Microsoft.R.Core.AST.Operators.OperatorPrecedence.GetPrecedence C# (CSharp) Method

        public static int GetPrecedence(OperatorType operatorType) {
            // Lower number means lower priority. Lowest priority operators 
            // appear higher in the tree so they are evaluated last.
            switch (operatorType) {
                case OperatorType.Sentinel:
                    return 0;

                case OperatorType.Help:
                    return 10;

                case OperatorType.Equals:
                    return 20;

                case OperatorType.LeftAssign:
                    return 30;

                case OperatorType.RightAssign:
                    return 40;

                case OperatorType.DataTableAssign:
                    return 50;

                case OperatorType.Tilde:
                    return 60;

                case OperatorType.Or:
                case OperatorType.CondtitionalOr:
                    return 70;

                case OperatorType.And:
                case OperatorType.ConditionalAnd:
                    return 80;

                case OperatorType.Not:
                    return 90;

                case OperatorType.GreaterThan:
                case OperatorType.GreaterThanOrEquals:
                case OperatorType.LessThan:
                case OperatorType.LessThanOrEquals:
                case OperatorType.ConditionalEquals:
                case OperatorType.ConditionalNotEquals:
                    return 100;

                case OperatorType.Add:
                case OperatorType.Subtract:
                    return 110;

                case OperatorType.Multiply:
                case OperatorType.Divide:
                    return 120;

                case OperatorType.Modulo: // %%
                case OperatorType.IntegerDivide: // %/%
                case OperatorType.MatrixProduct: // %*%
                case OperatorType.OuterProduct: // %o%
                case OperatorType.KroneckerProduct: // %x%
                case OperatorType.MatchingOperator: // %in%
                case OperatorType.Special: // %abc%
                    return 130;

                case OperatorType.Sequence: // :
                    return 140;

                case OperatorType.UnaryMinus: // -
                case OperatorType.UnaryPlus: // +
                    return 150;

                case OperatorType.Exponent: // ^
                    return 160;

                // Although R table in https://stat.ethz.ch/R-manual/R-devel/library/base/html/Syntax.html 
                // lists @/$ as higher precedence than () and [] it is not correct. If $ was higher than ()
                // then func()$a could not be parsed correctly. C++ precedence table describes correct
                // precedence: (), [], . and -> have same precedence and left associativity.
                // See http://cs.stmarys.ca/~porter/csc/ref/cpp_operators.html

                case OperatorType.FunctionCall: // (...)
                case OperatorType.Index: // [], [[]]
                case OperatorType.ListIndex: // $ or @
                    return 170;

                case OperatorType.Namespace: // :: or :::
                    return 180;

                case OperatorType.Group: // ( ) around expression
                    return 190;
            }
            return 1000;
        }
    }

        private int GetCurrentOperatorPrecedence(ParseContext context, OperatorType operatorType, out bool isUnary)
        {
            isUnary = false;

            if (IsUnaryOperator(context.Tokens, operatorType, -1))
            {
                operatorType = OperatorType.Unary;
                isUnary      = true;
            }

            return(OperatorPrecedence.GetPrecedence(operatorType));
        }