Adds rotor refs #1731

Author: JJ

doc/Type/Any.pod6

@@ -1261,6 +1261,37 @@ Coerces the invocant to a C<list> by applying
 its L«C<.list>|/routine/list» method and uses
 L«C<List.batch>|/type/List#method_batch» on it.
 
+=head2 method rotor
+
+Defined as:
+
+    multi method rotor(Any:D: Int:D $batch, :$partial)
+    multi method rotor(Any:D: *@cycle, :$partial)
+
+Groups the elements of the object in lists of C<$batch> elements.
+
+    say (3..9).rotor(3); # OUTPUT: «((3 4 5) (6 7 8))␤»
+
+With the C<:partial> named argument, it will also include lists that do not get
+to be the C<$batch> size:
+
+    say (3..10).rotor(3, :partial); # OUTPUT: «((3 4 5) (6 7 8) (9 10))␤»
+
+C<.rotor> can be called with an array of integers and pairs, which will be
+applied in turn. While integers will establish the batch size, as above,
+C<Pair>s will use the key as batch size and the value as number of elements to
+skip if it's positive, or overlap if it's negative.
+
+    say (3..11).rotor(3, 2 => 1, 3 => -2, :partial);
+    # OUTPUT: «((3 4 5) (6 7) (9 10 11) (10 11))␤»
+
+In this case, the first batch (ruled by an integer) has 3 elements; the second
+one has 2 elements (key of the pair), but skips one (the number 8); the third
+one has size 2 (because partials are allowed), and an overlap of 2 also.
+
+Please see also L<C<list.rotor>|/type/List#method_rotor> for examples applied to
+lists.
+
 =end pod
 
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