Sam Carr’s Dog Speaks

I just installed JRuby on my Windoze XP box and thought I would share my experience for anyone interested in doing the same. It’s pretty straight forward, unless you know nothing of setting path variables in Windoze.

First, you’ve got to download JRuby (I got it from the jruby codehaus repository) and uncompress it into your choice of location. I grabbed the 1.1.2 binary tarball.

Next, you need to make sure you have a compatible Java runtime environment (JRE) or Java development kit (JDK) installed. If you don’t have one already, you can get these from the Sun Java site. You’ll notice the ‘Popular Downloads’ menu on the right has what you need. I already had this installed for my NetBeans installation.

Now comes the fun part. Make a note of the path to the JRE or JDK directory, as well as the path to your JRuby directory. I chose to install these as follows:

• JDK: D:\programs\Java\jdk1.6.0_06
• JRuby: D:\jruby-1.1.2

We’re nearly there! Next, just follow along:

1. Right click on “My Computer” and select ‘Properties’.
2. Choose the ‘Advanced’ tab at the top.
3. Click on the ‘Environment Variables’ button near the bottom.
4. Click the ‘New’ button under the ‘User variables’ section.
5. For ‘Variable name’, put JAVA_HOME and for Variable value, put the path to your java install directory. Click the ‘OK’ button.
6. Again, click on the ‘Environment Variables’ button near the bottom.
7. For Variable name, put JRUBY_HOME and for Environment variable, put the path to your JRuby install directory. Click the ‘OK’ button.
8. Select your PATH variable and click on the ‘Edit’ button.
9. If the ‘Variable value’ field is empty, put your JRuby install directory’s path followed by \bin (mine: D:\jruby-1.1.2\bin)
10. If the ‘Variable value’ field is not empty, put a semi-colon followed by your JRuby install directory’s path followed by \bin (mine: D:\jruby-1.1.2\bin)
11. Click on the ‘OK’ button then click on the ‘OK’ button then click on the ‘OK’ button to get out of all this mess.

Finally, open a command prompt, type ‘jruby -v’ and hit return!

I tried to be as verbose and explicit as I thought possibly necessary in these directions. If I missed something or messed something up, please post to let me know and I will change or add to it right away.

This is an explanation I gave to a student in class today of how the modulus operator behaves in Ruby. As I was writing the explanation down, it all became quite clear to me. I only had a tentative grasp on this concept until trying to explain it. That’s a good feeling when your helping another to understand something gives you clarity on the subject.

Given (-n % x) or (n % -x), the RHS (right hand side) of the modulus operation must be multiplied by the negative integer closest to 0 that will get it past the number on the LHS (left hand side). Then, the result is the difference between this number and the LHS. e.g.:

-7 % 3   # result is 2
# climbing (positive) from -9 (3 * -3) to -7

7 % -3   # result is -2
# dropping (negative) from 9 (-3 * -3) to 7

Of course, when the polarity is the same on both sides, such as (n % x) or (-n % -x), you just multiply the RHS times the positive integer that gets you the closest to the RHS without going past it then the result is the difference between the remainder and the LHS. e.g.:

7 % 3    # result is 1
# climbing (positive) from 6 (3 * 2) to 7

-7 % -3  # result is -1
# dropping (negative) from -6 (-3 * 2) to -7

It might help to note that in Ruby, the RHS always dictates the polarity of the result.

Over at Jeff Atwood’s blog on the Coding Horror site, there is quick mention of a foible at Mensa’s web site. The problem he alludes to, and which many comments point out and discuss at great length, is the lack of security used with the site’s login credentials.

What I find quite humorous is that the Mensa site’s ‘forgotten password’ page appears to be located within the calendar section of the site as an event. Mensa membership is supposedly based upon processing power and not memory, so why make a calendar event out of a member’s lack of memory? :-P

Happy Albert ‘Cerebronaut’ Hawking Brain Fart Day!!!

I finally got a syntax highlighter installed. I figure that since I’m taking the free Ruby course at RubyLearning.org, I should make my code look nice (and be more usable) when I decide to put some here on my blog. Just to get things rolling, here is a bit of code from one of the exercises I’ve done during the first few weeks of the course.

class Dog
  def initialize(name)
    @name = name.capitalize
    @what = self.class.to_s.downcase
    puts "Hi! I'm #{@name}, your new #{@what}!"
  end

  def teach(new_trick)
    @tricks = Array.new unless @tricks
    @tricks += [new_trick]
    puts "#{@name} now knows how to #{new_trick}!"
  end

  def show_tricks
    list_of_tricks = [@tricks[0]]
    1.upto(@tricks.length-1) do |modify|
      list_of_tricks += [" and #{@tricks[modify]}"]
    end
    @name + ' knows how to ' + list_of_tricks.to_s
  end

  def bark
  end

  def eat
  end

  def chase_cat
  end

  def to_s
    @name + " (your #{@what})"
  end

  def capable_of?(capability)
    self.respond_to?(capability) ?
    puts("I can #{capability} or my name's not #{@name}!") :
    @tricks.include?(capability) ?
    puts("I have recently been taught to #{capability}!") :
    puts("This is something I have not heard of before... \
    #{capability} you said?")
  end

  def method_missing(method, *more_arguments)
    "#{@name} cocks it's head to the side as if to say \n\t\
    \"I don't understand what #{method} means.\""
  end
end

# a few examples of usage:
rex = Dog.new 'rex'
max = Dog.new 'Max'
rex.teach 'jump through hoops'
ObjectSpace.each_object(Dog) {|dog| dog.teach('chase cars') }
puts rex.show_tricks
rex.capable_of? 'bark'
rex.capable_of? 'chase cars'
rex.capable_of? 'fetch'
puts "#{max} is feeling a bit left out..."

