obj_sum() returns short version in attribute

R/type-sum.R

@@ -69,10 +69,13 @@ vec_ptype_abbr.pillar_empty_col <- function(x, ...) {
 #' As of pillar v1.6.1, the default method forwards to [vctrs::vec_ptype_abbr()]
 #' for vectors and to [type_sum()] for other objects.
 #' Previous versions always forwarded to [type_sum()].
+#' An attribute named `"short"` in the return value will be picked up by
+#' the [pillar_shaft()] method for lists, and used if space is limited.
 #'
 #' @examples
 #' obj_sum(1:10)
 #' obj_sum(matrix(1:10))
+#' obj_sum(data.frame(a = 1))
 #' obj_sum(Sys.Date())
 #' obj_sum(Sys.time())
 #' obj_sum(mean)
@@ -87,7 +90,16 @@ obj_sum.default <- function(x) {
   if (!vec_is(x)) {
     type_sum(x)
   } else {
-    paste(vec_ptype_abbr(x, suffix_shape = FALSE), size_sum(x))
+    abbr <- vec_ptype_abbr(x, suffix_shape = FALSE)
+
+    out <- paste(abbr, size_sum(x))
+    if (is.array(x)) {
+      short <- paste0(abbr, "[", cli::symbol$ellipsis, "]")
+    } else {
+      short <- abbr
+    }
+
+    structure(out, short = short)
   }
 }
 

tests/testthat/test-obj-sum.R

@@ -19,6 +19,8 @@ test_that("data frames and common data vectors have size summary", {
 
   expect_obj_sum_is_ptype <- function(x) {
     obj_sum <- obj_sum(x)
+    attr(obj_sum, "short") <- NULL
+
     ptype <- vec_ptype_abbr(x, suffix_shape = FALSE)
 
     expect_equal(obj_sum, !!paste_with_space_if_needed(ptype, size_sum(x)))
@@ -32,9 +34,35 @@ test_that("data frames and common data vectors have size summary", {
   expect_obj_sum_is_ptype(Sys.time() - Sys.time() + 1:3)
   expect_obj_sum_is_ptype(as.POSIXlt(Sys.time() + 1:3))
   expect_obj_sum_is_ptype(list(1, 2:3))
+  expect_obj_sum_is_ptype(matrix(1:10, ncol = 2))
+  expect_obj_sum_is_ptype(Titanic)
   expect_obj_sum_is_ptype(as_override_size_sum(1:3))
 })
 
+test_that("object summary has short version", {
+  local_override_size_sum()
+
+  expect_obj_sum_short_is_ptype <- function(x, suffix = "") {
+    obj_sum <- attr(obj_sum(x), "short")
+
+    ptype <- vec_ptype_abbr(x, suffix_shape = FALSE)
+
+    expect_equal(obj_sum, !!paste0(ptype, suffix))
+  }
+
+  expect_obj_sum_short_is_ptype(mtcars)
+  expect_obj_sum_short_is_ptype(factor(1:3))
+  expect_obj_sum_short_is_ptype(ordered(1:3))
+  expect_obj_sum_short_is_ptype(Sys.Date() + 1:3)
+  expect_obj_sum_short_is_ptype(Sys.time() + 1:3)
+  expect_obj_sum_short_is_ptype(Sys.time() - Sys.time() + 1:3)
+  expect_obj_sum_short_is_ptype(as.POSIXlt(Sys.time() + 1:3))
+  expect_obj_sum_short_is_ptype(list(1, 2:3))
+  expect_obj_sum_short_is_ptype(matrix(1:10, ncol = 2), paste0("[", cli::symbol$ellipsis, "]"))
+  expect_obj_sum_short_is_ptype(Titanic, paste0("[", cli::symbol$ellipsis, "]"))
+  expect_obj_sum_short_is_ptype(as_override_size_sum(1:3))
+})
+
 
 # type_sum ----------------------------------------------------------------