Lambda the Ultimate

Ning is a new free online service for building and using social applications.

The apps are built using PHP and a simple XML-vocabulary based DSL called XNHTML.

As I've been saying for a long time here and elsewhere, it's all about programmability these days, and as the Ning folks realise DSLs are a very good technique for achieving end-user programmability.

Seems to me they could have gone the extra mile, and eliminated the need for PHP altogether, but I guess that would be asking for too much...

Hooray for the winners and judges!!
Link

On many occasions on this site we've discussed embedding a dynamic type checking scheme in a statically typed language using a Univ type. On many of these occasions, it's been suggested that this is an in-principle solution that would never be usable in practice, Turing tar-pit, etc., etc. Well, someone decided to put their money where our mouths are, and now we have Dynaml.

I've only briefly looked at the tutorial, but this definitely goes a long way toward demonstrating a plausible Univ embedding of a dynamic type system. Of course, I'd be curious to hear what everyone else thinks...

(from the caml weekly news...)

CODeDOC 2002 was a collection of 'software art' projects. One work, W. Bradford Paley's CodeProfiles.java [requires Java support in browser], is particularly interesting because it shows three different ways in which code is "read". The first, and simplest, is a linear scan through the source (the amber highlighting). Second is the sequence in which code was written (white). Third is the execution flow as the program executes.

It's striking how unrelated these three sequences are. Since temporal sequencing lies at the heart of programming, this struck me as worrying. But then, how should they be related? How should the program's structure and creation be related to its temporal flow? And, of course, how does this relate to the language chosen?

For example: if the code were purely declarative then why would there be any correlation between execution and layout? Is my intuition about the importance of any simple relationship between these flows misguided?

Anyway, it is certainly pretty.

Taken out of order:

From Ryan Kusnery's weird languages page:

The day that someone writes, in Malbolge, a program that simply copies its input to it's output, is the day my hair spontaneously turns green. It's the day that elephants are purple and camels fly, and a cow can fit through a needle's eye.

earlier:

I've succeeded in writing a Malbolge program that copies its input to its output. Since some of it is non-printing, here it is uu-encoded...

In addition the page contains a proof of Turing Completeness (of a slight modification of the language), and suggestions on how it could be made harder.

Inspired by Daniel Horn's Obfuscated V contest in the fall of 2004, we hereby announce an annual contest to write innocent-looking C code implementing malicious behavior. In many ways this is the exact opposite of the Obfuscated C Code Contest: in this contest you must write code that is as readable, clear, innocent and straightforward as possible, and yet it must fail to perform at its apparent function. To be more specific, it should do something subtly evil.

I wasn't aware of this contest. This concept sounds like fun, the idea being to write source code that easily passes visual inspection by other programmers.

The challenge for the first UCC is to write a simple program that performs some basic image-processing operation, for example smoothing or resampling, but manages to conceal a unique imperceptible fingerprint in each image it outputs.

Jacob Matthews, of PLT fame, is writing a blog currently covering PLDI. It's an interesting and amusing read; check it out!

As Slashdot observes, PHP was born 10 years ago on June 8th 1995.

It's had its knockers, but it's running this site...

A well done set of Python challenges.

Some solutions can be found here, if you need help getting started...

Chris Coyne's Context Free Design Grammar was just mentioned by Perry Wagle on the #haskell irc channel. It's a beautiful use of simple concepts in a surprising manner. If you haven't seen the examples, you're missing out.

Chris mentions on the download page that's he's gotten a lot of hits because he's linked from SCIgen, the recently slashdotted automatic CS paper generation project at MIT. Even more amazing, One of their randomly generated papers was accepted.