1. Opening This Book

Pretend that you’ve opened this book (although you probably have opened this book), just to find a huge onion right in the middle crease of the book. (The manufacturer of the book has included the onion at my request.)

So you’re like, “Wow, this book comes with an onion!” (Even if you don’t particularly like onions, I’m sure you can appreciate the logistics of shipping any sort of produce discreetly inside of an alleged programming manual.)

Then you ask yourself, “Wait a minute. I thought this was a book on Ruby, the incredible new programming language from Japan. And although I can appreciate the logistics of shipping any sort of produce discreetly inside of an alleged programming manual: Why an onion? What am I supposed to do with it?”

No. Please don’t puzzle over it. You don’t need to do anything with the onion. Set the onion aside and let it do something with you.

I’ll be straight with you. I want you to cry. To weep. To whimper sweetly. This book is a poignant guide to Ruby. That means code so beautiful that tears are shed. That means gallant tales and somber truths that have you waking up the next morning in the arms of this book. Hugging it tightly to you all the day long. If necessary, fashion a makeshift hip holster for Why’s (Poignant) Guide to Ruby, so you can always have this book’s tender companionship.

You really must sob once. Or at least sniffle. And if not, then the onion will make it all happen for you.

2. The Dog Story

So try this first bit of poignancy on for size:

One day I was walking down one of those busy roads covered with car dealerships (this was shortly after my wedding was called off) and I found an orphaned dog on the road. A wooly, black dog with greenish red eyes. I was kind of feeling like an orphan myself, so I took a couple balloons that were tied to a pole at the dealership and I relocated them to the dog’s collar. Then, I decided he would be my dog. I named him Bigelow.

We set off to get some Milkbones for Bigelow and, afterwards, head over to my place, where we could sit in recliners and listen to Gorky’s Zygotic Mynci. Oh, and we’d also need to stop by a thrift store and get Bigelow his own recliner.

But Bigelow hadn’t accepted me as his master. So five minutes later, the stupid dog took a different crosswalk than I did and I never caught up. So whereas he had previously only been lost once, he was now lost twice. I slowed my pace towards the life of Milkbones and an extra recliner. I had a dog for five minutes.

Stupid Benedict Arnold of a dog. I sat on a city bench and threw pinecones at a statue of three sheep crossing a bridge. After that, I wept for hours. The tears just came. Now there’s a little something poignant to get you started.

I wonder where he went with all those balloons. That crazy dog must have looked like a party with legs.

It wasn’t much later that I pulled my own Bigelow. I printed out a bunch of pages on Ruby. Articles found around the Web. I scanned through them on a train ride home one day. I flipped through them for five minutes and then gave up. Not impressed.

I sat, staring out the window at the world, a life-sized blender mixing graffiti and iron smelts before my eyes. This world’s too big for such a a little language, I thought. Poor little thing doesn’t stand a chance. Doesn’t have legs to stand on. Doesn’t have arms to swim.

And yet, there I was. One little man on a flimsy little train (and I even still had a baby tooth to lose at the time) out of billions of people living on a floating blue rock. How can I knock Ruby? Who’s to say that I’m not going to happen to choke on my cell phone and die later that evening. Why’s dead, Ruby lives on.

The gravestone:

What’s in his trachea? Oh, look, a Nokia!

Just my luck. Finally get to have a good, long sleep underground, only to be constantly disturbed by Pachelbel’s Canon going off in my stomach.

3. The Red Sun Rises

So, now you’re wondering why I changed my mind about Ruby. The quick answer is: we clicked.

Like when you meet Somebody in college and they look like somebody who used to hit you in the face with paintbrushes when you were a kid. And so, impulsively, you conclude that this new Somebody is likely a non-friend. You wince at their hair. You hang up phones loudly during crucial moments in their anecdotes. You use your pogo stick right there where they are trying to walk!

Six months later, somehow, you and Somebody are sitting at a fountain having a perfectly good chat. Their face doesn’t look so much like that childhood nemesis. You’ve met the Good Twin. You clicked.

So whereas I should probably be pounding your teeth in with hype about Ruby and the tightly-knit cadre of pertinent ancronyms that accompany it everywhere (whetting the collective whistles of your bosses and their bosses’ bosses), instead I will just let you coast. I’ll let you freefall through some code, interjecting occassionally with my own heartfelt experiences. It’ll be quite easy, quite natural.

I should offer you some sort of motivation, though. So, Smotchkkiss, I’m going to give my three best reasons to learn Ruby and be done with it.

1. Brain health.

   Vitamin R. Goes straight to the head. Ruby will teach you to express your ideas through a computer. You will be writing stories for a machine.

   Creative skills, people. Deduction. Reason. Nodding intelligently. The language will become a tool for you to better connect your mind to the world. I’ve noticed that many experienced users of Ruby seem to be clear thinkers and objective. (In contrast to: heavily biased and coarse.)

2. One man on one island.

   Ruby was born in Japan. Which is freaky. Japan is not known for its software. And since programming languages are largely written in English, who would suspect a language to come from Japan?

   And yet, here we have Ruby. Against the odds, Yukihiro Matsumoto created Ruby on February 24, 1993. For the past ten years, he has steadily brought Ruby to a global audience. It’s triumphant and noble and all that. Support diversity. Help us tilt the earth just a bit.

