Merge branch 'f-#98-glimpse-paren'. Fixes #98. @hadley: PTAL.

- `glimpse()` shows nesting structure for lists (#98).

NAMESPACE

@@ -15,6 +15,7 @@ S3method(as_data_frame,table)
 S3method(as_data_frame,tbl_df)
 S3method(format_v,character)
 S3method(format_v,default)
+S3method(format_v,list)
 S3method(glimpse,data.frame)
 S3method(glimpse,default)
 S3method(glimpse,tbl)

R/glimpse.R

@@ -77,7 +77,21 @@ str_trunc <- function(x, max_width) {
 }
 
 format_v <- function(x) UseMethod("format_v")
+
 #' @export
 format_v.default <- function(x) format(x, trim = TRUE, justify = "none")
+
+#' @export
+format_v.list <- function(x) {
+  x <- lapply(x, format_v)
+  atomic <- vapply(x, length, integer(1L)) == 1L
+  x <- vapply(x, function(x) paste(x, collapse = ", "), character(1L))
+  x[!atomic] <- paste0("<", x[!atomic], ">")
+  if (length(x) == 1L)
+    x
+  else
+    paste0("[", paste(x, collapse = ", "), "]")
+}
+
 #' @export
 format_v.character <- function(x) encodeString(x, quote = '"')

tests/testthat/output/glimpse/all-50.txt

@@ -7,5 +7,5 @@ $ d (chr) "a", "b", NA
 $ e (fctr) a, b, NA
 $ f (date) 2015-12-10, 2015-12-11, NA
 $ g (time) 2015-12-09 10:51:35, 2015-12-09 10...
-$ h (list) 1, 2, NA
-$ i (list) 1, 2, 3, 4, 5, 6, NA
+$ h (list) [1, 2, NA]
+$ i (list) [[1, <2, 3>], <4, 5, 6>, NA]

tests/testthat/output/glimpse/all-70.txt

@@ -7,5 +7,5 @@ $ d (chr) "a", "b", NA
 $ e (fctr) a, b, NA
 $ f (date) 2015-12-10, 2015-12-11, NA
 $ g (time) 2015-12-09 10:51:35, 2015-12-09 10:51:36, NA
-$ h (list) 1, 2, NA
-$ i (list) 1, 2, 3, 4, 5, 6, NA
+$ h (list) [1, 2, NA]
+$ i (list) [[1, <2, 3>], <4, 5, 6>, NA]