protected QueryBase VisitMatches(MatchesNode node, ElasticQueryMapperState state)
        {
            // TODO: Move these 3 lines to separate method for reuse?
            var fieldName = GetFormattedFieldName(node);
            var valueNode = node.GetValueNode <string>();
            var value     = ValueFormatter.FormatValueForIndexStorage(valueNode.Value, fieldName);

            // TODO: RegexOptions - does Elastic support this?
            return(new RegexpQuery
            {
                Field = fieldName,
                Value = value.ToStringOrEmpty(),
                Boost = node.Boost
            });
        }