feat(r): Add basic set of function translations #483
Description
After #468 we can translate an R expression into a SedonaDB/DataFusion expression; however, a limited number of functions are available. To have this be useful we need a wider range of functions available:
- Basic arithmetic, equality, and string functions
- All the functions that exist in a given context's
FunctionSet(i.e., all the spatial functions)
The dplyr-funcs-* files here: https://github.com/apache/arrow/tree/main/r/R have a very similar translation idiom and a number of tests we can draw on to implement these. Once we have a solid test framework I am hoping LLMs will do a great job with this one.