1. This One's For the Disenfranchised

If you give me a number, which is any year from Dr. Cham’s life, I’ll give you a synopsis of that time period. And I’ll do it as a Ruby method, so it’s an independent piece, an isolated chunk of code which can be hooked up to the voice of a robotic volcano, when such a thing becomes the apex of authoritative voice talents.

Okay, so I need you to notice def and case and when. You’ve seen the Ranges, the closed accordions of 1895..1913, back in chapter 3. They contain both ends and in between. And the backslashes at the end of each line simply ignore the Enter key at the end of each line, assuring Ruby that there is more of this line to come.

So, please: def and case and when.

 def dr_chams_timeline( year )
   case year
   when 1894
     "Born." 
   when 1895..1913
     "Childhood in Lousville, Winston Co., Mississippi." 
   when 1914..1919
     "Worked at a pecan nursery; punched a Quaker." 
   when 1920..1928
     "Sailed in the Brotherhood of River Wisdomming, which journeyed \
      the Mississippi River and engaged in thoughtful self-improvement, \
      where he finished 140 credit hours from their Oarniversity." 
   when 1929
     "Returned to Louisville to pen a novel about time-travelling pheasant hunters." 
   when 1930..1933
     "Took up a respectable career insuring pecan nurseries.  Financially stable, he \
      spent time in Brazil and New Mexico, buying up rare paper-shell pecan trees.  Just \
      as his notariety came to a crescendo: gosh, he tried to buried himself alive." 
   when 1934
     "Went back to writing his novel.  Changed the hunters to insurance tycoons and the \
      pheasants to Quakers." 
   when 1935..1940
     "Took Arthur Cone, the Headmaster of the Brotherhood of River Wisdomming, as a \
      houseguest.  Together for five years, engineering and inventing." 
   when 1941
     "And this is where things got interesting." 
   end
 end

The def keyword. Here is our first method definition. A plain kernel method, which can be used anywhere in Ruby. And how do we run it?

 puts dr_chams_timeline( 1941 )

Which answers with “And this is where things got interesting.” It’s the same story again and again: use your answers. I’ve set things up above so that the case statement always answers with a string. And since the case statement is the final (and only) statement in the method, then the method answers with that string. Trickling water spilling down from ledge to ledge.

Let me be clear about the case statement. Actually, I should call it a case..when statement, since they cannot be used separately. The case keyword is followed by a value, which is compared against each of the values which follow when keywords. The first value to qualify as a match is the one the case uses and the rest are ignored. You can do the same thing with a bunch of if..elsif statements, but it’s wordier.

 case year
 when 1894
   "Born." 
 when 1895..1913
   "Childhood in Lousville, Winston Co., Mississippi." 
 else
   "No information about this year." 
 end

Is identical to:

 if 1894 === year
   "Born." 
 elsif 1895..1913 === year
   "Childhood in Lousville, Winston Co., Mississippi." 
 else
   "No information about this year." 
 end

The triple equals is a length of velvet rope, checking values much like the double equals. It’s just: the triple equals is a longer rope and it sags a bit in the middle. It’s not as strict, it’s a bit more flexible.

Take the Ranges above. (1895..1913) isn’t at all equal to 1905. No, the Range (1895..1913) is only truly equal to any other Range (1895..1913). In the case of a Range, the triple equals cuts you a break and lets the Integer 1905 in, because even though it’s not equal to the Range, it’s included in the set of Integers represented by the Range. Which is good enough in some cases, such as the timeline I put together earlier.

Which actually looked like a timeline, didn’t it? I mean, sure, dr_chams_timeline method is code, but it does read like a timeline, clean and lovely.

But Was He Sick??

You know, he had such bad timing. He was scattered as a novelist, but his ventures into alchemy were very promising. He had an elixir of goat’s milk and sea salt that got rid of leg aches. One guy even grew an inch on a thumb he’d lost. He had an organic health smoke that smelled like foot but gave you night vision. He was working on something called Liquid Ladder, but I’ve never seen or read anything else about it. It can’t have been for climbing. Who knows.

One local newspaper actually visited Dr. Cham. Their book reviewer gave him four stars. Really. She did an article on him. Gave him a rating.

