* array.c: Improve and fix documentation for Array#dig

  [#11776]

* hash.c: ditto

* struct.c: ditto

* test_hash.rb: Add basic test for user defined `dig`.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52941 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 6 insertions, 3 deletions

diff --git a/array.c b/array.c
index 159dc8f7a4..dd14837b76 100644
--- a/array.c
+++ b/array.c
@@ -5535,13 +5535,16 @@ rb_ary_any_p(VALUE ary)
  * call-seq:
  *   ary.dig(idx, ...)                 -> object
  *
- * Extracts the nested array value specified by the sequence of <i>idx</i>
- * objects.
+ * Extracts the nested value specified by the sequence of <i>idx</i>
+ * objects by calling +dig+ at each step, returning +nil+ if any
+ * intermediate step is +nil+.
  *
  *   a = [[1, [2, 3]]]
  *
  *   a.dig(0, 1, 1)                    #=> 3
- *   a.dig(0, 0, 0)                    #=> nil
+ *   a.dig(1, 2, 3)                    #=> nil
+ *   a.dig(0, 0, 0)                    #=> NoMethodError, undefined method `dig' for 1:Fixnum
+ *   [42, {foo: :bar}].dig(1, :foo)    #=> :bar
  */
 
 VALUE