R/cur-context.R

In tidytable: Tidy Interface to 'data.table'

#' Context functions
#'
#' @description
#' These functions give information about the "current" group.
#'
#' * `cur_data()` gives the current data for the current group
#' * `cur_column()` gives the name of the current column (for use in `across()` only)
#' * `cur_group_id()` gives a group identification number
#' * `cur_group_rows()` gives the row indices for each group
#'
#' Can be used inside `summarize()`, `mutate()`, & `filter()`
#'
#'
#' @examples
#' df <- data.table(
#'   x = 1:5,
#'   y = c("a", "a", "a", "b", "b")
#' )
#'
#' df %>%
#'   mutate(
#'     across(c(x, y), ~ paste(cur_column(), .x))
#'   )
#'
#' df %>%
#'   summarize(data = list(cur_data()),
#'             .by = y)
#'
#' df %>%
#'   mutate(group_id = cur_group_id(),
#'          .by = y)
#'
#' df %>%
#'   mutate(group_rows = cur_group_rows(),
#'          .by = y)
#' @name context
NULL

#' @export
#' @rdname context
cur_column <- function() {
  abort("cur_column() should only be used inside across()")
}

#' @export
#' @keywords internal
#' @inherit context title description examples
cur_column. <- cur_column

#' @export
#' @rdname context
cur_data <- function() {
  abort("cur_data() should only be used inside tidytable verbs")
}

#' @export
#' @keywords internal
#' @inherit context title description examples
cur_data. <- cur_data

#' @export
#' @rdname context
cur_group_id <- function() {
  abort("cur_group_id() should only be used inside tidytable verbs")
}

#' @export
#' @keywords internal
#' @inherit context title description examples
cur_group_id. <- cur_group_id

#' @export
#' @rdname context
cur_group_rows <- function() {
  abort("cur_group_rows() should only be used inside tidytable verbs")
}

#' @export
#' @keywords internal
#' @inherit context title description examples
cur_group_rows. <- cur_group_rows