Just know that Dr. N. Harold Cham felt terrible about his niece. He felt the shock treatment would work. The polio probably would have killed her anyway, but he took the chance.

On Sept. 9, 1941, after sedating her with a dose of phenacetin in his private operating room, he attached the conducting clips to Hannah’s nose, tongue, toes, and elbows. Assisted by his apprentice, a bespeckled undergraduate named Marvin Holyoake, they sprinkled the girl with the flakes of a substance the doctor called opus magnum. A white powder gold which would carry the current and blatantly energize the girl, forcing her blood to bloom and fight and vanquish.

But how it failed, oh, and how, when the lever was tossed, she arched and kicked—and KABLAM!—and BLOY-OY-OY-KKPOY! Ringlets of hair and a wall of light, and the bell of death rang. The experiment collapsed in a dire plume of smoke and her innocence (for weeks, everyone started out with, “And she will never have the chance…”) was a great pit in the floor and in their lungs.

To Hannah, I code.

 opus_magnum = true
 def save_hannah
   success = opus_magnum
 end

A method is its own island. And what goes on inside is unaffected by the simple variables around it. Dr. Cham couldn’t breach the illness of his niece, no more than an opus_magnum variable can penetrate the steely exterior of a method.

Should we run the save_hannah method, Ruby will squawk at us, claiming it sees no opus_magnum.

I’m talking about scope. Microscopes narrow and magnify your vision. Telescopes extend the range of your vision. In Ruby, scope refers to a field of vision inside methods and blocks.

A method’s def statement opens its vision. Variable names introduced there will be seen by the method and kept meaningful until its end closes its eyes. You can pass data into a method by using arguments and data can be returned from the method, but the names used inside the method are only good for its scope.

Some variables have wider scope. Global variables like $LOAD_PATH, which start with a cash symbol, are available in any scope. Instance variables like @names, which start with an at are available anywhere inside a class scope. Same goes for class variables like @@tickets. Class and instance variables will be explored in a moment.

Blocks have scope, but it’s a bit fuzzier. More flexible.

 verb = 'rescued'
 ['sedated', 'sprinkled', 'electrocuted'].
 each do |verb|
   puts "Dr. Cham " + verb + " his niece Hannah." 
 end
 puts "Yes, Dr. Cham " + verb + " his niece Hannah."

The block iterates (spins, cycles) through each of the Doctor’s actions. The verb variable changes with each pass. In one pass, he’s sedating. In the next, he’s powdering. Then, he’s electrocuting.

So, the question is: after the block’s over, will he have rescued Hannah?

 Dr. Cham sedated his niece Hannah.
 Dr. Cham sprinkled his niece Hannah.
 Dr. Cham electrocuted his niece Hannah.
 Yes, Dr. Cham electrocuted his niece Hannah.

Blocks are allowed to see variables in the vicinity. The block noticed that the verb variable existed and it overwrote its contents as it went along. When the block completed and its tiny life ended, the verb variable came out a changed creature.

If a block uses a variable which hasn’t been used previously, though, then that variable vanishes at the end of the block. The block’s scope closes and the variable goes with it. Say that verb wasn’t used before the block.

 ['sedated', 'powdered', 'electrocuted'].
 each do |verb|
   puts "Dr. Cham " + verb + " his niece Hannah." 
 end
 puts "Yes, Dr. Cham " + verb + " his niece Hannah."

Pulls an error: undefined local variable or method `verb'. Poof.

It must be something difficult, even for a great scientist, to carry away the corpse of a young girl whose dress is still starched and embroidered, but whose mouth is darkly clotted purple at the corners. In Dr. Cham’s journal, he writes that he was tormented by her ghost, which glistened gold and scorched lace. His delusions grew and he ran from hellhounds and massive vengeful, angelic hands.

Only weeks later, he was gone, propelled from these regrets, vanishing in the explosion that lifted him from the planet.

And even as you are reading this now, sometime in these moments, the bell jar craft of our lone Dr. Cham touched down upon a distant planet after a sixty year burn. As the new world came into view, as the curvature of the planet widened, as the bell jar whisked through the upset heavens, tearing through sheets of aurora and solar wind, Dr. Cham’s eyes were shaken open.

