Type unions in D

[language_fan]

Wed, 16 Sep 2009 12:41:06 +0200, Fawzi Mohamed thusly wrote:

> On 2009-09-16 02:40:02 +0200, Justin Johansson
> <procode at adam-dott-com.au> said:

>> A colleague of mine is suggesting that I really do take a closer look
>> at D2 now but I'm not sure that I'm ready to go standing on the
>> bleading bleading (the blood doesn't clot) edge just right yet. :-(
>> 
>> JJ
> 
> Tango has variant (tango.core.Variant), and is D1, if that could be an
> option for you.

Do the various variant structures presented here support recursive type 
definitions such as lists? Is this done efficiently?