[cells-devel] Imperative vs. declarative

[Mike J. Bell]

Hey Kenny, I did a lot of thinking about what you said about
declarative vs. imperative.  I'm not sure what's the right
terminology, but I did finally see the light.

We've had problems in applications written in our framework when there
are multiple producers of one datum.  In a lot of cases (benign and
simple), it's been OK.  However, as soon as things get bigger, we put
a repeating pattern into our designs where a single controller
function will act as a gatekeeper, reading from multiple channels of
data, and forming the single producer for the difficult datum in the
previously intractable design.

I've thought about it quite a bit, and I've proved to myself that this
is equivalent to your declarative model, even if there are some slight
structural differences*.  So, in order for me to get from where I am
to where Cells is, all I need to do is instead of waiting for the
multiple producers issue to get out of hand and uncontrollable...just
nip it in the bud and don't allow it to begin with.  Then every piece
of data has only one producer.

Thanks again for talking with me about it!

Mike

* Speaking of structure, question for you.  Let's say you're declaring
a slot to be a function of a couple other slots in Cells.  How do you
know they exist?  I.e., where do you find your objects?  Do you have
like a database somewhere (hash of name->object or the like) that you
lookup to find things?  Are they all passed in at construction time? 
(I would imagine this wouldn't scale well at all).  Is there some
other scoping mechanism?

I'm not sure if Cells has any builtin support for finding the other
objects/slots that participate in Cells, or if you roll your own per
application...but I'd love to hear about how you solve it when *you*
write code.

-- 
Mike J. Bell on gmail