What you are witnessing is the landing of Dr. Cham on the planet Endertromb. From what I can gather, he landed during the cusp of the Desolate Season, a time when there really isn’t much happening on the planet. Most of the inhabitants find their minds locked into a listless hum which causes them to disintegrate into just vapid ghosts of one-part-wisdom and three-parts-steam for a time.

My modest grasp of the history and climate of Endertromb has been assembled from hanging around my daughter’s organ instructor, who grew up on the planet.

I frequently drill my daughter’s organ instructor in order to ensure that he can keep appointments adequately. That he can take house calls at odd hours and promptly answer emergency calls. When he finally revealed to me that he was an alien whose waking day consisted of five-hundred and forty waking hours, I was incredibly elated and opened a contractual relationship with him which will last into 2060.

For three days (by his pocket watch’s account), Dr. Cham travelled the dark shafts of air, sucking the dusty wind of the barren planet. But on the third day, he found the Desolate Season ending and he awoke to a brilliant vista, decorated with spontaneous apple blossoms and dewy castle tiers.

2. A Castle Has Its Computers

Our intrepid Doctor set off for the alien castle, dashing through the flowers. The ground belted past his heels. The castle inched up the horizon. He desired a stallion, but no stallion appeared. And that’s how he discovered that the planet wouldn’t read his mind and answer his wishes.

As my daughter’s organ instructor explained it, however, the planet could read minds and it could grant wishes. Just not both at the same time.

One day as I quizzed the organ maestro, he sketched out the following Ruby code on a pad of cheese-colored paper. (And queer cheese smells were coming from somewhere, I can’t say where.)

 require 'endertromb'
 class WishMaker
   def initialize
     @energy = rand( 6 )
   end
   def grant( wish )
     if wish.length > 10 or wish.include? ' '
       raise ArgumentError, "Bad wish." 
     end
     if @energy.zero?
       raise Exception, "No energy left." 
     end
     @energy -= 1
     Endertromb::make( wish )
   end
 end

This is the wish maker.

Actually, no, this is a definition for a wish maker. To Ruby, it’s a class definition. The code describes how a certain object will work.

Each morning, the wish maker starts out with up to five wishes available for granting. A new WishMaker is created at sun up.

 todays_wishes = WishMaker.new

The new method is a class method which creates a new, blank object. It also calls the object’s initialize method automatically. In the WishMaker definition, you’ll see the initalize method, which contains a single line of code: @energy = rand( 6 ).

The rand( 6 ) picks a number between 0 and 5. This number will represent the number of wishes left in the day. So, occassionally there are no wishes available from the wish maker.

The random number is assigned to an instance variable which is named @energy. This instance variable will be available any time throughout the class. The variable can’t be used outside the scope of the class.

In chapter three, we briefly looked at instance variables and decided to respect them as attributes. (The at symbol could mean attribute.) Instance variables can used to store any kind of information, but they’re most often use to store bits of information about the object represented by the class.

In the above case, each wish maker for the day has its own energy level. If the wish maker were a machine, you might see a gauge on it that points to the energy left inside. The @energy instance variable is going to act as that gauge.

 todays_wishes = WishMaker.new
 todays_wishes.grant( "antlers" )

Okay, step back and ensure you understand the example here. The WishMaker class is an outline we’ve laid out for how the whole magic wish program works. It’s not the actual genie in the bottle, it’s the paperwork behind the scenes. It’s the rules and obligations the genie has to live by.

It’s todays_wishes that’s the genie in the bottle. And here we’re giving it a wish to grant. Give us antlers, genie. (If you really get antlers from this example, I don’t want to hear about it. Go leap in meadows with your own kind now.)

In the last chapter, the drill was: Ruby has two halves.

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

What are the actions in Ruby? Methods. And now, you’re having a lick of the definition language built-in to Ruby. Method definitions using def. Class definitions using class.

