Eiffel Collection+json is a library to work with  Collection+JSON - Hypermedia Type,  http://www.amundsen.com/media-types/collection/

Project page: https://github.com/eiffelwebframework/collection_json

The current CJ implementation does not implement the [extensions][1] proposals,  
The google group is here [discussion group][2]

[1]: https://github.com/mamund/collection-json/tree/master/extensions "extensions"
[2]: https://groups.google.com/forum/?fromgroups#!forum/collectionjson "discussion group"