basic auto-naming

NAMESPACE

@@ -100,6 +100,7 @@ importFrom(checkmate,test_subset)
 importFrom(checkmate,vname)
 importFrom(cli,cat_line)
 importFrom(cli,cli_abort)
+importFrom(cli,cli_inform)
 importFrom(cli,cli_vec)
 importFrom(cli,cli_warn)
 importFrom(cli,format_message)

R/epi_df.R

@@ -256,9 +256,34 @@ as_epi_df.epi_df <- function(x, ...) {
 #'   (stored in its attributes); if this fails, then the current day-time will
 #'   be used.
 #' @importFrom rlang .data
+#' @importFrom cli cli_inform
 #' @export
 as_epi_df.tbl_df <- function(x, geo_type, time_type, as_of,
-                             additional_metadata = list(), ...) {
+                             additional_metadata = list(),
+                             substitutions = NULL, ...) {
+  # possible standard substitutions
+  if (!("time_value" %in% names(x))) {
+    if (("forecast_date" %in% names(x)) && ("target_date" %in% names(x))) {
+      cli_abort("both `forecast_date` and `target_date` are present without a `time_value`
+column, so it is ambiguous which to choose as `time_value`.")
+    }
+    name_substitutions <- substitutions %||% c(
+      time_value = "date",
+      time_value = "forecast_date",
+      time_value = "target_date",
+      time_value = "dates",
+      time_value = "time_values",
+      time_value = "forecast_dates",
+      time_value = "target_dates"
+    )
+    x <- tryCatch(x %>% rename(any_of(name_substitutions)),
+      error = function(cond) {
+        cli_abort("There are multiple `time_value` candidate columns.
+Either `rename` on yourself or drop some.")
+      }
+    )
+    cli_inform("inferring `time_value` column.")
+  }
   if (!test_subset(c("geo_value", "time_value"), names(x))) {
     cli_abort(
       "Columns `geo_value` and `time_value` must be present in `x`."

tests/testthat/test-epi_df.R

@@ -46,6 +46,22 @@ test_that("as_epi_df errors when additional_metadata is not a list", {
   )
 })
 
+test_that("as_epi_df works for nonstandard input", {
+  tib <- tibble::tibble(
+    x = 1:10, y = 1:10,
+    date = rep(seq(as.Date("2020-01-01"), by = 1, length.out = 5), times = 2),
+    geo_value = rep(c("ca", "hi"), each = 5)
+  )
+  expect_message(expect_no_error(tib_epi_df <- tib %>% as_epi_df()))
+
+  tib <- tib %>% rename(forecast_date = date)
+  expect_message(expect_no_error(tib_epi_df <- tib %>% as_epi_df()))
+  tib %>% rename(any_of(name_substitutions))
+
+  tib <- tib %>% mutate(target_date = 20 + forecast_date)
+  expect_error(tib_epi_df <- tib %>% as_epi_df())
+})
+
 # select fixes
 
 tib <- tibble::tibble(