I also blog from time to time at CTC Cambridge, Listen With Others, and Otterly. I re-post everything at garethrees.org, so if you want to read all my posts, you should be following my RSS feed.

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When I had interviewed for the job, the interviewer had explained that I was needed to work on their JavaScript engine. The company was a web development tools startup, and they had spotted that it would be a good idea to have JavaScript code running on the server as well as on the client, so that you could share your business logic and validation ( Read more... )

The story so far: I wrote a solver for a generic exact cover problem in Python, and used it to find polyomino tilings. The reason for using Python was because Python’s simplicity, terseness, and flexibility makes it easy to write solvers for other combinatorial problems. ( So let’s have a look at a second problem … )

Karp (1972) introduces the name ‘exact cover’ for the following decision problem:
INPUT: Family Sj of subsets of a set ui, i=1,2,…,t

PROPERTY: There is a subfamily Th ⊆ Sj such that the sets Th are disjoint and ∪Th = ∪Sj = ui, i=1,2,…,t

(The problem being to determine, for an arbitrary input, whether it possesses the property.) Karp goes on to ( Read more... )

So, another day at the customer site, another issue to fix:
Issue 234. Over the past three months, the performance of [PRODUCT] has regressed. In December, at commit 919074d, [TESTCASE] ran in 21 seconds, but now it takes 44 seconds.

The first step is to check that the problem is reproducible (it is), ( and the next is to run a git bisect to see ( Read more... )

I’ve been maintaining the Perforce/Emacs integration for a couple of years now, so it’s time for a retrospective. … Perforce and Emacs are tools that I use all day every day, which means that small inconveniences in the integration stand out to me and I can see clearly cases where I have a frequently performed task that deserves some extra ( Read more... )

It was Friday afternoon at the customer site and I had completed my tasks for the week. I had implemented the new feature and its test cases, written a design justifying the implementation, and drafted a section of the user manual explaining how to use it, so now I was looking for something else to do. In any large program, there are always things ( Read more... )

Joe sits in the office of his detective agency in Vientiane, drinking and smoking, watching the rain come down, and reading trashy fiction:
The book was a worn paperback with a garish, colourful cover. It showed a multi-story building in the final stages of collapse, a dusty African street, and people running away from the blast. The book was ( Read more... )

Jean le Flambeur, gentleman thief, is sprung from prison by the beautiful Mieli, who persuades him to undertake one last job. Author Hannu Rajaniemi works hard to obscure the familiar outline of this hoariest of heist plots, by layering on the worldbling with a trowel: The hidden Sobornost tech beneath the Oortian sapphire coral wakes up. The ( Read more... )

In ‘Completion annotations’, I illustrated the interactive completion feature in Emacs with a screenshot showing what happens if you type M-x set-cursor-color RET Dark TAB: you get a *Completions* buffer containing the colour names starting with ‘Dark’. Nick Barnes posted a comment pointing out a potential usability improvement: It would be nice ( Read more... )