Other articles

1. [LaTeX] Typesetting Premise and Conclusion Form Arguments

   This is the easiest way I have found to typeset premise and conclusion style arguments in LaTeX. First, add this to your preamble:

   \usepackage{amssymb}
   

   Then use something like this to typeset the argument:

   \begin{itemize}
       \item[1.] Premise One.
       \item[2.] Premise Two.
       \item[3.] Premise Three.
       \item[$\therefore ...

   read more

2. [Ruby] Genetic String Evolver

   Inspired by Richard Dawkins' weasel program, this is a genetic algorithm, written in Ruby, to evolve the same "METHINKS IT IS LIKE A WEASEL" string. It's really fun to experiment with changing the probability constants (mutation, reproduction) and the algorithm in Evolver#advance, which advances the population of strings ...

   read more

3. Factorization Correlation Experimentation Tool

   Here's a Ruby script to experiment with correlations that may be useful in developing a genetic (evolutionary) algorithm for factoring the product of two primes. The comments explain it:

   #!/usr/bin/env ruby
   # Let C = F1 * F2, where F1 and F2 are primes.
   #
   # This script gives a visual aid ...

   read more

4. Vim: Make Rainbow Parentheses Work in PHP

   EDIT: What I propose here doesn't actually fix it, it still fails when there's a greater-than sign inside an if statement. I have spent over 8 hours trying to get this to work and that is too much, so I am giving up. If you find a solution ...

   read more

5. Why Unsafe State != Deadlock

   You have a list of processes and a list of resources, and for each process you have:

   • The number of each resource they will ever need at once.
   • The number of each resource they are currently allocated.

   When a process makes a request for a resource, you only allocate the ...

   read more

6. x86 Stack Diagrams

   All of the x86 stack diagrams I could find are either cluttered with too much information, can't be read from a distance, or put the high address on top (I'm sure there are people who prefer that but... I'm not one of them). So I made my ...

   read more

7. Visual Basic's "With" in Ruby

   def with( obj )
     yield obj
   end
   
   with Math do |m|
     puts m.exp( 1 )
     puts m.exp( 2 )
     puts m.exp( 3 )
   end
   
   # Deeply nested modules
   module Foo
     module Bar
   
       module Baz
         A_CONSTANT = 3
         def self.aMethod( x )
           x * A_CONSTANT + A_CONSTANT
         end
       end
   
       module Biz
         def self.anotherMethod( x )
           "hello ...

   read more

8. Ruby Obfuscation

   Just having fun...

   Obfuscated #1

   This evaluates to the string "?".

   ??????????????:????????:??:??:??:??:?????:?? # => "?"
   

   Obfuscated #2

   $i=0;[$c="[$s=['p '],[$s<<[*1?3??'+?<+?3:?y:?]],$s+=[?b],$s|=[*?y+?'],$s[2,0]=5??r+?u:?$],($i+=1)<30?eval($s.join<<?;<<$c):nil]",eval($c)]
   

   Output

   "<3ruby"
   "<3ruby"
   "<3ruby"
   "<3ruby"
   "<3ruby"
   "<3ruby"
   "<3ruby ...

   read more

9. Ruby Maze Solver

   Here's a recursive-backtracking ASCII maze solver I wrote to practice ruby. The o's are the solution.

   Output

   $ ruby maze.rb maze.txt
   ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
   ++++oooooooo  ++++++++++++++++++++++ ++++++++++++++++++++++++        ++++ ++++++
   +oooo++ +++o++++++++++++++++++++++++ ++++ +++++++++++++++++++ +++ +++++++ ++++++
   ++++ ++   oo+++++++++++++++++++ ++++ ++++                 +++ +++ +++++++ ++++++
   ++++ ++ ++o++++++++ooooooo+++++ ++++ ++++ +++++++++++++++++++ +++         ++++++
   ++   +++++o++++++++o+++++o+++++           ++++ ++++++++++++++ ++++++++ +++++++++
   ++++++++++o++++++++o+++++o+++++ +++++ ++++++++ +++oooooooooooooo++++++ +++++++++
   ++++++++++o+oooooooo+++++ooooooo+++++ ++++++++ +++o++++++++ +++o++++++ +++++++++
   ++++++++++ooo++++++++++++ +++++o+++++ +++++++++   o++++++++++++o++++++ +++++++++
   +++++++++++++++++++++++++      o++++++++++++++++++o      ++++++o       +++++++++
   +++++++ +++++++++++++++++++++++o ...

   read more

10. My Favorite 'Rubyisms'

    I've been using Ruby at work to write watir tests, and I am constantly amazed at how elegant it is. Here are some of my favorite techniques:

    Pass a default value block to Hash.new to implement a memoized recursive function:

    fibonacci = Hash.new do |h,k|
        h[k ...

    read more

11. Random .vimrc Tips

    Here are some of my favorite .vimrc lines.

    Save quickly from any mode by pressing CTRL+:

    imap <C-\> <Esc>:w<Cr>
    map <C-\> <Esc>:w<Cr>
    

    Make indenting and de-indenting in visual mode preserve the selection:

    vnoremap > ><CR>gv
    vnoremap < <<CR>gv
    

    Quick case insensitive search with double slash or ...

    read more