At this point in your instruction, it’s easier to understand that everything in Ruby is an object.

 number = 5
 print number.next                  # prints '6'

 phrase = 'wishing for antlers'
 print phrase.length                # prints '19'

 todays_wishes = WishMaker.new
 todays_wishes.grant( "antlers" )

And, consequently, each object has a class behind the scenes.

 print 5.class                       # prints 'Integer'
 print 'wishing for antlers'.class   # prints 'String'
 print WishMaker.new.class           # prints 'WishMaker'

Dr. Cham never saw the wish maker as he hustled across the landspace. It lay far beyond his landing in the valley of Sedna. Down sheer cliffs stuffed with layers of thicket, where you might toss your wish (written on a small 1” x 6” slip), down into the gaping void. Hopefully it will land on a lizard’s back, sticking to its spindly little horn.

And let’s say your wish makes it that far. Well, then, down the twisted wood goes the skinny salamander, scurrying through the decaying churches which had been pushed over that steep canyon ledge once and for all. And the expired priest inside, who weathered the fall as well, will kill the little amphibian—strangle it to death with a blessed gold chain—and save it for the annual Getting To Know You breakfast. He’ll step on your precious little wish and, when the thieves come, that slip will still be there, stuck on his sole. Of course, the thieves’ preferred method of torture is to cut a priest in thin deli-shaved slices from top to bottom. Who can cull evidence from that? And when they chop that last thin slice of shoe sole, they’ll have that rubber scalp in hand for good luck and good times. But they canoe much too hard, these thieves. They slap their paddles swiftly in the current to get that great outboard motor mist going. But the shoe sole is on a weak chain, tied to one man’s belt. And a hairy old carp leaps, latches on to that minute fraction of footwear. And the thieves can try, but they don’t see underwater. If they could, they’d see that mighty cable, packed with millions of needly fiber optics. Indeed, that fish is a peripheral plugged right into the core workings of the planet Endertromb. All it takes is one swallow from that fish and your wish is home free!

And that’s how wishes come true for children in this place.

Once my daughter’s organ instructor had drawn up the class for the wish maker, he then followed with a class for the planet’s mind reader.

 require 'endertromb'
 class MindReader
   def initialize
     @minds = Endertromb::scan_for_sentience
   end
   def read
     @minds.collect do |mind|
        mind.read
     end
   end
 end

Much as you’ve seen before, the initalize happens when a new MindReader object is created. This initialize gathers scans the planet for mindshare. It looks like these minds are stored in an array, since they are later iterated over using the collect method.

Both the wish maker and the mind reader refer to a class named Endertromb. This class is stored in a file endertromb.rb, which is loaded with the code: require 'endertromb'. Often you’ll use other classes to accomplish part of your task. Most of the latter half of this book will explore the wide variety of helpful classes that can be loaded in Ruby.

Dr. Cham Ventures Inside

But as Dr. Cham neared the castle, although the planet was aware of his thoughts, sensing his wonderment and anticipation, all Dr. Cham felt was deadness. He tromped up the steps of its open gate and through the entrance of the most beautiful architecture and was almost certain it was deserted.

For a while he knocked. Which paid off.

He watched the baby whale rise like a determined balloon. He marvelled at his first alien introduction and felt some concern that it had passed so quickly. Well, he would wait inside.

As he stepped through the castle door, he felt fortunate that the door hadn’t been answered by a huge eagle with greedy talons, eager to play. Or a giant mouse head. Or even a man-sized hurricane. Just a tubby little choo-choo whale.

“Not a place to sit down in this castle,” he said.

At first, he had thought he had just entered a very dim hallway, but as his eyes adjusted, he saw the entrance extended into a tunnel. The castle door had opened right into a passage made of long, flat slabs of rock. Some parts were congruous and resembled a corridor. Other parts narrowed, and even tilted, then finally tipped away out of view.

The passage was lit by small doorless refrigerators, big enough to hold an armful of cabbage, down by his feet. He peered inside one, which was hollow, illuminated along all sides, and turning out ice shards methodically.

He pawed the ice chips, which clung dryly to his fingertips, and he scrubbed his hands in the ice. Which left some muddy streaks on his hands, but satisfied a small part of his longing to bathe. How long had it been? Ten years? Thirty?

