Catrobat.IDE.Core.Formulas.FormulaInterpreter.InterpretMinusToken C# (CSharp) Метод

        private IFormulaOperator InterpretMinusToken(IFormulaToken previousToken, FormulaNodeSubtract minusToken)
        {
            // change from subtract to negative sign token
            if (previousToken == null || previousToken is IFormulaOperator || previousToken is FormulaTokenParameterSeparator)
            {
                var negativeSignToken = FormulaTreeFactory.CreateNegativeSignNode(null);
                SetOrigin(negativeSignToken, minusToken);
                return negativeSignToken;
            }
            return minusToken;
        }