Lambda the Ultimate

This document describes how Multidimensional Expressions (MDX) for Microsoft SQL Server 2005 Beta 2 can be applied to common business problems.

Given the interest in database integration exhibited in the past, I guess this may be of interest to some readers.

MDX is the server-based calculation engine provided by SQL Server's Analysis Services. MDX scripts appear to execute like programs, however the MDX script does not really "run." It is a declared set of commands that are always in effect. The contents of the cube are always consistent with the script. The scripting language is explained along with examples.

You might call it declarative programming...

Since we are having a slow week, I thought it might be a good idea to mention three interesting threads from the discussion group. Most regulars read the discussion group, but not everyone is aware of it, and we are still working on an RSS feed for new discussion group messages. So, in case you missed them, you might want to check out,

1. Understanding continuations.
2. Explaining monads.
3. Why type systems are interesting (this is a long thread, so consider starting a new one if you want to move the discussion in a new direction).

This is a bit offtopic, but Francis Crick was an esteemed man of science and we should all be saddened to hear of his death.

Crick co-discovered the the structure and properties of DNA in 1953, along with James Watson.

His work leading to the understanding of the genetic code is, however, more closely related to our areas of interest. These classic experiments were an astonishing example of scientific discovery at its best.

In recent years Crick was interested in the questions of neurobiology, and published the provocative book Astonishing Hypothesis which tackled the question of human consciousness.

In a forum dedicated to programming languages is it is easy to get carried away, and forget that choosing a programming language for a project is not just about finding the best or most expressive language possible, but often very much dependent on the platform for which the software is developed.

An interesting blog post about web applications, AlphaBlox and Oddpost should help drive this point home.

It describes the struggle it took to develop applications with rich user interfaces for web browsers, especially early versions of IE. Javascript was the programming language used.

Along the line browsers evolved (as well as the browser-language interface called the DOM), the language matured, and programming techniques were discovered.

So, yes, it is the language. But it is good to keep in mind that things are not always a simple as they may seem on first sight.

via Digital Mars C++

C++ [is] indisputably the most powerful programming language in the world. For reasons understood by many, it has, however, become a very complex language, and many a novice has followed after the siren song of lesser languages.

So is launched The C++ Source, the authoritative voice for the C++ community on the web. The board of editors is a veritable Who's Who of C++. Articles are peer-reviewed. There is not much content yet, but it looks like they offer live feeds. The journal's premiere article, "The Spirit of C," offers a potted history of C.

Like BCPL, B was a typeless language with a rich set of operations on machine words... How well does B embody The Spirit [of C]? Almost perfectly, in my opinion. "Trust the programmer" and "Don't prevent the programmer from doing what needs to be done" are obvious characteristics of a typeless language. [Meanwhile, however, the] C++ language is very nearly completely type-safe, which is a good thing, as its type system is arguably the most complex of any language.

Put that in your pipe and smoke it.

C-omega, Microsoft Research's experimental language featuring asynchronous concurrency (formerly, Polyphonic C#) and XML data types (Xen), is now available for download.

I think this is an interesting project. It was discussed here several times in the past.

I think that the integration of the new features with the core language is quite nice (e.g., XML types and the type system), so I suggest taking a look even if you are not particularly in favor of embedding XML in programming language.

The Cw home page includes links to relevant papers. And here's a LtU discussion of Xen and a discussion of Polyphonic C#.

The ongoing LtU discussion.

A very pleasant 1996 interview with Donald Knuth by Jack Woehr of Dr. Dobb's Journal.

(Link)

Here's something to exercise both brain hemispheres. Henk Barendregt needs no introduction for many LtU readers - he literally wrote "the book" on the lambda calculus, and that only hints at the profound impact his work has had on lambda calculus and type theory.

The page linked above lists two overlapping papers, both about reflection:

Reflection plays in several ways a fundamental role for our existence. Among other places the phenomenon occurs in life, in language, in computing and in mathematical reasoning. A fifth place in which reflection occurs is our spiritual development. In all of these cases the effects of reflection are powerful, even downright dramatic. We should be aware of these effects and use them in a responsible way.

A prototype situation where reflection occurs is in the so called lambda calculus. This is a formal theory that is capable of describing algorithms, logical and mathematical proofs, but also itself.

As the first paragraph quoted above implies, the scope of these two papers extends far beyond the lambda calculus, into fields such as biology and meditation. Between the two papers, there's something for everyone:

"Reflection and its use, from science to meditation" is wide-ranging, covering reflection related to living cells, formal languages, mathematics, art, computers, and the human mind.

"Reflection and its use, with an emphasis on languages and lambda calculus", focuses specifically on reflection in formal languages, including combinatory logic and lambda calculus.

Welcome to the new series alt.lang.jre. While most readers of this series are familiar with the Java language and how it runs on a cross-platform virtual machine (part of the JRE), fewer may know that the JRE can host languages besides the Java language. In its support for multiple languages (including some that pre-exist the Java platform) the JRE provides a comfortable entry point for developers coming to the Java platform from other backgrounds. It also gives developers who have rarely, if ever, strayed from the Java language the opportunity to explore the potential of other languages without sacrificing the familiarity of the home environment.

This series may become an amusing resource.

The first installment is about Jython.

This may be of interest to LtU readers.

Most of the specific language features were discussed here previously, but the C# perspective may make this worth a look.