Add `substrait_join()` - Githubissues

Ok, this mostly works, with some limitations:

library(substrait, warn.conflicts = FALSE)
library(dplyr, warn.conflicts = FALSE)

cities <- tibble::tibble(
  city = c("Halifax", "Lancaster", "Chicago"),
  country = c("Canada", "United Kingdom", "United States")
)

countries <- tibble::tibble(
  country = c("United States", "Canada", "United Kingdom", "Morroco"),
  continent = c("North America", "North America", "Europe", "Africa")
)

cities |> 
  duckdb_substrait_compiler() |> 
  inner_join(countries) |> 
  arrange(city) |> 
  collect()
#> # A tibble: 3 × 3
#>   city      country        continent    
#>   <chr>     <chr>          <chr>        
#> 1 Chicago   United States  North America
#> 2 Halifax   Canada         North America
#> 3 Lancaster United Kingdom Europe

^{Created on 2023-03-06 with reprex v2.0.2}

The limitations are:

Mutating using Arrow give incorrect column results (need to investigate...basically they're all just integer zeroes on the righthand side)
DuckDB doesn't support anti joins or full joins at all
DuckDB currently errors for a semi-join...I'm wondering if my assumption of concatenated left and right output fields doesn't apply to filtering joins.

I think this is ready for initial review, though (and I'll open tickets for the limitations when I've investigated a bit more).

voltrondata / substrait-r

Add `substrait_join()` #225