Tweak extend to include {Inf} separately if endpoint is like Inf)

R/breaks-impl.R

@@ -81,20 +81,19 @@ maybe_extend <- function (breaks, x, extend) {
 
 
 extend_breaks <- function (breaks) {
-  if (length(breaks) == 0 || breaks[1] > -Inf) {
-    left <- attr(breaks, "left")
+  left <- attr(breaks, "left")
+  # we add a break if the first break is above -Inf *or* if it is (-Inf. ...
+  if (length(breaks) == 0 || breaks[1] > -Inf || ! left[1]) {
     breaks <- c(-Inf, breaks) # deletes attributes inc class
     breaks <- create_breaks(breaks, c(TRUE, left))
   }
-  attr(breaks, "left")[1] <- TRUE
 
-  if (breaks[length(breaks)] < Inf) {
-    left <- attr(breaks, "left")
+  left <- attr(breaks, "left")
+  # add a break if the last break is finite, or if it is ..., +Inf)
+  if (breaks[length(breaks)] < Inf || left[length(left)]) {
     breaks <- c(breaks, Inf) # deletes attributes inc class
     breaks <- create_breaks(breaks, c(left, FALSE))
   }
-  left <- attr(breaks, "left")
-  attr(breaks, "left")[length(left)] <- FALSE
 
   return(breaks)
 }

R/chop.R

@@ -38,11 +38,12 @@ NULL
 #'  [lbl_numerals()].
 #'
 #' If `extend` is `TRUE`, intervals will be extended to \code{[-Inf,
-#' min(breaks))} and \code{(max(breaks), Inf]}, unless those endpoints are
-#' already infinite. If `extend` is `NULL` (the default), intervals will
-#' be extended only if the data is outside their range.
+#' min(breaks))} and \code{(max(breaks), Inf]} (unless the first and last
+#' endpoints are already `[-Inf` and `Inf]` respectively). If `extend` is `NULL`
+#' (the default), intervals will be extended only if the data is outside their
+#' range.
 #'
-#' `NA` values in `x`, and values which are outside the (extendeD) endpoints,
+#' `NA` values in `x`, and values which are outside the (extended) endpoints,
 #' return `NA`.
 #'
 #' Note that `chop`, like all of R, uses binary arithmetic. Thus, numbers may

tests/testthat/test-chop.R

@@ -27,10 +27,10 @@ test_that("NA, NaN and Inf", {
 
   x <- c(-Inf, 1, Inf)
   # if extend is NULL, we should ensure even Inf is included
-  r <- chop(x, brk_right(-Inf, close_end = FALSE), labels = "a")
-  expect_equivalent(r, factor(c("a", "a", "a"), levels = "a"))
-  r <- chop(x, brk_left(Inf, close_end = FALSE), labels = "a")
-  expect_equivalent(r, factor(c("a", "a", "a"), levels = "a"))
+  r <- chop(x, brk_right(-Inf, close_end = FALSE), labels = c("-Inf", "a"))
+  expect_equivalent(r, factor(c("-Inf", "a", "a"), levels = c("-Inf", "a")))
+  r <- chop(x, brk_left(Inf, close_end = FALSE), labels = c("a", "Inf"))
+  expect_equivalent(r, factor(c("a", "a", "Inf"), levels = c("a", "Inf")))
 
   # otherwise, we respect close_end = FALSE
   r <- chop(x, brk_right(c(-Inf, Inf), close_end = FALSE), labels = "a",