* enum.c: Make Enumerable#chunk with no block return

an Enumerator [#2172]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56342 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Wed Oct  5 03:24:55 2016  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
+
+	* enum.c: Make Enumerable#chunk with no block return
+	  an Enumerator [#2172]
+
 Wed Oct  5 01:19:45 2016  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* internal.h (ST2FIX): new macro to convert st_index_t to Fixnum.

NEWS

@@ -42,6 +42,8 @@ with all sufficient information, see the ChangeLog file or Redmine
 
   * Enumerable#sum  [Feature #12217]
   * Enumerable#uniq  [Feature #11090]
+  * Enumerable#chunk called without a block now return an Enumerator
+    [Feature #2172]
 
 * Enumerator::Lazy
 

enum.c

@@ -2995,14 +2995,14 @@ chunk_i(RB_BLOCK_CALL_FUNC_ARGLIST(yielder, enumerator))
  *      }
  *    }
  *
+ *  If no block is given, an enumerator to `chunk` is returned instead.
  */
 static VALUE
 enum_chunk(VALUE enumerable)
 {
     VALUE enumerator;
 
-    if (!rb_block_given_p())
-	rb_raise(rb_eArgError, "no block given");
+    RETURN_SIZED_ENUMERATOR(enumerable, 0, 0, enum_size);
 
     enumerator = rb_obj_alloc(rb_cEnumerator);
     rb_ivar_set(enumerator, rb_intern("chunk_enumerable"), enumerable);

test/ruby/test_enum.rb

@@ -611,6 +611,12 @@ class TestEnumerable < Test::Unit::TestCase
 
     e = @obj.chunk {|elt| :_foo }
     assert_raise(RuntimeError) { e.to_a }
+
+    e = @obj.chunk.with_index {|elt, i| elt - i }
+    assert_equal([[1, [1, 2, 3]],
+                  [-2, [1, 2]]], e.to_a)
+
+    assert_equal(4, (0..3).chunk.size)
   end
 
   def test_slice_before