System.Management.Pash.Implementation.ExecutionVisitor.VisitAssignmentStatement C# (CSharp) Method

        public override AstVisitAction VisitAssignmentStatement(AssignmentStatementAst assignmentStatementAst)
        {
            // first check if it's a assignable expression, fail otherwise. later on we also need support for
            // arrays of variables
            ExpressionAst expressionAst = assignmentStatementAst.Left;
            if (!SettableExpression.SupportedExpressions.Contains(expressionAst.GetType()))
            {
                var msg = String.Format("The expression type '{0}' is currently not supported for assignments",
                                        expressionAst.GetType().ToString());
                throw new NotImplementedException(msg);
            }
            var assignableExpression = SettableExpression.Create(expressionAst, this);
            var rightValue = EvaluateAst(assignmentStatementAst.Right);
            object newValue = rightValue;

            bool isSimpleAssignment = assignmentStatementAst.Operator == TokenKind.Equals;
            // safe the effort to get the value of the left side if it's replaced anyway
            dynamic currentValue = isSimpleAssignment ? null : assignableExpression.GetValue();

            // compute the new value
            if (isSimpleAssignment)
            {
                newValue = rightValue;
            }
            else if (assignmentStatementAst.Operator == TokenKind.PlusEquals)
            {
                newValue = ArithmeticOperations.Add(currentValue, rightValue);
            }
            else if (assignmentStatementAst.Operator == TokenKind.MinusEquals)
            {
                newValue = ArithmeticOperations.Subtract(currentValue, rightValue);
            }
            else if (assignmentStatementAst.Operator == TokenKind.MultiplyEquals)
            {
                newValue = ArithmeticOperations.Multiply(currentValue, rightValue);
            }
            else if (assignmentStatementAst.Operator == TokenKind.DivideEquals)
            {
                newValue = ArithmeticOperations.Divide(currentValue, rightValue);
            }
            else if (assignmentStatementAst.Operator == TokenKind.RemainderEquals)
            {
                newValue = ArithmeticOperations.Remainder(currentValue, rightValue);
            }
            else
            {
                throw new NotImplementedException("Unsupported operator: " + assignmentStatementAst.Operator.ToString());
            }

            if (this._writeSideEffectsToPipeline)
            {
                this._pipelineCommandRuntime.WriteObject(newValue);
            }

            // set the new value
            assignableExpression.SetValue(newValue);

            return AstVisitAction.SkipChildren;
        }