Building Correct Software

An Introduction to Contracts
There are two measures of the quality of software: how correct it is, and how robust it is.
This article is about using Contracts to improve the correctness of software, with the aim of getting it right the first time round.
An implementation’s correctness can only be judged according to its specification. If [...]

Building PLT-Scheme on Ubuntu (Intrepid Ibex)

I had reason to build PLT-Scheme 4.1.5 the other day on an Ubuntu system (Intrepid Ibex) (OK, I was trying to get a build of Fluxus up and running).
It was almost entirely straightforward, except for not knowing ahead of time which development packages were needed for the build to complete successfully. As I had [...]

Scheme REPLs and readline (or lack thereof)

Most Scheme implementations provide a command-line REPL, allowing you to interactively enter commands and play about with the language. Unfortunately, they can be incredibly frustrating to use out-of-the-box, all because Scheme distributions tend ship without readline support. As far as I can tell, this is down to licensing issues.
readline is what provides the [...]