Deveel.Data.Sql.Query.QueryTablePlanner.EvaluateSingles C# (CSharp) Method

        private void EvaluateSingles(List<SqlBinaryExpression> list, List<ExpressionPlan> plans)
        {
            // The list of simple expression plans (lhs = single)
            var simplePlanList = new List<SingleColumnPlan>();
            // The list of complex function expression plans (lhs = expression)
            var complexPlanList = new List<SingleColumnPlan>();

            foreach (var expression in list) {
                // The single var
                ObjectName singleVar;
                SqlExpressionType op = expression.ExpressionType;
                SqlExpression left = expression.Left, right = expression.Right;

                if (expression.Right is SqlQuantifiedExpression) {
                    singleVar = expression.Left.AsReferenceName();

                    if (singleVar != null) {
                        plans.Add(new SimpleSelectPlan(this, singleVar, op, expression.Right));
                    } else {
                        singleVar = expression.Left.DiscoverReferences().First();
                        plans.Add(new ComplexSinglePlan(this, singleVar, expression));
                    }
                } else {
                    singleVar = expression.Left.DiscoverReferences().FirstOrDefault();
                    if (singleVar == null) {
                        // Reverse the expressions and the operator
                        var tempExp = left;
                        left = right;
                        right = tempExp;
                        op = op.Reverse();
                        singleVar = left.DiscoverReferences().First();
                    }

                    var tableSource = FindPlan(singleVar);

                    // Simple LHS?
                    var v = left.AsReferenceName();
                    if (v != null) {
                        AddSingleColumnPlan(simplePlanList, tableSource, v, singleVar, new []{left, right}, op);
                    } else {
                        // No, complex lhs
                        AddSingleColumnPlan(complexPlanList, tableSource, null, singleVar, new []{left, right}, op);
                    }
                }
            }

            plans.AddRange(simplePlanList.Select(plan => new SimpleSinglePlan(this, plan.UniqueName, plan.Expression)).Cast<ExpressionPlan>());
            plans.AddRange(complexPlanList.Select(plan => new ComplexSinglePlan(this, plan.UniqueName, plan.Expression)).Cast<ExpressionPlan>());
        }