Since Elasticsearch already uses jackson for parsing, it would probably be kind of easy to plugin hocon using the jackson plugin for this. I learned about hocon last week when somebody from Solr was pointing out they were supporting that in Solr 6. This would make a lot of sense in Elasticsearch as well.
I recently played with this on my own pet project jsonj and there's not much to it to integrate it. One line of code and It just kind of works. Json is fully supported so there are no backwards compatibility issues.
Has this been done already and/or would it be easy to support in a plugin? I'd be interested in this for several reasons:
- more forgiving syntax and a bit more compact syntax
- easy to add comments so people can document their complex queries with inline comments
- Hocon's value substitution would make a lot of sense for more complex ES queries and templating those.