I've finally gotten around to uploading my custom Mac OS X keyboard layout. The most significant additions over the standard U.S. keyboard layout are: mathematical symbols (relevant to calculus and symbolic logic), Greek characters, and arrows. It also makes (, ), :, and | unshifted.

Disambiguation (disambiguation).

(via Making Light)

One bit of advice sometimes given to the novice programmer is don't ever compare floating-point numbers for equality, the reason being that floating-point calculations are inexact, and one should use a small epsilon, allowable error, instead, e.g. if (abs(value - 1.0) < 0.0001).

This advice is actually wrong, or rather, overly strong. There is a ( Read more... )

( Read more... )

There seems to be a recurring misconception about writing .asd files. It is not necessary to start your asd with (defpackage :foo.system ...) (in-package :foo.system) to “avoid polluting the package asdf loads your system in”.

Every time an .asd file is loaded, ASDF creates a fresh package to load it in. The relevant code from ASDF is:

(defun ( Read more... )

I've been having a lot of thoughts lately I'd like to publish, but seem a little bit too short for A Blog Post. Some options

1. Considered signing up for Twitter. Pro: short stuff is expected there; participating in the hot new thing; people interested in short-form will be on twitter and using the follow feature. Con: Reliability problems; YA thing ( Read more... )

Rosetta Code is a wiki where a variety of programming problems and language features are demonstrated in many languages, allowing language learning and comparison of features and paradigms.

If you'd like to contribute Common Lisp code to the project, I've just completed a classification of tasks in CL (like my prior one for E), so that it's easy ( Read more... )

Common Lisp provides compile-file whose purposes is to convert a CL source file into an (implementation-defined) format which usually has precompiled code and is designed for faster loading into a lisp system.

compile-file takes the pathname of a textual lisp source file. But what if you want to compile some Lisp code that's not in a file ( Read more... )

Apple's Sampler is a profiler based on the principle of periodically collecting the entire call stack of the executing threads, then summarizing these stacks to show what occurs frequently; primarily, as a tree, rooted at the bottom of the stack, where each node shows the number of times that call sequence was found on the stack.
SBCL's sb-sprof ( Read more... )

I recently found I wanted to retrieve some old Apple IIgs image files. After vague memories and some research, I found that they were “Super Hi-Res” images, which are dumps of screen memory in SHR mode, passed through the PackBytes compression routine.

I haven't found any on-the-web documentation of the SHR layout, but according to books and my ( Read more... )