Jupyter Notebooks (Formerly IPython Notebooks) http://jupyter.org/ is kernel agnostic and can work with all the other languages also. I use it for R and Python myself. (For data work I still prefer RStudio or Python's Rodeo)
Breaker uses the same jkernel as IPython and backend of Jupyter.
Their are some "cell magics" for running different languages in individual blocks in a Jupyter notebook. I gave it a try in passing with javascript a while back and I remember there was a way to share variables through as well.
Unfortunately it looks like there is none for R or Julia, but perhaps they are installed by those specific packages, or their is some other way I don't know of.
The sharing objects thing seems like it would be fraught with errors and mismatches. R has a fundamentally different structuring than Python. From factors to numerics, and vectors.
If you can find an error in our implementation I would be happy to hear about it (ideally file an issue on github).
I am not an expert in R and I don't expect autotranslation to cover every case, but I think what we have is useful,
and I look forward to continuing to improve it based on community feedback.
Breaker uses the same jkernel as IPython and backend of Jupyter.