split(index) <- value now warns about recycling (#15)

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: piar
 Title: Price Index Aggregation
-Version: 0.8.1
+Version: 0.8.1.9001
 Authors@R: c(
     person("Steve", "Martin", role = c("aut", "cre", "cph"),
            email = "[email protected]",

R/split.piar_index.R

@@ -9,8 +9,8 @@
 #' all levels are kept.
 #' @param margin Either 'levels' to split over the levels of `x` (the default),
 #'  or 'time' to split over the time periods of `x`.
-#' @param value A list of values compatible with the splitting of `x`, recycled
-#' if necessary.
+#' @param value A list of values compatible with the splitting of `x`, or
+#' something that can be coerced into one, recycled if necessary.
 #' @param ... Further arguments passed to [`split.default()`].
 #'
 #' @returns
@@ -42,9 +42,13 @@ split.piar_index <- function(x, f, drop = FALSE, ...,
 #' @export
 `split<-.piar_index` <- function(x, f, drop = FALSE, ...,
                                  margin = c("levels", "time"), value) {
+  value <- as.list(value)
   margin <- match.arg(margin)
   ix <- split(seq_along(x[[margin]]), f, drop = drop, ...)
   n <- length(value)
+  if (n > 0L && length(ix) %% n != 0) {
+    warning("number of items to replace is not a multiple of replacement length")
+  }
   j <- 0
   if (margin == "levels") {
     for (i in ix) {

tests/testthat/test-split.R

@@ -20,4 +20,10 @@ test_that("replacement works", {
   x <- as_index(matrix(1:6, 2))
   split(x, c(1, 1, 2), margin = "time") <- 1:2
   expect_equal(x, as_index(matrix(c(1, 1, 1, 1, 2, 2), 2)))
+
+  y <- x
+  split(y, factor(c(1, 1, 2), levels = character(0)), margin = "time") <- list()
+  expect_identical(x, y)
+
+  expect_warning(split(x, 1:3, margin = "time") <- 1:2)
 })