Monthly Archives: April 2012

Checking The Easy Cases First

Over the weekend, I was amusing myself with this problem from the always entertaining Programming Praxis. The problem is to partition the set {1, 2, ..., 16} into two equally sized subsets such that The sums of the integers in … Continue reading

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Troubleshooting Emacs Libraries

While trawling around the WikEmacs site today, I came across this page on troubleshooting that explained some commands that I wasn't familiar with. The first two are helpful if you are trying to search out library problems. For example, if … Continue reading

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TPK In Common Lisp

Yesterday I wrote about the Trabb Pardo Knuth algorithm and gave an implementation in Emacs Lisp. Elisp allows an nice implementation but was a bit frustrating because the Elisp interpreter handles overflows internally and never signals an overflow condition. Therefore, … Continue reading

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The Trabb Pardo Knuth Algorithm in Elisp

The latest Programming Praxis Exercise is interesting. Back in 1973, Luis Trabb Pardo and Don Knuth published an algorithm that was meant to assess the power of a programming language. The algorithm was Ask for 11 numbers to be read … Continue reading

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The WikEmacs Elisp Cookbook

I stopped by WikEmacs today to see how the site was progressing. It looks pretty nice and has obviously seen some hard work by its contributors. Being me, I immediately went to the Emacs Lisp Cookbook to see how it … Continue reading

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And So It Begins

Tor/Forge, part of the Macmillan empire announced that they will start shipping their ebooks without DRM starting in July. This is the beginning of the DRM death spiral predicted by Charlie Stross (although he has tempered that prediction a bit … Continue reading

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Decimalizing Latitude and Longitude

Xah Lee has reintroduced a challenge from last year. Given a string of latitude/longitude is degrees, minutes, seconds, write a function that returns them as signed decimal numbers. That is, "37°26′36.42″N 06°15′14.28″W" → (37.44345 -6.253966666666667) I remember looking at this … Continue reading

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A Key Sequence For revert-buffer

The other day I was trawling through Aaron Hawley's excellent Emacs Reference Sheet and came across the entry for【Ctrl+x Ctrl+v Return】saying “same as previous.” The previous entry was for revert-buffer. My first thought was “How did I not know this?” … Continue reading

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Let Over Lambda

Last year, I reported that most of the book Let Over Lambda was posted on the Internet. I recommended that anyone interested in Lisp take a look at it. I still make that recommendation but be warned: you will end … Continue reading

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The Emacs clean-buffer-list Command

Some time ago, I enabled save-desktop-mode in Emacs and I've been really happy with it. I generally never close Emacs but sometimes I need to restart it for one reason or another or an OS upgrade requires me to reboot. … Continue reading

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