3. Free.

   Using Ruby costs nothing. The code to Ruby itself is open for all of the world to inhale/exhale. Heck, this book is free. It’s all part of a great, big giveaway that should have some big hitch to it.

   You’d think we’d make you buy vacuums or timeshare or fake Monets. You’d think there’d be a 90 minute presentation where the owner of the company comes out at the end and knuckles you into sealing the deal.

   Nope, free.

With that, it’s time for the book to begin. You can now get out your highlighter and start dragging it along each captivating word from this sentence on. I think I have enough hairspray and funny money on my person to keep me sustained until the final page.

4. How Books Start

Now, if you ever have read a book, you know that no book can properly start without an exorbitant amount of synergy. Yes, synergy. Maybe you didn’t know this. Synergy means that you and I are supposed to cooperate to make this a great reading experience.

We start off the book by getting along well in the Introduction. This togetherness, this synergy, propels us through the book, with me guiding you on your way. You give me a reassuring nod or snicker to indicate your progress.

I’m Peter Pan holding your hand. Come on, Wendy! Second star to the right and on till morning.

One problem here. I don’t get along well with people. I don’t hold hands very well.

Any of my staff will tell you. At the Opening Ceremonies of This Book (a catered event with stadium seating), I discovered that the cucumber sandwiches weren’t served in tea towels. As a result, the butter hadn’t set with the cucumbers right… Anyways, I made a big scene and set fire to some of the advertising trucks outside. I smashed this spotlight to pieces and so on. I had this loud maniacal laughing thing going on deep into that night. It was a real mess.

But, since I don’t get along well with people, I hadn’t invited anyone but myself to the Opening Ceremonies of This Book. So it wasn’t really that embarassing. I kept it under wraps and no one found out about the whole ordeal.

So you’ve got to know that synergy doesn’t actually mean synergy in this book. I can’t do normal synergy. No, in this book, synergy means cartoon foxes. What I’m saying is: this book will be starting off with an exorbitant amount of cartoon foxes.

And I will be counting on you to turn them into synergy.

Yeah, these are the two. My asthma’s kickin in so I’ve got to go take a puff of medicated air just now. Be with you in a moment.

I’m told that this chapter is best accompanied by a rag. Something you can mop your face with as the sweat pours off your face.

Indeed, we’ll be racing through the whole language. Like striking every match in a box as quickly as can be done.

1. Language and I MEAN Language

My conscience won’t let me call Ruby a computer language. That would imply that the language works primarily on the computer’s terms. That the language is designed to accomodate the computer, first and foremost. That therefore, we, the coders, are foreigners, seeking citizenship in the computer’s locale. It’s the computer’s language and we are translators for the world.

But what do you call the language when your brain begins to think in that language? When you start to use the language’s own words and colloquialisms to express yourself. Say, the computer can’t do that. How can it be the computer’s language? It is ours, we speak it natively!

We can no longer truthfully call it a computer language. It is coderspeak. It is the language of our thoughts.

Read the following aloud to yourself.

5.times { print "Odelay!" }

In English sentences, punctuation (such as periods, exclamations, parentheses) are silent. Punctuation adds meaning to words, helps give cues as to what the author intended by a sentence. So let’s read the above as: Five times print “Odelay!”.

2. The Parts of Speech

Just like the white stripe down a skunk’s back and the winding, white train of a bride, many of Ruby’s parts of speech have visual cues to help you identify them. Punctuation and capitalization will help your brain to see bits of code and feel intense recognition. Your mind will frequently yell Hey, I know that guy! You’ll also be able to name-drop in conversations with other Rubyists.

Try to focus on the look of each of these parts of speech. The rest of the book will detail the specifics. I give short descriptions for each part of speech, but you don’t have to understand the explanation. By the end of this chapter, you should be able to recognize every part of a Ruby program.

Variables

Any plain, lowercase word is a variable in ruby. Variables may consist of letters, digits and underscores.

x, y, banana2 or phone_a_quail are examples.

Variables are like nicknames. Remember when everyone used to call you Stinky Pete? People would say, “Get over here, Stinky Pete!” And everyone miraculously knew that Stinky Pete was you.

With variables, you give a nickname to something you use frequently. For instance, let’s say you run an orphanage. It’s a mean orphanage. And whenever Daddy Warbucks comes to buy more kids, we insist that he pay us one-hundred twenty-one dollars and eight cents for the kid’s teddy bear, which the kid has become attached to over in the darker moments of living in such nightmarish custody.

teddy_bear_fee = 121.08

Later, when you ring him up at the cash register (a really souped-up cash register which runs Ruby!), you’ll need to add together all his charges into a total.

total = orphan_fee + teddy_bear_fee + gratuity

Those variable nicknames sure help. And in the seedy underground of child sales, any help is appreciated I’m sure.

Numbers

The most basic type of number is an integer, a series of digits which can start with a plus or minus sign.

1, 23, and -10000 are examples.

Commas are not allowed in numbers, but underscores are. So if you feel the need to mark your thousands so the numbers are more readable, use an underscore.

population = 12_000_000_000

Decimal numbers are called floats in Ruby. Floats consist of numbers with a decimal place or scientific notation.

3.14, -808.08 and 12.043e-04 are examples.

Strings

Strings are any sort of characters (letters, digits, punctuation) surrounded by quotes. Both single and double quotes are used to create strings.

"sealab", '2021', or "These cartoons are hilarious!" are examples.

When you enclose characters in quotes, they are stored together as a single string.

