Lambda the Ultimate

The popular Glasgow Haskell Compiler extends the Haskell 98 type system with several powerful features, leading to an expressive language of type terms. In contrast, constraints over types have received much less attention, creating an imbalance in the expressivity of the type system.

In this paper, we rectify the imbalance, transferring familiar type-level constructs, synonyms and families, to the language of constraints, providing a symmetrical set of features at the type-level and constraint-level. We introduce constraint synonyms and constraint families, and illustrate their increased expressivity for improving the utility of polymorphic EDSLs in Haskell.

1974 talk show style interview with the original developers of APL; complete with plaid jackets and a smoking host.

The Origins of APL Video

I've never used APL but I found the talk to be very interesting. They talk about how APL come about, its evolution and the character set. Worth watching.

Since other posters at LtU have taken an interest in the Fortress programming language in the past, I thought I'd mention that the Fortress team at Sun Labs has started a blog, to post a series of announcements and news items about Fortress. Our goal is to let people know about ongoing technical discussions and decisions, as well as the current status of the implementation. We will also post interesting examples of Fortress code. We hope to put up new posts at least weekly.

So far we have four posts. The first and fourth posts discuss the new wiki markup for tables and images for use in Fortress comments; the second post discusses some changes to the typing rules for conditional expressions that will help them to interact better with coercion. The third post is Jan-Willem Maessen's report on a pure (functional) implementation of the "treap" data structure in Fortress, and the fact that the nascent Fortress compiler can now compile it. Visit

http://projectfortress.sun.com/Projects/Community/blog

or click on the "Blog" item at the right-hand end of the menu bar on the main Wiki page.