Category Archives: Programming

cl-test-grid

Posted on 2012-05-08 by jcs

Vladimir Sedach has a post up that describes the cl-test-grid project. The idea is that Quicklisp users download the cl-test-grid, tell it what CL implementations are available, and run the test. It runs tests against many of the libraries in … Continue reading →

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Scheme and Common Lisp

Posted on 2012-05-07 by jcs

I’ve been using Scheme and Common Lisp almost exclusively for over 10 years. During that time, I tended to favor Scheme because I liked its clean design and simplicity, the named let, continuations, and the simplicity that being a Lisp-1 … Continue reading →

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Using Quicklisp

Posted on 2012-05-06 by jcs

Back in March I wrote that I had loaded and starting using Zach Beane’s Quicklisp. Since then I have used it with several small projects and I really like it. It does two things for me: Makes it super easy … Continue reading →

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Solution to the Two Challenges

Posted on 2012-05-04 by jcs

The other day, I presented two Elisp coding challenges. I specified Elisp because Irreal readers tend to like Emacs related posts. The down side of that is that several of you worried about bignums and other Emacs limitations. That wasn’t … Continue reading →

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Playing with Common Lisp’s Compiler Macros

Posted on 2012-05-03 by jcs

Back in April, Robert Smith of Symbo1ics Ideas wrote an excellent post on solving the m-of-n Boolean Circuit problem. The problem is nominally about building a boolean circuit having n inputs that returns TRUE if at least m of the … Continue reading →

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Two Elisp Challenges

Posted on 2012-05-02 by jcs

I ran across a couple of nice interview questions and an interesting story over at Tanya Khovanova’s Math Blog. The two questions are: Given a list of integers from 1 to n but with one of the integers missing, write … Continue reading →

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DOCUMENTATION-TEMPLATE

Posted on 2012-05-01 by jcs

I’m just starting a Lisp project that, among other things, involves fiddling with dates. Working with dates isn’t particularly hard but it’s also not very rewarding. Oddly, Common Lisp doesn’t have any functions to format and manipulate dates. I certainly … Continue reading →

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Checking The Easy Cases First

Posted on 2012-04-30 by jcs

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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TPK In Common Lisp

Posted on 2012-04-28 by jcs

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

Posted on 2012-04-27 by jcs

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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