Think of a reporter who is jotting down the mouthnoises of a rambling celebrity. “I’m a lot wiser,” says Avril Lavigne. “Now I know what the business is like—what you have to do and how to work it.”

 avril_quote = "I'm a lot wiser.  Now I know 
  what the business is like -- what you have 
  to do and how to work it."

So, just as we stored a number in the teddy_bear_fee variable, now we’re storing a collection of characters (a string) in the avril_quote variable. The reporter sends this quote to the printers, who just happen to use Ruby to operate their printing press.

 print oprah_quote
 print avril_quote
 print ashlee_simpson_debacle

Symbols

Symbols are words that look just like variables. Again, they may contain letters, digits, or underscores. But they start with a colon.

:a, :b, or :ponce_de_leon are examples.

Symbols are lightweight strings. Usually, symbols are used in situations where you need a string but you won’t be printing it to the screen.

You could say a symbol is a bit easier on the computer. It’s like an antacid. The colon indicates the bubbles trickling up from your computer’s stomach as it digests the symbol. Ah. Sweet, sweet relief.

Constants

Constants are words like variables, but constants are capitalized. If variables are the nouns of Ruby, then think of constants as the proper nouns.

Time, Array or Bunny_Lake_is_Missing are examples.

In English, proper nouns are capitalized. The Empire State Building. You can’t just move The Empire State Building. You can’t just decide that the Empire State Building is something else. Proper nouns are like that. They refer to something very specific and usually don’t change over time.

In the same way, constants can’t be changed after they are set.

EmpireStateBuilding = "350 5th Avenue, NYC, NY"

If we try to change the constant, Ruby will complain to us. Such things are frowned upon.

Methods

If variables and constants are the nouns, then methods are the verbs. Methods are usually attached to the end of variables and constants by a dot. You’ve already seen methods at work.

front_door.open

In the above, open is the method. It is the action, the verb. In some cases, you’ll see actions chained together.

front_door.open.close

We’ve instructed the computer to open the front door and then immediately close it.

front_door.is_open?

The above is an action as well. We’re instructing the computer to test the door to see if it’s open. The method could be called Door.test_to_see_if_its_open, but the is_open? name is succinct and just as correct. Both exclamation marks and question marks may be used in method names.

Method arguments

A method may require more information in order to perform its action. If we want the computer to paint the door, we should provide a color as well.

Method arguments are attached to the end of a method. The arguments are usually surrounded by parentheses and separated by commas.

front_door.paint( 3, :red )

The above paints the front door 3 coats of red.

Think of it as an inner tube the method is pulling along, containing its extra instructions. The parentheses form the wet, round edges of the inner tube. The commas are the feet of each argument, sticking over the edge. The last argument has its feet tucked under so they don’t show.

Like a boat pulling many inner tubes, methods with arguments can be chained.

front_door.paint( 3, :red ).dry( 30 ).close()

The above paints the front door 3 coats of red, dries for 30 minutes, and closes the door. Even though the last method has no arguments, you can still put parentheses if you like. There is no use dragging an empty inner tube, so the parentheses are normally dropped.

Some methods (such as print) are kernel methods. These methods are used throughout Ruby. Since they are so common, you won’t use the dot.

print "See, no dot."

Class methods

Like the methods described above (also called instance methods), class methods are usually attached after variables and constants. Rather than a dot, a double colon is used.

Door::new( :oak )

As seen above, the new class method is most often used to create things. In the above example, we’re asking Ruby to make a new oak door for us. Of course, Ruby has to have an understanding of how to make a door—as well as a wealth of timber, lumberjacks, and those long, wiggily, two-man saws.

Global variables

Variables which begin with a dollar sign are global.

$x, $1, $chunky and $CHunKY_bACOn are examples.

Most variables are rather temporary in nature. Some parts of your program are like little houses. You walk in and they have their own variables. In one house, you may have a dad that represents Archie, a travelling salesman and skeleton collector. In another house, dad could represent Peter, a lion tamer with a great love for flannel. Each house has its own meaning for dad.

With global variables, you can be guaranteed that the variable is the same in every little house. The dollar sign is very appropriate. Every American home respects the value of the dollar. We’re crazy for the stuff. Try knocking on any door in America and hand them cash. I can guarantee you won’t get the same reaction if you knock on a door and offer Peter, a lion tamer with a great love for flannel.

Global variables can be used anywhere in your program. They never go out of sight.

Instance variables

Variables which begin with an at symbol are instance variables.

@x, @y, and @only_the_chunkiest_cut_of_bacon_I_have_ever_seen are examples.

These variables are often used to define the attributes of something. For example, you might provide Ruby with the width of the front_door by setting the @width variable inside that front_door. Instance variables are used to define characteristics of a single object in Ruby.

Think of the at symbol as meaning attribute.

Class variables

Variables which begin with double at symbols are class variables.

@@x, @@y, and @@i_will_take_your_chunky_bacon_and_raise_you_two are examples.

Class variables, too, are used to define attributes. But rather than defining an attribute for a single object in Ruby, class variables give an attribute to many related objects in Ruby. If instance variables set attributes for a single front_door, then class variables set attributes for everything that is a Door.

Think of the double at prefix as meaning attribute all. Additionally, you can think of a swarm of AT-ATs from Star Wars, which are all commanded by Ruby. You change a class variable and not just one changes, they all change.

