Lambda the Ultimate

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.

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).

This is the inaugural edition of Code Reads, a weekly discussion of some of the central essays, documents and texts in the history of software. This week we're talking about Frederick Brooks's The Mythical Man-Month. (OK, let's be honest: I'm talking about it. I'm hoping you, or you, or you, may want to, as well!

This is an ongoing series with Dijkstra's "Go To Statement Considered Harmful" coming up. This essay was mentioned here a few times, of course, so you might want to check the archives.

This item is not directly language related, but since you can win prizes, I thought I'd better let you guys know..

Omniscient debugging is old hat by now, but some of you might still enjoy this video of Bil Lewis talking about the subject. It includes snakes and things, believe it or not...

The first in a planned series of articles that introduces PowerPC ASM.
Assembly language for Power Architecture, Part 1: Programming concepts and beginning PowerPC instructions

Starting with this introduction to assembly language concepts and the PowerPC instruction set, this series of articles introduces assembly language in general and specifically assembly language programming for the POWER5.

It could just be me, but I think the ASM designers could've afforded to make this stuff a bit more human consummable - the preference is on the side of terseness:

li 0, 1
mr 3, 6
ld 6, 0(4)

Could be expressed a little cleaner as:

load R0, #1
load R3, R6
load R6, #0(R4)

No need for seperate instruction names for operations that are only different in how they load the data. And a clearer delineation of what is a register and what is a constant value. But then my bias for MCC68k is probably showing through. And the extra character for registers probably just makes higher level PL compiled code larger. (Oh well, easy enough to write a pretty viewer if one is so inclined.)

As spotted over on Haskell-cafe, Google Code Search is now available! Of course, someone immediately noticed that Haskell was not yet supported (see the drop down list on the advanced search page), so they asked. If your favourite language is missing (Ehud will be pleased, Ada is already there), ask!

Interestingly, Lua is already there. And I have never heard of Limbo before?

Via Mitch Wand's R6RS announcements mailing list:

I am extremely pleased to announce that a draft version of R6RS is now available at www.r6rs.org. A copy will also be posted on schemers.org.

The charter provides for a six-month public comment period. Therefore the editors, in consultation with the steering committee, have provided a mechanism for comment and discussion. Details are also at www.r6rs.org.

The comment period is now open and will continue until March 15, 2007.

The steering committee thanks the editors for their intensive work on the draft R6RS, and looks forward to the public comment period.

Enjoy!

For the Steering Committee,
--Mitch Wand

The program for the Dynamic Languages Symposium at OOPSLA is online.

The three invited talks look especially interesting. After the long nuclear winter caused by Java, it seems that we finally are entering a period of programming language renaissance.

I'm back... Going through my RSS feeds, two items caught my attention:

Tim Bray: Charles Nutter and Thomas Enebo, better known as “The JRuby Guys”, are joining Sun this month.

Jon Udell: Why argue about dynamic versus static languages when you can use both? Which discusses, among other things, why the first three versions of the IronPython compiler were written in Python, but today it's written in C#.

A recent story over at Ars Mathematica reminded me that I have seen a lot of interesting work in applying topology to programming language semantics.

The paper linked-to on Ars Mathematica is more about applications to software engineering (precise notion of refinement, but since implementations are the ultimate refinement of a specification, this is quite relevant to PLs as well). But there is a lot more work in this area! For those with a theoretical bent, there are a series of articles by John Tucker and Jeffery (Jeff) Zucker, for example Abstract versus Concrete Computation on Metric Partial Algebras (many more available from their respective web pages). Another thread that I like is the work of Abbas Edalat; he has written many papers relating topology, domain theory and computations in analysis. I am particularly fond of the work of Martin Escardo; the lecture notes on Mathematical foundations of functional programming with real numbers might interest a few people here. But as far as I am concerned (and Haskell fans might agree), his Magnum Opus is Synthetic topology of data types and classical spaces.