Along the passage, long tubes of cloth cluttered some sections. Later, bright pixel matter in porcelain scoops and buckets.

He happened upon a room which had been burrowed out of the tunnel which had a few empty turtle shells on the ground and a large illuminated wall. He stared into the room, bewildered. What could this be? In one state of mind, he thought of having a seat on a shell. This could be the entrace at last, some kind of receiving room. On the other hand, spiders could pour out of the shell’s hollow when he sat. He moved on.

Meal in a Castle’s Pocket

As he journeyed along the passageways (for the central tunnel forked and joined larger, vacuous caverns), he picked up themes in some locations. Groups of rooms infested with pumping machinery. Cloth and vats of glue dominated another area. He followed voices down a plush, pillowed cavity, which led him to a dead end: a curved wall with a small room carved at eye-level.

He approached the wall and, right in the cubby hole, were two aardvarks eating at a table.

They gazed at him serenely, both munching on some excavated beetle twice their size, cracked open and frozen on its back on the table.

“Hello, little puppets,” he said, and they finished their bites and kept looking with their forks held aloof.

“I wish my niece Hannah were here to meet you,” he told the attentive miniature aardvarks. “She’d think you were an intricate puppet show.” He peered in at the dining area, shelves with sets of plates, hand towels. Half of a tiny rabbit was jutting out from the top a machine, creamy red noodles were spilling out underneath it. A door at the back of the room hung ajar. Dr. Cham could see a flickering room with chairs and whirring motors through the door.

“Any child would want this dollhouse,” he said. “Hannah, my niece, as I mentioned, she has a wind-up doll that sits at a spindle and spins yarn. It’s an illusion, of course. The doll produces no yarn at all.”

One of the aardvarks opened a trapdoor in the floor and pressed a button down inside, which lit. Then, a small film projector slowly came up on a rod. The other aardvark sat and watched Dr. Cham.

“But Hannah still reaches down into the dollhouse and collects all the imaginary yarn into a bundle. Which she takes to her mother, my sister, who is very good at humoring Hannah. She sews a dress to the doll’s dimensions, which Hannah takes back to the doll.

“And she tells the doll, ‘Here, look, your hard work and perserverance has resulted in this beautiful dress. You can now accept the Chief of Police’s invitation to join him tonight at the Governor’s Mansion.’ And she has a doll in a policeman’s uniform who plays the part of the Chief. He’s too scrawny to be an actual Chief, that would require quite a bit of plastic.”

The aardvark responsible for the film projector loaded a reel and aimed the projector at the back wall. The film spun to life and the aardvark took a seat. A green square appeared on the wall. The attentive aardvark stared at Dr. Cham still.

“Your films are coloured,” said Dr. Cham. “What a lovely, little life.”

The film played on: a blue square. Then, a red circle. Then, an orange square. The attentive aardvark turned away, watched the screen change to a pink triangle, and both aardvarks resumed eating.

A purple star. A red square. With quietness settling, Dr. Cham could hear notes droning from the projector. Like a slow, plodding music box trying to roll its gears along the train tracks.

“Yes, enjoy your supper,” said Dr. Cham and he politely tipped his head away, marching back up the path he’d taken.

Another Dead End Where Things Began

He found himself lost in the castle’s tunnels. Nothing looked familiar. He wasn’t worried much, though. He was on another planet. He would be lost regardless.

He wound through the tunnels, attempting to recall his paths, but far too interested in exploring to keep track of his steps. He followed a single tunnel deep, down, down, which slanted so steeply that he had to leap across ledges and carefully watch his footholds. The gravity here seemed no different than Earth. His legs were pulled into slides just as easily.

Although he had no absolute way of knowing where he was, he felt certain that he had left the castle’s boundaries. This deep, this long of a walk. It had been an hour since he’d entered through the door. And, as the tunnel wound back up, he was sure that he would emerge into a new dwelling, perhaps even a manhole which he could peek out from and see the castle. Perhaps he shouldn’t have come so far down this route. He hoped nothing was hibernating down here.

The tunnel came to a stop. A dark, dead end.