Blocks

Any code surrounded by curly braces is a block.

2.times { print "Yes, I've used chunky bacon in my examples, but never again!" } is an example.

With blocks, you can group a set of instructions together so that they can be passed around your program. The curly braces give the appearance of crab pincers that have snatched the code and are holding it together. When you see these two pincers, remember that the code inside has been pressed into a single unit.

It’s like one of those little Hello Kitty boxes they sell at the mall that’s stuffed with tiny pencils and microscopic paper, all crammed into a glittery transparent case that can be concealed in your palm for covert stationary operations. Except that blocks don’t require so much squinting.

The curly braces can also be traded for the words do and end, which is nice if your block is longer than one line.

 loop do
   print "Much better." 
   print "Ah.  More space!" 
   print "My back was killin' me in those crab pincers." 
 end

Block arguments

Block arguments are a set of variables surrounded by pipe characters and separated by commas.

|x|, |x,y|, and |up, down, all_around| are examples.

Block arguments are used at the beginning of a block.

{ |x,y| x + y }

In the above example, |x,y| are the arguments. After the arguments, we have a bit of code. The expression x + y adds the two arguments together.

I like to think of the pipe characters as representing a tunnel. They give the appearance of a chute that the variables are sliding down. (An x goes down spread eagle, while the y neatly crosses her legs.) This chute acts as a passageway between blocks and the world around them.

Variables are passed through this chute (or tunnel) into the block.

Ranges

A range is two values surrounded by parentheses and separated by an ellipsis (in the form of two or three dots).

(1..3) is a range, representing the numbers 1 through 3.

('a'..'z') is a range, representing a lowercase alphabet.

Think of it as an accordion which has been squeezed down for carrying. (Sure, you can build a great sense of self-worth by carrying around an unfolded accordion, but sometimes a person needs to wallow in self-doubt, carefully concealing the squeeze-box.) The parentheses are the handles on the sides of a smaller, handheld accordion. The dots are the chain, keeping the folds tightly closed.

Normally, only two dots are used. If a third dot is used, the last value in the range is excluded.

(0...5) represents the numbers 0 through 4.

When you see that third dot, imagine opening the accordion slightly. Just enough to let one note from its chamber. The note is that end value. We’ll let the sky eat it.

Arrays

An array is a list surrounded by square brackets and separated by commas.

[1, 2, 3] is an array of numbers.

['coat', 'mittens', 'snowboard'] is an array of strings.

Think of it as a caterpillar which has been stapled into your code. The two square brackets are staples which keep the caterpillar from moving, so you can keep track of which end is the head and which is the tail. The commas are the caterpillar’s legs, wiggling between each section of its body.

Once there was a caterpillar who had commas for legs. Which meant he had to allow a literary pause after each step. The other caterpillars really respected him for it and he came to have quite a commanding presence. Oh, and talk about a philanthropist! He was notorious for giving fresh leaves to those less-fortunate.

Yes, an array is a collection of things, but it also keeps those things in a specific order.

Hashes

A hash is a dictionary surrounded by curly braces. Dictionaries match words with their definitions. Ruby does so with arrows made from an equals sign, followed by a greater-than sign.

{'a' => 'aardvark', 'b' => 'badger'} is an example.

This time, the curly braces represent little book symbols. See how they look like little, open books with creases down the middle? They represent opening and closing our dictionary.

Imagine our dictionary has a definition on each of its pages. The commas represent the corner of each page, which we turn to see the next definition. And on each page: a word followed by an arrow pointing to the definition.

 {
   'name' => 'Peter',
   'profession' => 'lion tamer',
   'great love' => 'flannel'
 }

I’m not comparing hashes to dictionaries because you can only store definitions in a hash. In the example above, I stored personal information for Peter, the lion tamer with a great love for flannel. Hashes are like dictionaries because they can be very easy to search through.

Unlike arrays, the items in a hash are not kept in a specific order.

Regular Expressions

A regular expression (or regexp) is a set of characters surrounded by slashes.

/ruby/, /[0-9]+/ and /^\d{3}-\d{3}-\d{4}/ are examples.

Regular expressions are used to find words or patterns in text. The slashes on each side of the expression are pins.

Imagine if you had a little word with pins on both side and you held it over a book. You pass the word over the book and when it gets near a matching word, it starts blinking. You pin the regular expression onto the book, right over the match and it glows with the letters of the matching word.

Oh, and when you poke the pins into the book, the paper sneezes, reg-exp!

Regular expressions are much faster than passing your hand over pages of a book. Ruby can use a regular expression to search volumes of books very quickly.

Operators

You’ll use the following list of operators to do math in Ruby or to compare things. Scan over the list, recognize a few. You know, addition + and subtraction - and so on.

  ** !  ~  *  /  %  +  -  &  
  << >> |  ^  >  >= <  <= <=>
  || != =~ !~ && += -= == ===
  .. ... not and or          

Keywords

Ruby has a number of built-in words, imbued with meaning. These words cannot be used as variables or changed to suit your purposes. Some of these we’ve already discussed. They are in the safe house, my friend. You touch these and you’ll be served an official syntax error.

  alias   and     BEGIN   begin   break   case    class   def     defined 
  do      else    elsif   END     end     ensure  false   for     if 
  in      module  next    nil     not     or      redo    rescue  retry 
  return  self    super   then    true    undef   unless  until   when 
  while   yield 

Good enough. These are the illustrious members of the Ruby language. We’ll be having quite the junket for the next three chapters, gluing these parts together into sly bits of (poignant) code.

