Method checkExpression

src/Gui/Dialogs/DlgExpressionInput.cpp:351–416

}

void DlgExpressionInput::checkExpression(const QString& text)
{
    // now handle expression
    std::shared_ptr<Expression> expr(
        ExpressionParser::parse(path.getDocumentObject(), text.toUtf8().constData())
    );

    if (expr) {
        std::string error = path.getDocumentObject()->ExpressionEngine.validateExpression(path, expr);

        if (!error.empty()) {
            throw Base::RuntimeError(error.c_str());
        }

        std::unique_ptr<Expression> result(expr->eval());
        message = result->toString();

        expression = expr;
        okBtn->setEnabled(true);
        ui->msg->clear();

        // set default palette as we may have read text right now
        ui->msg->setPalette(okBtn->palette());

        auto* n = freecad_cast<NumberExpression*>(result.get());
        if (n) {
            Base::Quantity value = n->getQuantity();

            Base::Type typePath = getTypePath();
            if (typePath == App::PropertyString::getClassTypeId()
                || typePath == App::PropertyMap::getClassTypeId()) {
                // For string properties just take the result value without further checks
                message = App::quote(anyToString(result->getValueAsAny()));
            }
            else {
                if (!value.isValid()) {
                    THROWMT(Base::ValueError, QT_TRANSLATE_NOOP("Exceptions", "Not a Number"));
                }

                QString msg = QString::fromStdString(value.getUserString());
                if (impliedUnit != Base::Unit::One) {
                    if (!value.isDimensionless() && value.getUnit() != impliedUnit) {
                        THROWMT(
                            Base::UnitsMismatchError,
                            QT_TRANSLATE_NOOP("Exceptions", "Unit mismatch between result and required unit")
                        );
                    }

                    value.setUnit(impliedUnit);
                }
                else if (!value.isDimensionless()) {
                    msg += tr(" (Warning: unit discarded)");

                    QPalette p(ui->msg->palette());
                    p.setColor(QPalette::WindowText, Qt::red);
                    ui->msg->setPalette(p);
                }