R interface returning structured data

[graybeal]

Is your feature request related to a problem? If so please describe.
Some data may be organized structurally, e.g. as an array of observations, or some request may be fulfilled with a structured collection of data.

Describe the solution you'd like
A clear and concise description of what you want to happen.
Consider designing a rich R interface that returns highly structured data according to a well-defined standard.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
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Josef showed some early conceptual drawings of this idea. Not clear if it is immediately useful, but some of the ideas may be integrated in the developed R code.

[johardi]

The conceptual drawing: https://docs.google.com/presentation/d/1yswvKHRlUMkbeC0DoO-W_RNrRMd_r7k4OChhGfapeck/edit?usp=sharing