WIP: PoC for storing pure polars calls in attributes

[etiennebacher]

Close #96

Example:

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

iris |> 
  as_polars_df() |> 
  select(starts_with(c("Sep", "Pet"))) |> 
  mutate(x = (Petal.Length / Petal.Width) > 3) |> 
  filter(between(Sepal.Length, 4.5, 6.5), Petal.Length < 5) |> 
  head() |> 
  show_query()
#> Pure polars expression:
#> 
#> <data>$
#>   select(c("Sepal.Length", "Sepal.Width", "Petal.Length", "Petal.Width"))$
#>   with_columns(x = p$col("Petal.Length")$div(p$col("Petal.Width"))$gt(3))$
#>   filter(p$col("Sepal.Length")$is_between(lower_bound = 4.5, upper_bound = 6.5, closed = "both"), p$col("Petal.Length")$lt(5))$
#>   head(n = 6L)

TODO:

• wrap up, pass tests
• prepare snapshot tests
• refactor, add comments
• potentially write a vignette for future self + interested readers
• wrong query for bind_cols_polars()
• class of original data shouldn't change

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

pl_relig_income <- as_polars_df(tidyr::relig_income)

class(pl_relig_income)
#> [1] "RPolarsDataFrame"

x <- pl_relig_income |>
  arrange(drat)

class(pl_relig_income)
#> [1] "tidypolars"       "RPolarsDataFrame"

[eitsupi]

It may helpful the tidyquery package's code.
https://github.com/ianmcook/tidyquery

The tidyquery package generates a dplyr query string from an SQL string and executes the actual dplyr query, but I believe the query to be displayed and the query to be executed were constructed separately (rather than being evaluated as is after the string is assembled)