[O] Dynamic tangle target?

[Philip Hudson]

AFAICT :tangle takes only "yes", "no", or a literal pathname. How
might I dynamically generate a pathname for :tangle? I suppose what I
want is some kind of escape syntax for eval'ing a Lisp form, like
maybe:

    :tangle %(my-dynamic-filename-generator)

Sorry if I'm missing something basic and obvious; I'm new to tangling.
I've been looking for a few days and found nothing so far, and even
though I'm sure the answer is out there, it seemed like at this point
my best bet is just to ask the ML. Might the answer be something to do
with either declaring a variable or using noweb syntax? I'm pretty
much in the dark here.

-- 
Phil Hudson                   http://hudson-it.ddns.net
@UWascalWabbit                 PGP/GnuPG ID: 0x887DCA63