rkm1000 wrote:
Hi all,
I decided to take a shot at cells and allegrocache.
This is pretty scary, two hours earlier I got invited to talk at ILC
2008 and thought I would do RDFCells.
I started by adding
(:metaclass db.ac:persistent-class) to model-object.
Committing changes
revealed that allegocache doesn't know how to encode cells::cells or
cells::c-dependent. I expected that would be the case.
Allegrocache will encode structures when provided a method encode-
object, but I've run into a couple of problems. Encoding the caller-
store member of a cells struct leads to a stack overflow. I imagine
allegrocache handles circular references when dealing with collections
of CLOS objects, but it doesn't appear to do so with encode-object and
structs. At least that is what I'm thinking is the problem for now...
Yeah, you have to manage circularities yourself, but one does the same
when using print/read for serialization, I guess the standard is to
force the client to handle circs.
The other problem is with the rule member of c-ruled. Is serializing a
function even possible?
Either use EVAL or a diabolical trick: for any lambda you want to store,
define a persistent class with a slot with an initform producing that
lambda. AC has to convert that to an initform-function, which you can
then call to get lambdas. Sick. If you have a suitable Franz license,
just use eval. The other issue is getting the form defining the lambda
saved. I think Cells keeps rules in symbolic form in a slot for
debugging purposes, so you just need to make sure that gets stored.
I have suspicions about solutions to both of these, but before I bloody
my forehead I thought I would ask if anyone has attempted to use
allegrocache with cells and what their experiences have been.
I did AllegroStore+Cells. At the time Cells was mop-based and Astore
played nice with the MOP. Went incredibly well, but I did have to add a
layer of code to achieve the functionality I desired. Probably a full
few weeks effort.
Well worth it and quite exciting to see (a) a self-updating database and
(b) seamless auto-update of any view of the DB as the DB changed
underneath it.
kt
_______________________________________________
cells-devel site list
[email protected]
http://common-lisp.net/mailman/listinfo/cells-devel
