arrow

ARROW-14227: [R] Implement lubridate is.* methods

Implements `is.Date()`, `is.POSIXct()`, `is.timepoint()`, and `is.instant()` from the lubridate package.

There is also `lubridate::is.POSIXt()` and `lubridate::is.POSIXlt()`...these are a bit more niche and I thought they might be confusing if implemented here.

Another question I had while implementing this...can/should these return an `Expression$scalar()`? This isn't how the other `is.*()` functions are done but maybe this makes a difference?

``` r
library(arrow, warn.conflicts = FALSE)
library(lubridate, warn.conflicts = FALSE)
library(dplyr, warn.conflicts = FALSE)

test_date <- as.POSIXct("2017-01-01 00:00:11.3456789", tz = "Pacific/Marquesas")

test_df <- tibble::tibble(
  datetime = c(test_date, NA) + 1,
  date = c(as.Date("2021-09-09"), NA)
)

RecordBatch$create(test_df) %>%
  mutate(is.POSIXct(datetime), is.POSIXct(date)) %>%
  collect()
#> # A tibble: 2 × 4
#>   datetime            date       `is.POSIXct(datetime)` `is.POSIXct(date)`
#>   <dttm>              <date>     <lgl>                  <lgl>
#> 1 2017-01-01 00:00:12 2021-09-09 TRUE                   FALSE
#> 2 NA                  NA         TRUE                   FALSE

RecordBatch$create(test_df) %>%
  mutate(is.Date(datetime), is.Date(date)) %>%
  collect()
#> # A tibble: 2 × 4
#>   datetime            date       `is.Date(datetime)` `is.Date(date)`
#>   <dttm>              <date>     <lgl>               <lgl>
#> 1 2017-01-01 00:00:12 2021-09-09 FALSE               TRUE
#> 2 NA                  NA         FALSE               TRUE

RecordBatch$create(test_df) %>%
  mutate(is.instant(datetime), is.instant(date)) %>%
  collect()
#> # A tibble: 2 × 4
#>   datetime            date       `is.instant(datetime)` `is.instant(date)`
#>   <dttm>              <date>     <lgl>                  <lgl>
#> 1 2017-01-01 00:00:12 2021-09-09 TRUE                   TRUE
#> 2 NA                  NA         TRUE                   TRUE

RecordBatch$create(test_df) %>%
  mutate(is.timepoint(datetime), is.timepoint(date)) %>%
  collect()
#> # A tibble: 2 × 4
#>   datetime            date       `is.timepoint(datetime)` `is.timepoint(date)`
#>   <dttm>              <date>     <lgl>                    <lgl>
#> 1 2017-01-01 00:00:12 2021-09-09 TRUE                     TRUE
#> 2 NA                  NA         TRUE                     TRUE
```

<sup>Created on 2021-11-02 by the [reprex package](https://reprex.tidyverse.org) (v2.0.1)</sup>

Closes #11592 from paleolimbot/lubridate-is-methods

Authored-by: Dewey Dunnington <dewey@fishandwhistle.net>
Signed-off-by: Jonathan Keane <jkeane@gmail.com>