API for new ddo and ddf data stores

[kaneplusplus]

I'm thinking about adding a Redis connection for storing ddf and ddo data. However, I'm having a little bit of trouble understanding. Is there a list of functions that need to be implemented to do this? Will I only need to implement a new connection? Is implementing a constructor, addData, removeData, print, loadAttrs and saveAttrs sufficient?

[hafen]

That would be very cool! Yes, how to add a new back end is not documented - something I've been meaning to do. I can give a few pointers here but now that I know of a potential use case I can put more immediate effort into documenting the api.

The main things that need to be implemented are

1. A data connection to initialize either an existing data store on the back end or a pointer to where data will be put on the back end
2. ddo / ddf - specific methods for this back end (mostly how to get/set attributes and how to extract values by key)
3. A map/reduce implementation that bridges R to the back end

Once you have those three, everything else will work.

For (1), you would create a file conn_redis.R and look at the other conn_* files for inspiration. For (2), you would create a file ddo_ddf_redis.R. For (3), you would create a file mapreduce_redis.R. These all require more depth of explanation - I'll work on that soon.

[kaneplusplus]

That would be great but there's not a big hurry. I probably won't get to this until January.