He had time. So he read the book. He read of the foxes and their pursuit of the porcupine who stole their pickup truck. He read of the elf and the ham. He saw the pictographs of himself and found he could really relate to his own struggles. He even learned Ruby. He saw how it all ended.

Were I him, I couldn’t have stomached it. But he did. And he pledged in his bosom to see things out just as they happened.

3. The Continued Story of My Daughter's Organ Instructor

I know you may be alarmed to hear that I have a daughter. You think my writing is indicative of a palsied or infantile mind. Well, please rest. I don’t have a daughter. But I can’t let that stop me from sorting out her musical training.

As I was related these elaborate histories of the planet Endertromb, I found myself wandering through hallways, running my fingertips along the tightly buttoned sofas and soaking myself in the saturated bellowings of the pipes, as played by my daughter’s organ instructor. His notes resounded so deep and hollow in the walls of his manor that I began to casually mistake them for an ominous silence, and found it even easier to retreat into deep space with my thoughts. To think upon the ancient planet and its darker philosophies: its flesh temples, tanned from the dermal remains of its martyrs; its whale cartels, ingesting their enemies and holding them within for decades, dragging them up and down the staircases of ribs; its poison fogs and its painful doorways; and, the atrocious dynasties of The Originals, the species which claims fathership to all of the intellegent beings across the universe.

But, eventually, I’d hear those pipes of a higher octave sing and I’d be back in the very same breezy afternoon where I’d left.

How interesting that even the breeze of our planet is quite a strange thing to some outsiders. For he had also told me of the travellers from Rath-d, who ventured to Earth five centuries ago, but quickly dissipated in our air currents since they and their crafts and their armor were all composed of charcoal.

I had sat at the organ, listening to his faint tales of his colony, while he punctuated his symphonies to greater volumes and the story would disappear for awhile, until the coda came back around. He spoke of he and his brothers piling into the hollow of his mother’s tail and tearing the waxy crescent tissue from the inner wall. Juicy and spongy and syrupy soap which bleached their mouths and purged their esophagus as it went down. They chewed and chomped the stuff and it foamed. After they ate, they blew bubbles at each other, each bubble filled with a dense foam, which they slept upon. And early in the morning, when mother opened her tail again, she watched serenely as her babies lay cradled in the stew of dark meatballs and sweet, sticky froth.

He spelled out all the tastes of Endertromb. Of their salmon’s starchy organs, which cooked into a pasta, and its eyes which melted into rich cream. Of their buttermelon with tentacles. And he was just beginning to appreciate the delicacies as a child, only to be lifted from a schoolyard by a pair of upright pygmy elephants who reached at him, through the heavens, and snatched upon his collar with a vast length of crane.

They transplanted him on Earth, led him from their craft, trumpeting their snouts loudly for the city of Grand Rapids to hear, then left, weeping and embracing each other.

“But, strangely (em-pithy-dah), I learned upon, played upon (pon-shoo) the organs on my home (oth-rea) planet,” he said.

My daughter’s organ instructor speaks these extra words you see in parentheses. Who knows if they are from his native tongue or if they are his own soundful hiccups. He keeps another relic from Endertromb as well: he has twelve names.

“No, (wen-is-wen),” he said. “I have one name (im-apalla) which is said (iff) many-many different ways.”

I call him Paij-ree in the morning and Paij-plo in the later evening. Since it is day as I write, I will call him Paij-ree here.

Mumble-Free Earplugs

So I told Paij-ree, “Paij-ree, I am writing a book. To teach the world Ruby.”

“Oh, (pill-nog-pill-yacht) nice,” he said. He’s known Ruby longer than I have, but still: I will be my daughter’s Ruby instructor.

And I said, “Paij-ree, you are in the book. And the stories of your planet.” I talk to him like he’s E.T. I don’t know why. Just like how I said next, “And then maybe someday you can go home to your mom and dad!”

To which he said, “(pon-shoo) (pon-shoo) (em-pithy-dah).” Which is his way of speaking out loud his silence and awe.

