Export is_selector_registered() function

[ddsjoberg]

Export a utility that is the top section of .generic_selector(): a predicate indicating whether or not the table/var_info data has been registered.

.generic_selector <- function(variable_column, select_column, select_expr, fun_name) {
  # ensuring the proper data has been scoped to use this function
  if (!exists("df_var_info", envir = env_variable_type) ||
      (exists("df_var_info", envir = env_variable_type) &&
       !all(c(variable_column, select_column) %in% names(env_variable_type$df_var_info)))) {
    cli_alert_danger("Cannot use selector '{fun_name}()' in this context.")
    stop("Invalid syntax", call. = FALSE)
  }

  # selecting the variable from the variable information data frame
  env_variable_type$df_var_info %>%
    dplyr::select(all_of(c(variable_column, select_column))) %>%
    dplyr::filter(stats::complete.cases(.)) %>%
    dplyr::filter({{ select_expr }}) %>%
    dplyr::pull(all_of(variable_column)) %>%
    unique()
}

is_selector_registered <- function(variable_column, select_column) {
  !exists("df_var_info", envir = env_variable_type) ||
      (exists("df_var_info", envir = env_variable_type) &&
       !all(c(variable_column, select_column) %in% names(env_variable_type$df_var_info)))
}

[larmarange]

Ok. Note: the name should start with a dot as the other helpers

[larmarange]

Please have a look at #164

Note that I have inverted the condition: to be registered, you need both column in env_variable_type$df_var_info