I’d recommend skimming all of the parts of speech once again. Give yourself a broad view of them. I’ll be testing your metal in the next section.

3. If I Haven't Treated You Like a Child Enough Already

I’m proud of you. Anyone will tell you how much I brag about you. How I go on and on about this great anonymous person out there who scrolls and reads and scrolls and reads. “These kids,” I tell them. “Man, these kids got heart. I never…” And I can’t even finish a sentence because I’m absolutely blubbering.

And my heart glows bright red under my filmy, translucent skin and they have to administer 10cc of JavaScript to get me to come back. (I respond well to toxins in the blood.) Man, that stuff will kick the peaches right out your gills!

So, yes. You’ve kept up nicely. But now I must begin to be a brutal schoolmaster. I need to start seeing good marks from you. So far, you’ve done nothing but move your eyes around a lot. Okay, sure, you did some exceptional reading aloud earlier. Now we need some comprehension skills here, Smotchkkiss.

Say aloud each of the parts of speech used below.

5.times { print "Odelay!" }

You might want to even cover this paragraph up while you read, because your eyes might want to sneak to the answer. We have a number 5, followed by a method .times. Then, the first crab pincers of a block. The kernel method print has no dot and is followed by a string "Odelay!". The final crab pincers close our block.

Say aloud each of the parts of speech used below.

exit unless "restaurant".include? "aura"

Like the print method, exit is a kernel method. If you were paying attention during the big list of keywords, you’ll know that unless is just such a keyword. The string "restaurant" is clung to by the method include?. And finally, the string "aura".

Say aloud each of the parts of speech used below.

['toast', 'cheese', 'wine']. each { |food| print( food.capitalize ) }

This caterpillar partakes of finer delicacies. An array starts this example. In the array, three strings 'toast', 'cheese', and 'wine'. The whole array is trailed by a method each.

Inside of a block, the block argument food, travelling down its little waterslide into the block. The method capitalize then capitalizes the first letter of the block argument, which has become variable food. This capitalized string is passed to kernel method print.

Look over these examples once again. Be sure you recognize the parts of speech used. They each have a distinct look, don’t they? Take a deep breath, press firmly on your temples. Now, let’s dissect a cow’s eye worth of code.

4. An Example to Help You Grow Up

Say aloud each of the parts of speech used below.

 require 'net/http'
 Net::HTTP.start( 'www.ruby-lang.org', 80 ) do |http|
     print( http.get( '/en/LICENSE.txt' ).body )
 end

The first line is a method call. The method called require is used. A string is passed to the method containing 'net/http'. Think of this first line of code as a sentence. We have told Ruby to load some helper code, the Net::HTTP library.

The next three lines all go together. The constant Net::HTTP refers to the library we loaded above. We are using the method start from the library. Into the method, we’re sending a string 'www.ruby-lang.org' and the number 80.

The word do opens a block. The block has one block variable http. Inside the block, the method print is called. What is being printed?

From the variable http, the method get is called. Into get, we pass a string containing the path '/en/LICENSE.txt'. Now, notice that another method is chained onto get. The method body. Then, the block closes with end.

Doing okay? Just out of curiousity, can you guess what this example does? Hopefully, you’re seeing some patterns in Ruby. If not, just shake your head vigorously while you’ve got these examples in your mind. The code should break apart into manageable pieces.

For example, this pattern is used a number of times:

variable . method ( method arguments )

You see it inside the block:

http.get( '/en/LICENSE.txt' )

We’re using Ruby to get a web page. You’ve probably used HTTP with your web browser. HTTP is the Hypertext Transfer Protocol. HTTP is used to transfer web pages across the internet. Conceptualize a bus driver that can drive across the internet and bring back web pages for us. On his hat are stitched the letters HTTP.

The variable http is that bus driver. The method is a message to the bus driver. Go get the web page called /en/LICENSE.txt.

So where you see the chain of methods:

http.get( '/en/LICENSE.txt' ).body

Since we’ll be getting back a web page from the http bus driver, you can read this in your brain as:

web page .body

And this bit of code:

print( http.get( '/en/LICENSE.txt' ).body )

This code gets the web page. We send a body message to the web page, which gives us all the HTML in a string. We then print that string. See how the basic dot-method pattern happens in a chain. The next chapter will explore all these sorts of patterns in Ruby. It’ll be good fun.

So, what does this code do? It prints the HTML for the Ruby home page to the screen. Using an web-enabled bus driver.

5. And So, The Quick Trip Came To An Eased, Cushioned Halt

So now we have a problem. I get the feeling that you are enjoying this way too much. And you haven’t even hit the chapter where I use jump-roping songs to help you learn how to parse XML!

If you’re already enjoying this, then things are really going bad. Two chapters from now you’ll be writing your own Ruby programs. In fact, it’s right about there that I’ll have you start writing your own role-playing game, your own file-sharing network (a la BitTorrent), as well as a program that will pull genuine random numbers from the Internet.

And you know (you’ve got to know!) that this is going to turn into an obsession. First, you’ll completely forget to take the dog out. It’ll be standing by the screen door, darting its head about, as your eyes devour the code, as your fingers slip messages to the computer.

