Category: Link

Whalesong: a Racket to JavaScript compiler

Whalesong is a compiler from Racket to JavaScript; it takes Racket programs and translates them so that they can run stand-alone on a user’s web browser. It should allow Racket programs to run with (hopefully!) little modification, and provide access through the foreign-function interface to native JavaScript APIs. The included runtime library supports the numeric tower, an image library, and a framework to program the web in functional event-driven style.

Destructuring Lists Using CA*D*R vs First, Second, … vs Pattern Matching

This thread discusses the pros and cons of using the CA*D*R functions vs named first, second, third, list-tail, … and so on vs pattern matching for the same task.
I thought that pattern-matching was the best way to do it; and now I’m curious about why CA*D*R is better.

Pandoc A Universal File Markup Language Converter

If you need to convert files from one markup format into another, pandoc is your swiss-army knife. Need to generate a man page from a markdown file? No problem. LaTeX to Docbook? Sure. HTML to MediaWiki? Yes, that too. Pandoc can read markdown and (subsets of) reStructuredText, textile, HTML, and LaTeX, and it can write plain text, markdown, reStructuredText, HTML, LaTeX, ConTeXt, PDF, RTF, DocBook XML, OpenDocument XML, ODT, GNU Texinfo, MediaWiki markup, textile, groff man pages, Emacs org-mode, EPUB ebooks, and S5 and Slidy HTML slide shows. PDF output (via LaTeX) is also supported with the included markdown2pdf wrapper script.

Pandoc understands a number of useful markdown syntax extensions, including document metadata (title, author, date); footnotes; tables; definition lists; superscript and subscript; strikeout; enhanced ordered lists (start number and numbering style are significant); delimited code blocks; markdown inside HTML blocks; and TeX math. Other options include “smart” punctuation, syntax highlighting, automatically generated tables of contents, and automatically generated citations (using citeproc-hs). If strict markdown compatibility is desired, all of these extensions can be turned off with a command-line flag.

(via pandoc)

SchemaSpy: A Graphical Database Schema Metadata Browser

SchemaSpy is a Java-based tool that analyzes the metadata of a schema in a database and generates a visual representation of it in a browser-displayable format. It lets you click through the hierarchy of database tables via child and parent table relationships as represented by both HTML links and entity-relationship diagrams. It’s also designed to help resolve the obtuse errors that a database sometimes gives related to failures due to constraints.

This is an excellent tool in its own right; and if nothing else for its beautiful use of Graphviz.
See the example(s) here.

Penetrating Oil Review

Machinist’s Workshop magazine actually tested penetrants for break out torque on rusted nuts.
Significant results! They are below, as forwarded by an ex-student and professional machinist, Bud Baker.
Don’t forget the April 2007 “Machinist’s Workshop” magazine comparison test.
They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a “scientifically rusted” environment.

  • Penetrating oil ….. Average load
  • None …………………. 516 pounds
  • WD-40 ……………….. 238 pounds
  • PB Blaster ………….. 214 pounds
  • Liquid Wrench …….. 127 pounds
  • Kano Kroil …………… 106 pounds
  • ATF-Acetone mix…….53 pounds

The ATF-Acetone mix was a “home brew” mix of 50 – 50 automatic transmission fluid and acetone.
Note the “home brew” was better than any commercial product in this one particular test.
Our local machinist group mixed up a batch and we all now use it with equally good results.
Note also that “Liquid Wrench” is about as good as “Kroil” for about 20% of the price.
(via Concours Tech)

GSL Shell

GSL Shell is an interactive interface that gives access to the GSL numerical routines by using Lua, an easy to learn and powerful programming language. With GSL Shell you can access very easily the functions provided by the GSL library without the need of writing and compile a stand-alone C application. In addition the power and expressivity of the Lua language make easy to develop and tests complex procedures to treat your data and use effectively the GSL routines. You will be also able to create plot in real-time by using the powerful builtin graphical module.
GSL Shell is still a young project and it is currently not widely used. It still lacks some important features but we believe that it is very promising because it is built on top of three outstanding free software libraries: the GSL library, Lua and the AGG library. By using and combining together these software components GSL Shell gives the opportunity of doing advanced numerical calculations and produce beautiful plot of the data or mathematical functions.

(via GSL via Mike K.)
Like Mike said, looks like a nice complement to Octave or MATLAB.