_error_handler_off();

	const Range<double> range{min, max};
	const double step = range.stepSize(count);

	Parser parser(true);
	ParserLastErrorMessage lock(parser, m_lastErrorMessage);

	const auto numberLocale = QLocale();
	for (int i = 0; i < count; i++) {
		parser.assign_symbol("t", range.start() + step * i);
		parser.assign_symbol("i", i + 1);

		double x = parser.parse(qPrintable(xexpr), qPrintable(numberLocale.name()));
		if (parser.parseErrors() > 0) // try default locale if failing
			x = parser.parse(qPrintable(xexpr), "en_US");
		if (parser.parseErrors() > 0)
			return false;

		double y = parser.parse(qPrintable(yexpr), qPrintable(numberLocale.name()));
		if (parser.parseErrors() > 0) // try default locale if failing
			y = parser.parse(qPrintable(yexpr), "en_US");
		if (parser.parseErrors() > 0)
			return false;

		if (std::isnan(x))
			WARN(Q_FUNC_INFO << ", WARNING: X expression " << STDSTRING(xexpr) << " evaluated @ " << range.start() + step * i << " is NAN")
		if (std::isnan(y))
			WARN(Q_FUNC_INFO << ", WARNING: Y expression " << STDSTRING(yexpr) << " evaluated @ " << range.start() + step * i << " is NAN")

		(*xVector)[i] = x;
		(*yVector)[i] = y;
	}

	return true;
}

QString ExpressionParser::errorMessage() const {
	return m_lastErrorMessage;