Thanks to your neglect, things will start to break. Your mounds of printed sheets of code will cover up your air vents. Your furnace will choke. The trash will pile-up: take-out boxes you hurriedly ordered in, junk mail you couldn’t care to dispose of. Your own uncleanliness will pollute the air. Moss will infest the rafters, the water will clog, animals will let themselves in, trees will come up through the foundations.

But your computer will be well-cared for. And you, Smotchkkiss, will have nourished it with your knowledge. In the eons you will have spent with your machine, you will have become part-CPU. And it will have become part-flesh. Your arms will flow directly into its ports. Your eyes will accept the video directly from DVI-24 pin. Your lungs will sit just above the processor, cooling it.

And just as the room is ready to force itself shut upon you, just as all the overgrowth swallows you and your machine, you will finish your script. You and the machine together will run this latest Ruby script, the product of your obsession. And the script will fire up chainsaws to trim the trees, hearths to warm and regulate the house. Builder nanites will rush from your script, reconstructing your quarters, retiling, renovating, chroming, polishing, disinfecting. Mighty androids will force your crumbling house into firm, rigid architecture. Great pillars will rise, statues chiseled. You will have dominion over this palatial estate and over the encompassing mountains and islands of your stronghold.

So I guess you’re going to be okay. Whatdya say? Let’s get moving on this script of yours?

I’ve never seen the ham do anything but leak juice. Today, our business in Ambrose Caverns is with the elf. He is a crucial part of the next lessons. Let’s all make him feel welcome. Go start warming up your listening hats! (And please change out of those ridiculous stirrup pants.)

A prompt warning: this lesson is much slower. Stay with it. This will be a long, deep breath. The most crucial stage of your instruction. It may seem like you’re not learning much code at first. You will be learning concepts. By the end of this chapter, you will know Ruby’s beauty. The coziness of the code will become a down sleeping bag for your own solace.

1. The Leaf as a Status Symbol in Ambrose

Alright, Elf. Give us a quick rundown of the currency issues you’ve faced there in your kingdom.

Yeah, that’s not the way I remember it. This Elf was paging me constantly. When I refused to call him back, he somehow left a message on my pager. Meaning: it beeped a couple times and then printed out a small slip of paper. The slip said something to the effect of, “Get down here quick!” and also, “We’ve got to rid the earth of this scourge of enterpreneurial caterpillars, these twisted insect vikings are suffocating my blue crystals!”

Lately, the exchange rate has settled down between leaves and crystals. One treegrown note is worth five crystals. So the basic money situation looks like this:

 blue_crystal = 1
 leaf_tender = 5

This example is, like, totally last chapter. Still. It’s a start. We’re setting two variables. The equals sign is used for assignment.

Now leaf_tender represents the number 5 (as in: five blue crystals.) This concept right here is half of Ruby. We’re defining. We’re creating. This is half of the work. Assignment is the most basic form of defining.

You can’t complain though, can you Elf? You’ve built an empire from cashing your blue crystals into the new free market among the forest creatures. (And even though he’s an elf to us, he’s a tall monster to them.)

Nonono. Hang on a sec. You’re not ready for what the Elf here is doing in his caves. You’ll think it’s all positively inhumane, naughty, sick, tweeested, yada yada.

Now You’re Going to Hear the Animal Perfect Mission Statement Because This Is A Book And We Have Time And No Rush, Right?

Back, back, way back before speedboats, I owned a prize race horse who took a stumble on the track. She did ten front flips and crashed into a guy who was carrying a full jar of mayonnaisse. We had blood and mayonnaisse up and down the track. Needless to say, she was a disaster.

The vet took one look at her and swore she’d never walk again. Her legs were gone and the vet wouldn’t allow a legless horse to just sit around. We’d need to put her down. He swore his life and career on it, insisting we divide into two parallel lines. The people who could not refute the doctor’s claims on one side; those too stubborn to accept his infallable medical reasoning on the other. The Elf, his pet ham, and I were the only ones in that second line.

So while the others heaped up trophies and great wreaths around the horse, bidding it a fond farewell before the bullet came to take him home, the Elf and I frantically pawed the Internet for answers. We took matter into our own hands, cauterizing her leg wounds with live crawdads. It worked great! We now had a horse again. Or at least: a horse body with a crustaceous abdominal frosting.

She scurried everywhere after that and lived for years in pleasantly moist underground cavities.

Animal Perfect is now the future of animal enhancement. They build new animals and salvage old-style animals for parts. Of course, they’ve come a long ways. When Animal Perfect started, you’d see a full-grown bear walk into Animal Perfect and you’d see a full-grown bear with sunglasses walk out. Completely cheesy.

Stick around and you’ll see a crab with his own jet pack. That’s a new 2004 model jetcrab.

But now, the whole operation is up and running. And the cleanliness of the place is astonishing. All the equipment is so shiny. Everything is in chrome. Oh, and all the staff have concealed weapons. They’re trained to kill anyone who enters unannounced. Or, if they run out of bullets, they’re trained to pistol whip anyone who enters unannounced.

Elf, make me a starmonkey.

Some imaginary Ruby for you:

pipe.catch_a_star

Variable pipe. Method catch_a_star. A lot of Rubyists like to think of methods as a message. Whatever comes before the dot is handed the message. The above code tells the pipe to catch_a_star.

This is the second half of Ruby. Putting things in motion. These things you define and create in the first half start to act in the second half.

