Re: Continuation webapps

"Anton van Straaten" <anton@appsolutions.com> writes:

> Nic Ferrier <nferrier@tapsellferrier.co.uk> wrote:
> 
>
> ViaWeb/Yahoo Stores.  You've probably seen "Beating the Averages":
>
> http://www.paulgraham.com/lwba.html
>
> ...but see also the second link on the above page, to the BBN talk, in
> particular the section entitled "Closures Simulate Subroutines".

But famously Yahoo got rid of the LISP. Maybe they had scaling
problems?  /8->


> 2.  *All* webapps have continuations.  "State of the art" webapps are
> currently written in continuation-passing style.  A simple URL is a
> continuation.  Continuations in most webapps are manually encoded in the
> form of URLs, HTML forms submitted as HTTP requests, and (sometimes)
> server-side session objects.  The real question is whether the continuatio
ns
> are handled manually (most existing webapps) or automatically (some Scheme
> webapps).

I don't agree. A simple URL defines a resource. I can't see that it is
a continuation unless you wrap one round it.

You can of course encode forward and back references in page content
(and parameters). But this is just more state and almost always
unnecessary.


> 4.  With serializable continuations in e.g. SISC and Gambit, you can also
> store the continuation-based state in the backend.

Yes. But that doesn't necessarily help. What is the state? Is it an
ongoing SQL transaction? Can it be adopted by another server that
doesn't have the same connection to the database?

No. It is very imperfect.


--
Nic Ferrier
http://www.tapsellferrier.co.uk