List.rotor

WANTED

@@ -22,4 +22,3 @@ API docs:
 
 Builtins:
     * Str.substr-eq
-    * List.rotor

lib/Type/List.pod

@@ -537,6 +537,39 @@ prints
     3 1 2
     3 2 1
 
+=head2 method rotor
+
+    method rotor(*@cylce, Bool() :$partial)
+
+Returns a list of list, which each sublist is made of elements of the
+invocant.
+
+In the simplest case, C<@cycle> contains just one integer, in which case the
+invocant list is split into sublists with as many elements as the integer
+specifies. If C<:$partial> is True, the final chunk is included even if it
+doesn't satisfy the length requirement:
+
+    say ('a'..'h').rotor(3).join('|');              # a b c|d e f
+    say ('a'..'h').rotor(3, :partial).join('|');    # a b c|d e f|g h
+
+If the element of C<@cycle> is a L</type/Pair|Pair> instead, the key of the
+pair specifies the length of the return sublist, and the value the gap betwee
+sublists; negative gaps produce overlap:
+
+    say ('a'..'h').rotor(2 => 1).join('|');         # a b|d e|g h
+    say ('a'..'h').rotor(3 => -1).join('|');        # a b c|c d e|e f g
+
+If C<@cycle> contains more than element, C<rotor> cycles through it to find
+the number of elements for each sublist:
+
+    say ('a'..'h').rotor(2, 3).join('|');           # a b|c d e|f g
+    say ('a'..'h').rotor(1 => 1, 3).join('|');      # a|c d e|f
+
+Combining multiple cycles and C<:partial> also works:
+
+    say ('a'..'h').rotor(1 => 1, 3 => -1, :partial).join('|');
+                                                    # a|c d e|e|g h
+
 =head2 routine zip
 
     sub zip(List:D:, List:D:, ...) returns List:D