1. Defining things.
2. Putting those things into action.

So what if the star catching code works? Where does the star go?

captive_star = pipe.catch_a_star

See, it’s up to you to collect the miserable, little star. If you don’t, it’ll simply vanish. Whenever you use a method, you’ll always be given something back. You can ignore it or use it.

If you can learn to use the answers that methods give you back, then you will dominate.

Quickly then.

starmonkey = ratchet.attach( captive_monkey, captive_star )

The ratchet gets an attach message. What needs to be attached? The method arguments: the captive_monkey and the captive_star. We are given back a starmonkey, which we have decided to hang on to.

This is turning out to be such a short, little proggie that I’m just going to put it all together as one statement.

starmonkey = ratchet.attach( captive_monkey, pipe.catch_a_star ) + deco_hand_frog

See how pipe.catch_a_star is right in the arguments for the method? The caught star will get passed right to the ratchet. No need to find a place to put it. Just let it go.

2. Small and Nearly Worthless

The hotel here in Ambrose is no good at all. The beds are all lumpy. The elevator is tiny. One guy put all his bags in the elevator and found out there wasn’t room for him. He hit the button and chased up the stairs after it all. But the stairwell turned out to be too narrow and his shoulders got wedged going up.

The soap mini-bars they give you are sized down for elves, so it’s impossible to work up a lather. I hate it. I keep mistaking them for contact lenses.

I turned on the faucet and nothing came out. Thing is: Ambrose is a place with magical properties, so I took a chance. I put my hands under the spigot. Invisible, warm wetness. I felt the hurried sensation of running water, darting through my fingers. When I took my hands away, they were dry and clean.

It was an amazing nothingness to experience. It was just like nil.

Nil

In Ruby, nil represents an emptiness. It is without value. It isn’t zero. Zero is a number.

It’s Ruby’s own walking dead, a flatlined keyword. You can’t add to it, it doesn’t evolve. But it’s terribly popular. This skeleton’s smiling in all the pictures.

plastic_cup = nil

The above plastic_cup is empty. You could argue that the plastic_cup contains something, a nil. The nil represents the emptiness, though, so go ahead and call it empty.

Some of you who have programmed before will be tempted to say the plastic_cup is undefined. How about let’s not. When you say a variable is undefined, you’re saying that Ruby simply has no recollection of the variable, it doesn’t know the var, it’s absolutely non-existent.

But Ruby is aware of the plastic_cup. Ruby can easily look in the plastic_cup. It’s empty, but not undefined.

False

The cat Trady Blix. Frozen in emptiness. Immaculate whiskers rigid. Placid eyes of lake. Tail of warm icicle. Sponsored by a Very Powerful Pause Button.

The darkness surrounding Blix can be called negative space. Hang on to that phrase. Let it suggest that the emptiness has a negative connotation. In a similar way, nil has a slightly sour note that it whistles.

Generally speaking, everything in Ruby has a positive charge to it. This spark flows through strings, numbers, regexps, all of it. Only two keywords wear a shady cloak: nil and false draggin us down.

You can test that charge with an if keyword. It looks very much like the do blocks we saw in the last chapter, in that both end with an end.

 if plastic_cup
   print "Plastic cup is on the up 'n' up!" 
 end

If plastic_cup contains either nil or false, you won’t see anything print to the screen. They’re not on the if guest list. So if isn’t going to run any of the code it’s protecting.

But nil and false need not walk away in shame. They may be of questionable character, but unless runs a smaller establishment that caters to the bedraggled. The unless keyword has a policy of only allowing those with a negative charge in. Who are: nil and false.

 unless plastic_cup
   print "Plastic cup is on the down low." 
 end

You can also use if and unless at the end of a single line of code, if that’s all that is being protected.

 print "Yeah, plastic cup is up again!" if plastic_cup
 print "Hardly. It's down." unless plastic_cup

And another nice trick: stack the if and unless.

 print "We're using plastic 'cause we don't have glass." if plastic_cup unless glass_cup

This trick is a gorgeous way of expressing, Do this only if a* is true and *b isn’t true.

Now that you’ve met false, I’m sure you can see what’s on next.

True

approaching_guy = true

I saw true at the hotel buffet tables today. I cannot stand that guy. His stance is way too wide. And you’ve never met anyone who planted his feet so hard in the ground. He wears this corny necklace made out of shells. His face exudes this brash confidence. (You can tell he’s exerting all of his restraint just to keep from bursting into Neo flight.)

To be honest, I can’t be around someone who always has to be right. This true is always saying, “A-OK.” Flashing hang ten. And seriously, he loves that necklace. Wears it constantly.

As you’d suspect, he’s backstage at everything on the if event schedule.

print "Hugo Boss" if true acts like print "Hugo Boss".

Occassionally, if will haul out the velvet ropes to exercise some crowd control. The double equals gives the appearance of a short link of ropes, right along the sides of a red carpet where only true can be admitted.

 if approaching_guy == true
   print "That necklace is classic." 
 end

The double equals is simply an ID check. Do the gentleman at both ends of this rope appear to match?

In this way, you control who if lets in. If you have a hard time getting along with true as I do, you can heartily welcome false.

 if approaching_guy == false
   print "Get in here, you conniving devil." 
 end

Same goes for unless. The gateway is yours. Take possession of it.

Again, I Want You to Dominate

Now, you want a head trip? The double equals sign is a method. Can you guess how it works? Here, check it out with the dot and parens:

approaching_guy.==( true )

Ruby allows the shortcut, though. You can drop the dot and back away slowly.

