Category Archives: Programming

My Solution to the Last Elisp Challenge

Posted on 2013-06-21 by jcs

The challenge was to convert the output from dstat so that all the bytes values (some of which are given as kilobytes or megabytes) to just bytes. Thus, 2k would become 2048 and 3M would become 3145728. Similarly, dstat outputs … Continue reading →

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Regular Expressions and Emacs Lisp

Posted on 2013-06-17 by jcs

Over at What keramida said…, Giorgos Keramidas poses an interesting problem. Given the following output from dstat, get rid of the B, k, and M suffixes by converting them into bytes. —-system—- —-total-cpu-usage—- –net/eth0- -dsk/total- sda- time |usr sys idl … Continue reading →

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Quickdocs Documentation

Posted on 2013-06-14 by jcs

Quickdocs keeps getting better and better. Now they have nicely formatted documentation for the Quicklisp packages. These are nice enough and easy enough to access that I use them for my primary package documentation. They’re a lot easier to bring … Continue reading →

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Lisp Web Tales

Posted on 2013-06-12 by jcs

Pavel Penev is writing a book, Lisp Web Tales, about Web applications and Common Lisp. He describes it as a set of tutorials and examples. I’ve been meaning to write about this for some time because it seems like a … Continue reading →

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SBCL 1.1.8 Is Out

Posted on 2013-06-06 by jcs

I just updated my Common Lisp system, SBCL, to the latest version, 1.1.8. Between now and the last update, I had upgraded OS X to Mountain Lion. That, of course, meant that I had to reload GCC and the other … Continue reading →

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Tail Call Optimization in Elisp

Posted on 2013-06-04 by jcs

If you’ve got a Lisp background—especially a Scheme background—you may have internalized recursion as a looping mechanism and general programming strategy. That doesn’t work with Elisp, of course, because each recursive invocation allocates a stack frame. Not to worry, though, … Continue reading →

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The Emacs defadvice Macro

Posted on 2013-05-27 by jcs

Evgkeni Sampelnikof has posted a nice introduction to defadvice. Emacs is all about having it your way and making it easy to do so. Very often it’s convenient to change the behavior of a built in command and since Emacs … Continue reading →

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DSLs

Posted on 2013-05-25 by jcs

I have a long standing love affair with Domain Specific Languages (DSLs). Back when I was writing in C, I wrote several compilers and associated interpreters for various DSLs. This mainly involved using fairly heavyweight tools like lex and yacc … Continue reading →

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The Coding Standard From Hell

Posted on 2013-05-19 by jcs

You say you hate your organization’s coding standards? You say they make the code harder to understand and maintain? You say they could only have been devised by a particularly moronic version of the pointy haired boss? Stop your whining … Continue reading →

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Emacs Hash Tables

Posted on 2013-05-15 by jcs

One of the most useful data structures in Computer Science is the hash table. I’ve been using them for my entire career and have implemented close to a hundred instances in several languages. That’s not as necessary these days as … Continue reading →

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