Lambda the Ultimate

Can Abstract State Machines Be Useful in Language Theory? Yuri Gurevich; Margus Veanes; Charles Wallace.

The abstract state machine (ASM) is a modern computation model. ASMs and ASM based tools are used in academia and industry, albeit in a modest scale. They allow you to give high-level operational semantics to computer artifacts and to write executable pecifications of software and hardware at the desired abstraction level. In connection to the 2006 conference on Developments in Language Theory, we point out several ways that we believe abstract state machines can be
useful to the DLT community.

I am not sure how useful this might be to LtU readers, but it is a nice introudction to ASMs.

Among the topics discussed are: concurrency, non-determinism, the notion of Universality (e.g., "Turing completenss") and the executability of the ASM notation (i.e., AsmL).

SANTA CLARA, CALIF. November 13, 2006 Sun Microsystems, Inc. (NASDAQ: SUNW), the creator and leading advocate of Java technology, today announced it is releasing its implementations of Java technology as free software under the GNU General Public License version two (GPLv2). Available today are the first pieces of source code for Sun's implementation of Java Platform Standard Edition (Java SE) and a buildable implementation of Java Platform Micro Edition (Java ME). Details are available at: http://www.sun.com/opensource/java.

A bold move, as Tim O'Reilly says? You be the judge.

Second Life Faces Threat to its Virtual Economy

Groups of Second Life content creators were gathering digitally Tuesday to protest the dissemination of a program they worry could badly damage the virtual world's nascent economy.

The controversy gathered steam Monday when Linden Lab, which publishes Second Life, posted a blog alerting residents of the virtual world to the existence of a program or bot called CopyBot, which allows someone to copy any object in Second Life. That includes goods such as clothing that people purchase for their in-world avatars, and even the virtual PCs that computer giant Dell announced Tuesday it is going to sell in the digital world.

Related to this thread, especially my "Not Merely Predictable" post, as well as the various Lightweight Static Capabilities and Robust Composition threads. I'm absolutely convinced that a future language design will evolve to accomodate the development of distributed systems in which these kinds of issues are impossible to impose. Is it time to add an "object capability security" and/or "cooperation without vulnerability" (a great phrase from Mark Miller) category to LtU?

(I looked but didn't see any other references to this on LtU)

There is now a Haskell -> Javascript converter using the York Haskell Compiler's (YHC's) "core" format.

From the YHC Core page:

Yhc.Core is a simple core Haskell-like language, feature case statements, let statements, top level lambda's and data values. Much of the syntactic sugar present in Haskell has gone (list comprehensions, typeclasses, overloaded names, nested lambdas)

The strengths of Yhc.Core are:

* Simple representation of Haskell
* Relatively simple to relate Core to original Haskell
* Source locations are preseved
* Minimal name mangling
* Few syntactic forms

The weaknesses are:

* Yhc cannot compile Yhc Core files, format is write only (fix is being worked on)
* Types are not present (hard to fix, a lot of work)

An hour long presentation by Martin Odersky on The Scala Experiment is available on Google Video. Covers a lot of territory, including (naturally) integration of FP/OOP, Erlang style Actors, Components vs. APIs, ML Functors, mixins, self-types - to name a few. The video is fuzzy on the slides, so it helps to have the pdf of the slides handy.

I can't say that I groked all the implications of the ground covered, much less the exact syntax, but at least it gave me a better feel for some of the PL problems that the Scala project is trying to address.