Sadly, I had misinterpreted the challenge guidelines. The instructor wanted the learned tricks to be methods and not properties. Anyhoot, this post is just so I can see what the highlighter will do on my blog. :-P

Just testing the posting capabilities of my cellular phone. Alright, so I’m just checking my ability to post with my phone. Semantics. heh.

Well, I signed up for a free online Ruby course at rubylearning.org some time last week. Classes start tomorrow and I’m pumped.

I’ve been seeing the popularity of Ruby, decidedly due to the Rails framework, skyrocket in the past few years. It seems that lately, you can hardly go to a web design or web development centric site without seeing a bright red gem or a red locomotive on the home page.

I read somewhere that Ruby is entirely Oo, which really piqued my interest. I’ve been wanting to get my noodle wrapped around OOP for years while dealing with PHP and javascript; not to mention (though I am) my very short lived foray into the seemingly mind-numbing world of C++ that I embarked upon.

Once I realized that Ruby might hold the key to my eternal salvation, I decided not to take my usual tack when trying to learn a programming or scripting language. That process would be best described as: buy a few $50 tomes, crack them open enough to get a feel for the writers’ personalities and then let them sit on my bookshelf while knowing that I am free at any time to pick them up and soak it all in.

I happened upon a digg post about The Pirate Bay being interviewed by the BBC and it made me sad to see so much ignorance-by-choice lumped into one small page.

If a musician crafts a song and decides to share it with the world through album sales, and the first person to buy a copy makes it available to the rest of the world for free, that is piracy. If another person cruising the internet finds the song and grabs a copy without having first purchased it, that is piracy. If a third party knowingly and willingly makes arrangements for this transaction to be made, that is also piracy. It doesn’t matter that the captain of the pirate ship didn’t board the other vessel, rape any women or even see the loot or know what it was; the captain is a pirate. Of course, you can throw Photoshop or Office or whatever “created for profit” blob of 1s and 0s you want to in place of the song and the idea is just as valid.

I have to give an example of the inherent mentality of even the guys that run The Pirate Bay. Peter Sunde, one of the four main pirates running the site, said this:

Nobody is crying that people who used to go around selling ice to people do not have a job anymore because of the fridge…

zomgwtfbbq?!?! Do you think there is the possibility that just maybe it’s because nobody is stealing ice? People are making it themselves with a tool that was made for that purpose. Nobody is saying you can’t use the computer to make your own movies, music, software, etc. Nobody will go around crying about the people you put out of business by making your own property.

I do understand there should be limits to what can be considered property. Inevitable progressions of data manipulation processes should not be patentable. This includes, but is not limited to, turning 1 into 0 by subtracting 1 from itself. It may seem absurd to even consider patenting this process, but sillier patents have been approved.

It’s not that I never join the ranks of the eye patch wearing online horde, I’m just tired of constantly hearing people use ‘freedom of data’ or ‘freedom of information’ as a mantra for the rationalization of theft. I do realize that laws governing property are never going to be ‘right’. I also believe real estate should not be property, but that is a discussion for another time. In fact, the only thing that any laws can actually do is try to impinge upon people’s freedom and sometimes succeed for good or bad. In many cases, laws are used for horrific travesties of justice; in most cases, they are a necessary evil put into place to actually protect freedom.

Don’t get me wrong, I am a true anarchist at heart even if not always in actions, as the flip side of that coin is death; absolute peace is only possible, though not assured, in death. It’s late. I’m tired. Too many tangents roaming in out of he fog… you get my drift. respect:good::piracy:bad (and I still think piracy is the wrong word to be used for this type of theft)

…as we know it. I’m not so sure I feel fine, though. I just saw ‘An Inconvenient Truth‘ a couple of days ago. It stars Al Gore (he used to be the next president of the US). It’s actually a documentary style flick following his campaign against global warming. The facts he presents in his presentation are easily followed and show a dismal future for anyone living through and beyond the next 10 to 20 years.

The correlation between atmospheric CO₂ and temperatures are somewhat (slight understatement?) disheartening. Through natural processes, the CO₂ in the atmosphere has gone up in the past to the same approximate levels as we are seeing now, with the atmospheric temperatures following suit. However, this time it is our polluting of the atmosphere (primarily due to our dependence on fossil fuels) and deforestation of the land that is causing this escalation of atmospheric CO₂. While the amount of fossil fuel being used by the population will have to fall in the near future, we don’t seem to have that much time before the projected increase in our atmospheric CO₂ causes the temperatures to rise to levels never seen before in the history of life on Earth.

Oddly, and somewhat confusingly to the layman (me), this will actually cause another ice age (along with other weather related catastrophes). This is due to the way that the oceanic currents keep the temperatures moderated in the gaseous atmosphere. It is proven that temperatures rising in the past (at the end of the last ice age) caused the glacial ice on the north american continent to melt and rush into the North Atlantic. The desalinization caused the temperature regulating oceanic currents to change, which, in turn, caused a continuation of the ice age.

I know the Mesoamerican people’s calendar ends on December 21^st 2012 on the Winter Solstice. Maybe this destruction of the atmosphere, and thus our ability to survive in it, is the reason. I have heard other theories as to why their calendar ends at this time (alien contact, comet impact, etc.), but this seems to be a highly plausible explanation. Of course, ‘explanation’ doesn’t really work here, as there is so much that is currently unexplainable about future predictions by ourselves and our predecessors. I suppose only time will tell. While your waiting for this time to pass, I highly suggest that you go see ‘An Inconvenient Truth’ at a theater near you as soon as you get a chance. It just might change the way you live.