Now, do you remember what you need to do to dominate in Ruby? Use the answers the methods give you.

 if nil.==( true )
   print "This will never see realization." 
 end

In the above, how is the method’s answer being used?

Let’s take the statement nil true. This will fail every time. No match. When there’s no match, the double equals method answers with false. A shake of the head. That answer is given to if, who can’t accept a false. The print never sees realization.

 at_hotel = true
 email = if at_hotel
           "why@hotelambrose.com" 
         else
           "why@drnhowardcham.com" 
         end

Even though if isn’t a method, if does give a return answer. Look at the above and wonder over what happens when at_hotel is true.

The if will return the answer given by the code it chooses to run. In the case of at_hotel being true, the first string, my e-mail address at Hotel Ambrose, will be returned. The else keyword marks code which will run, should if fail. If at_hotel is false, the if will answer with my e-mail address at Dr. N. Howard Cham’s office, where I take my apprenticeship.

Should you have several lines of code in an if or unless, only the answer from the last full statement will be used.

 email = if at_hotel
           address = "why" 
           address << "@hotelambrose" 
           address << ".com" 
         end

Three lines of code inside the if. The first line assigns a string with my name in it to a variable. The second and third lines add the rest of my e-mail address on to the end. The double less-than << is the concatenation operator. To concatenate is to append, or add to the end.

Just as we saw with the equality checker </code>, the concatenator is a method. After adding to the end of the string, the concatenator also <strong>answers with that very string</strong>. So, the third line, which could be read as <code>address.<<( ".com" ), gives back address, which the if then hands back for email’s assignment.

Here’s a question: what if the if fails? What if at_hotel is false in the above example? Is anything returned? Nothing is assigned to email, right?

Yes, nothing is returned. By which I mean: nil is returned. And often nil is a very useful answer.

 print( if at_hotel.nil?
          "No clue if he's in the hotel." 
        elsif at_hotel == true
          "Definitely in." 
        elsif at_hotel == false
          "He's out." 
        else
          "The system is on the freee-itz." 
        end )

You can use the nil? method on any value in Ruby. Again, think of it as a message. To the value: “Are you nil? Are you empty?”

If at_hotel is empty, Ruby doesn’t have any idea if I’m in the hotel or not. So if answers with the “No clue” string. In order to handle the true or false possibilities, the elsif keyword is used. While you can have only one if and one else, you can fill the inbetween with an exorbitant number of elsif keywords. Each elsif acts as a further if test. Checking for a positive charge.

If you’re doing okay at this point, then you’re in tip-top shape for the rest of the book. You have seen some pretty tough code in the last few examples. You strong fellow.

3. Chaining Delusions Together

You finish reading the above comic and retire to your daybed for reflection. It’s one of those canopy affairs which is always logjammed with pillows. You sit atop the pile, gazing out upon the world. You see the tall smokestacks belching wide spools of fume and haze. The tangled concourses of freeways smattered with swift, shimmering traffic is but a gently pulsing eye muscle from your vantage point.

It is all so fantastic. How the colors of the horizon spread across the landscape as a great mix of butter and grease with a tablespoon of vanilla extract.

Yet, for all of the beauty which beckons for your attention, the images of the Elf and his Olympic Hopeful return. And more especially, that order for 55,000 starmonkeys. 55,000 starmonkeys, you think. Fifty-five Thousand.

You think of just the number itself. 55,000. It’s walking down a road. It might be in a forest, you don’t know for sure as your eyes are fixed right on the number itself. It’s stopping and talking to people. To tennis players, to a men’s choral group. There is merriment and good feeling. When it laughs, its lower zeros quiver with glee.

You want to talk to it. You want to skip along that forest trail with it. You want to climb aboard a jet bound to Brazil with it. And after five days and four nights at the leisureful Costa do Sauipe Marriott Resort & Spa, to marry it, to bear a family of 55,000 starmonkeys with it. To take possession of Nigeria with it.

With a flying leap, you dismount your pillow tower of isolation. Scrambling with the key, you unlock your roll top desk and pull out a sheet of paper, holding it firmly upon the desk. You begin scribbling.

Take possession of Nigeria with my new 55,000 starmonkeys... Over it, build Nigeria-sized vegetarians only casino and go-cart arena... Wings… we could have our own special sauce on the wings that’s different... Mustard + codeine = Smotchkkiss’ Starry Starmonkey Glow Sauce... Franchise, franchise… logos... Employee instructional videos... When you give the customer change, let them reach inside the frog on your hand to get it... If they have no change, at least put their reciept some place where they have to touch the frog... We’re leveling the playing field here... Advertise cheap pizza, let’s make our money off soda... Collect all 4 frosted glasses...

Wow, the ideas are really coming out. You literally had to smack yourself to stop. We need to put these in a safe place. Actually, we should store them on your computer and mangle the words. You look out the window and watch for FBI. I’m going to start this script.

The Flipping Script

 print "Type and be diabolical: " 
 idea_backwards = gets.reverse

Let this script be your confidante. It will ask for evil plans and turn their letters backwards. The gets method is built into Ruby. It’s a kernel method like print. This method gets will pause Ruby to let you type. When you hit Enter, gets will then stop paying attention to your keyboard punchings and answer back to Ruby with a string that contains everything you typed.