Shaping Systems with Seaside

Mark Watson writes...

if building web apps in Java, PHP, etc., is like carving something out of rock, Seaside is like using clay.

How to Design Large Erlang Systems

From the Erlang User's email list, the question "How do you design large Erlang programs?"

The answers and references from Erlang experts like Ulf Wiger and Joe Armstrong make interesting reading.

Another thread has mre useful design guidance, e.g. on composing state machines from Vance Shipley (and thus).

The Next Postscript

I can count the number of lines of Javascript I have written on, well, 20 hands. The core language makes sense to me, nevertheless: apparently Javascript sucks volumes (volume one and volume two).

My take on Javascript is that it could well be the next Postscript: over time, more of it will be generated than written by hand. Worse is better.

CalDAV

Mark Baker comments...

CalDAV is a red herring. We need calendar-specific operations in HTTP like we need a podcast-specific URI scheme.

This bothered me a fair bit too. Say I want to use WebDAV for authoring schematics of electronic circuits. The CalDAV precendent suggests I would begin a SchemDAV committee.

Makes little sense to me. On the other hand to make calendars or schematics more interoperable I think we should begin agreeing on what the HTTP verbs should mean relative to calendar or schematic resources.

Ideally we would agree what POST means when I send you an event description to your calendar. And that's probably the easiest one. We probably need to do other kinds of resources for and about calendars (and schematics) for searching, comparing, and calculating.

Given the recent ballyhoo of microformats vs. XML -- aren't we still dancing around the verbs? We need to agree on how to handle the verbs to get anywhere deep.

Termite: a Lisp for Distributed Computing

Update via email: Guillaume Germain expects to have a release of Termite in the next few weeks. End Update

Termite is a Lisp for distributed computing. (PDF paper and PDF presentation)

From the presentation...

In short: take Scheme, remove mutations, add isolated processes with mailboxes, add message sending and receiving operations and an addressing mechanism.

The bottom line is Termite is Erlang's distributed concurrency model ported to a dialect of Scheme that has been pared back to something like the sequential aspects of the Erlang language (chapters from Erlang book PDF).

Included in Termite are continuations that can support distributed process migration and macros. Continuations, macros, and closures allow Termite to be more amenable to discovering new abstractions than Erlang.

Termite is from the Gambit team at University of Montreal and runs on Gambit 4.

ATOM or WebDAV: The Rest of the Story?

I do not have a deep understanding of either ATOM or WebDAV but on the surface they seem to overlap in their publishing capabilities. ATOM's does not extend HTTP but WebDAV's does. On the other hand ATOM uses some less well-supported HTTP verbs anyway, so does this point matter?

The ATOM publishing protocol is generating a lot of enthusiasm, even saving us from the WS-xxx. So are these two protocols distinct? When would one be preferred over the other?

What about content-specific issues, like calendars. CalDAV extends WebDAV. Does ATOM have enough not to be extended like this? Should WebDAV be extended like this?