the arc of software bends towards understanding
ghc --make is a useful mode in GHC which automatically determines what modules need to be compiled and compiles them for you. Not only is it a convenient way of building Haskell projects, its single-threaded performance is good too, by reusing the work of reading and deserializing external interface files. However, the are a number […]
The essence of stateless user interface is that actions you take with a program should not depend on implicit state. Stateless interfaces are easier to understand, because an invocation of a command with some arguments will always do the same thing, whereas in a stateful interface, the command may do some different than it did […]
You might be wondering: with the beta release of no-reinstall Cabal, is this functionality be coming to GHC 8.0? (Or even a new release of Cabal, since the no-reinstall feature works with GHC 7.10). Unfortunately, there is a split among the Cabal developers over whether or not the actual no-reinstall behavior should go into Cabal […]
Over this summer, Vishal Agrawal has been working on a GSoC project to move Cabal to more Nix-like package management system. More simply, he is working to make it so that you'll never get one of these errors from cabal-install again: Resolving dependencies... In order, the following would be installed: directory-1.2.1.0 (reinstall) changes: time-1.4.2 -> […]
My usual laptop setup is I have a wide monitor, and then I use my laptop screen as a secondary monitor. For a long time, I had two XMonad layouts: one full screen layout for my laptop monitor (I use big fonts to go easy on the eyes) and a two-column layout when I'm on […]
This year at ICFP, we had some blockbuster attendance to the Haskell Implementor's Workshop (at times, it was standing room only). I had the pleasure of presenting the work I had done over the summer on Backpack. You can grab the slides or view the presentation itself (thank you ICFP organizers for being incredibly on-the-ball […]
One of the major open problems for building a module system in Haskell is the treatment of type classes, which I have discussed previously on this blog. I've noted how the current mode of use in type classes in Haskell assume “global uniqueness”, which is inherently anti-modular; breaking this assumption risks violating the encapsulation of […]
Update. Want to know more about Backpack? Read the specification So perhaps you've bought into modules and modularity and want to get to using Backpack straightaway. How can you do it? In this blog post, I want to give a tutorial-style taste of how to program Cabal in the Backpack style. These examples are executable, […]
This summer, I've been working at Microsoft Research implementing Backpack, a module system for Haskell. Interestingly, Backpack is not really a single monolothic feature, but, rather, an agglomeration of small, infrastructural changes which combine together in an interesting way. In this series of blog posts, I want to talk about what these individual features are, […]
Today, I'd like to talk about some of the core design principles behind type classes, a wildly successful feature in Haskell. The discussion here is closely motivated by the work we are doing at MSRC to support type classes in Backpack. While I was doing background reading, I was flummoxed to discover widespread misuse of […]