Document roundrobin

... wantonly stealing from the specs

lib/Type/List.pod

@@ -516,14 +516,31 @@ by the signature:
         say "Name: $name;   Zip code: $zip";
     }
 
-By default the C<zip> function reads to the end of the shortest list,
-but a short list may always be extended arbitrarily by putting C<*>
-after the final value, which replicates the final value as many times
-as necessary.  If instead of supplying a default value for short lists,
-you just wish to skip missing entries, use C<roundrobin> instead:
+By default the C<zip> function reads to the end of the shortest list, but a
+short list may always be extended arbitrarily by putting C<*> after the
+final value, which replicates the final value as many times as necessary.
+If instead of supplying a default value for short lists, you just wish to
+skip missing entries, use L<roundrobin|/type/List#sub_roundrobin> instead:
 
     for roundrobin(@queue1; @queue2; @queue3) -> $next {
         ...
     }
 
+=head2 sub roundrobin
+
+    multi roundrobin(List:D: --> Parcel)
+
+C<roundrobin> is very similar to L<zip|/type/List#routine_zip>.  The
+difference is that C<roundrobin> will not stop on lists that run out of
+elements but simply skip any undefined value:
+
+    my @a = 1;
+    my @b = 1..2;
+    my @c = 1..3;
+    for roundrobin(@a; @b; @c) -> $x { $x.say }
+
+will display the following values: C<1, 1, 1, 2, 2, 3>
+
 =end pod
+
+# vim: expandtab shiftwidth=4 ft=perl6