Expression VisitSelect(Expression source, Expression selectExpression)
        {
            var lambda = selectExpression.GetLambda();

            if (lambda.Parameters.Count != 1)
                throw new NotSupportedException("Select method with T parameter is supported, additional parameters like index are not");

            var selectBody = lambda.Body;

            if (selectBody is MemberExpression)
                RebindPropertiesAndElasticFields(selectBody);

            if (selectBody is NewExpression)
                RebindSelectBody(selectBody, ((NewExpression)selectBody).Arguments, lambda.Parameters);

            if (selectBody is MethodCallExpression)
                RebindSelectBody(selectBody, ((MethodCallExpression)selectBody).Arguments, lambda.Parameters);

            finalItemType = selectBody.Type;

            return Visit(source);
        }
        Expression VisitWhere(Expression source, Expression lambdaPredicate)
        {
            var lambda = lambdaPredicate.GetLambda();

            var criteriaExpression = lambda.Body as CriteriaExpression ?? BooleanMemberAccessBecomesEquals(lambda.Body) as CriteriaExpression;

            if (criteriaExpression == null)
                throw new NotSupportedException(string.Format("Where expression '{0}' could not be translated", lambda.Body));

            searchRequest.Filter = AndCriteria.Combine(searchRequest.Filter, criteriaExpression.Criteria);

            return Visit(source);
        }
        Expression VisitOrderBy(Expression source, Expression orderByExpression, bool ascending)
        {
            var lambda = orderByExpression.GetLambda();
            var final = Visit(lambda.Body) as MemberExpression;
            if (final != null)
            {
                var fieldName = Mapping.GetFieldName(SourceType, final);
                var ignoreUnmapped = final.Type.IsNullable(); // Consider a config switch?
                searchRequest.SortOptions.Insert(0, new SortOption(fieldName, ascending, ignoreUnmapped));
            }

            return Visit(source);
        }
        Expression VisitQuery(Expression source, Expression predicate)
        {
            var lambda = predicate.GetLambda();
            var wasWithin = within;
            within = CriteriaWithin.Query;
            var body = BooleanMemberAccessBecomesEquals(lambda.Body);

            var criteriaExpression = body as CriteriaExpression;
            if (criteriaExpression == null)
                throw new NotSupportedException(string.Format("Query expression '{0}' could not be translated", body));

            searchRequest.Query = AndCriteria.Combine(searchRequest.Query, criteriaExpression.Criteria);
            within = wasWithin;

            return Visit(source);
        }