Proof of concept passing data around between Python and R

[nealrichardson]

To do:

• Make the reticulate package optional
• Actually run the tests
• Confirm the r_to_py works
• Update CI to install and test appropriately
• Add support for RecordBatch (will do Table/ChunkedArray later)

[pitrou]

@nealrichardson I made two changes on my branch:

• rename export_to_c (resp. import_from_c) to _export_to_c (resp. _import_from_c)
• add the same methods for record batches (i.e. on the pa.RecordBatch class)

[codecov]

Codecov Report

Merging #5 into c-data-interface-impl will decrease coverage by 12.12%.
The diff coverage is 0%.

@@                    Coverage Diff                     @@
##           c-data-interface-impl       #5       +/-   ##
==========================================================
- Coverage                   89.6%   77.47%   -12.13%     
==========================================================
  Files                        102       61       -41     
  Lines                       6636     4604     -2032     
  Branches                    1501        0     -1501     
==========================================================
- Hits                        5946     3567     -2379     
- Misses                       679     1037      +358     
+ Partials                      11        0       -11

Impacted Files	Coverage Δ
r/src/arrow_types.h	96% <ø> (ø)
r/R/arrow-package.R	82.35% <0%> (ø)
r/R/arrowExports.R	73.52% <0%> (ø)
r/src/py-to-r.cpp	0% <0%> (ø)
r/R/py-to-r.R	0% <0%> (ø)
r/src/arrowExports.cpp	73.27% <0%> (ø)
js/src/util/fn.ts
js/src/builder/index.ts
js/src/enum.ts
js/src/Arrow.node.ts
... and 159 more

---

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[pitrou]

@ursabot build

[nealrichardson]

@pitrou would you mind rebasing this? I don't know how to resolve the cpp conflicts. For the r/R/arrow-package.R conflict, we want to keep all of the lines that conflict; order doesn't matter.

[pitrou]

I've pushed changes. Unfortunately I couldn't check that this compiles.

[nealrichardson]

Fixed.

How do you want to proceed with this? Do you want to merge this into your c-data-interface-impl branch? Or merge that first and then I can make a followup JIRA for my branch?

[pitrou]

Thanks for the fix. I think I'll merge into my PR.

[nealrichardson]

I see this is merged but I'm not seeing the changes show up in apache#5608, is that expected?

[pitrou]

Uh, you're right. I must have messed something. Let me try again.