Implicit Phasing for R6RS Libraries
Abdulaziz Ghuloum and R. Kent Dybvig, Implicit Phasing for R6RS Libraries, Proc. ICFP 2007. The forthcoming Revised Report on Scheme differs from previous reports in that the language it describes is structured as a set of libraries. It also provides a syntax for defining new portable libraries. The same library may export both procedure and hygienic macro definitions, which allows procedures and syntax to be freely intermixed, hidden, and exported. This paper describes the design and implementation of a portable version of R6RS libraries that expands libraries into a core language compa

Scratch: Programming for All
Mitchel Resnick, John Maloney, Andrés Monroy Hernández, Natalie Rusk, Evelyn Eastmond, Karen Brennan, Amon Millner, Eric Rosenbaum, Jay Silver, Brian Silverman, Yasmin Kafai, Scratch: Programming for All, Communications of the ACM, vol. 52, no. 11, November 2009. When Moshe Vardi, Editor-in-Chief of CACM, invited us to submit an article about Scratch, he shared the story of how he learned about Scratch: A couple of days ago, a colleague of mine (CS faculty) told me how she tried to get her 10-year-old daughter interested in programming, and the only thi

Bytecodes meet Combinators: invokedynamic on the JVM
Bytecodes meet Combinators: invokedynamic on the JVM. John Rose. VMIL'09. The Java Virtual Machine (JVM) has been widely adopted in part because of its classfile format, which is portable, compact, modular, verifiable, and reasonably easy to work with. However, it was designed for just one language—Java—and so when it is used to express programs in other source languages, there are often “pain points” which retard both development and execution. The most salient pain points show up at a familiar place, the method call site. To generalize method calls on the JVM, the JSR 292 Expert

Go or Unladen Swallow?
Go is a new programming language to come out of google and this thread on Google discouraging python internally for new projects seems more than just coincidence. Go is an attempt to combine the ease of programming of an interpreted, dynamically typed language with the efficiency and safety of a statically typed, compiled language. By combining dynamic features, safety, garbage collection and efficiency in a single language and environment, Go claims to remove the reasons why programmers end up building systems u

Scheduled downtime
LtU will be taken offline for some time tomorrow (Tuesday 9th) due to a data center move. The downtime could range from a few minutes to a few hours. The exact time this will occur is unknown, but you'll be able to tell because LtU will be unreachable. :-)