He wanted to see what I’d written, so I showed him this short method I’ve written for you.

 def wipe_mutterings_from( sentence )
   while sentence.include? '('
     open = sentence.index( '(' )
     close = sentence.index( ')', open )
     sentence[open..close] = '' if close
   end
 end

“Can you see what this does, Paij-ree? Any old Smotchkkiss can use this method to take all the incoherent babblings out of your speaking,” I said.

And I fed something he said earlier into the method.

 what_he_said = "But, strangely (em-pithy-dah), 
   I learned upon, played upon (pon-shoo) the 
   organs on my home (oth-rea) planet." 
 wipe_mutterings_from( what_he_said )
 print what_he_said

And it came out as a rather plain sentence.

 But, strangely , 
 I learned upon, played upon the
 organs on my home planet.

“You shouldn’t use that (wary-to) while loop,” he said. “There are lovelier, (thopt-er), gentler ways.”

In the wipe_mutterings_from method, I’m basically searching for opening parentheses. When I find one, I scan for a closing paren which follows it. Once I’ve found both, I replace them and their contents with an empty string. The while loop continues until all parentheses are gone. The mutterings are removed and the method ends.

“Now that I look at this method,” I said. “I see that there are some confusing aspects and some ways I could do this better.” Please don’t look down on me as your teacher for writing some of this code. I figure that it’s okay to show you some sloppy techniques to help you work through them with me. So let’s.

Okay, Confusing Aspect No. 1: This method cleans a string. But what if we accidentally give it a File? Or a number? What happens? What if we run wipe_mutterings_from( 1 )?

If we give wipe_mutterings_from the number 1, Ruby will print the following and exit.

 NoMethodError: undefined method `include?' for 1:Fixnum
         from (irb):2:in `wipe_mutterings_from'
         from (irb):8

What you see here is a rather twisted and verbose (but at times very helpful) little fellow called the backtrace. He’s a wound-up policeman who, at the slightest sign of trouble, immediately apprehends any and all suspects, pinning them against the wall and spelling out their rights so quickly that none can quite hear it all. But it’s plain that there’s a problem. And, of course, it’s all a big misunderstanding, right?

When Ruby reads you these Miranda rights, listen hardest to the beginning. The first line is often all you need. In this first line is contained the essential message. And in the above, the first line is telling us that there is no include? method for the number 1. Remember, when we were talking about the reverse method in the last chapter? Back then, I said, ”a lot of methods are only available with certain types of values.” Both reverse and include? are methods which work with strings but are meaningless and unavailable for numbers.

To be clear: the method tries to use to the number. The method will start with sentence set to 1. Then, it hits the second line: while sentence.include? '('. Numbers have no include? method. Great, the backtrace has shown us where the problem is. I didn’t expect anyone to pass in a number, so I’m using methods that don’t work with numbers.

See, this is just it. Our method is its own little pocket tool, right? It acts as its own widget independent of anything else. To anyone out there using the wipe_mutterings_from method, should they pass in a number, they’ll be tossed this panic message that doesn’t make sense to them. They’ll be asked to poke around inside the method, which really isn’t their business. They don’t know their way around in there.

Fortunately, we can throw our own errors, our own exceptions, which may make more sense to someone who inadvertantly hands the wrong object in for cleaning.

 def wipe_mutterings_from( sentence )
   unless sentence.respond_to? :include?
     raise ArgumentError, 
       "cannot wipe mutterings from a #{ sentence.class }" 
   end
   while sentence.include? '('
     open = sentence.index( '(' )
     close = sentence.index( ')', open )
     sentence[open..close] = '' if close
   end
 end

This time, if we pass in a number (again, the number 1), we’ll get something more sensible.

 ArgumentError: cannot wipe mutterings from a Fixnum
         from (irb):3:in `wipe_mutterings_from'
         from (irb):12

The respond_to? method is really nice and I plead that you never forget it’s there. The respond_to? checks any object to be sure that it has a certain method. It then gives back a true or false. In the above case, the incoming sentence object is checked for an include? method. If no include? method is found, then we raise the error.

You might be wondering why I used a symbol with respond_to?. I used a symbol :include? instead of a string 'include?'. Actually, either will work with respond_to?.

Usually symbols are used when you are passing around the name of a method or any other Ruby construct. It’s more efficient, but it also catches the eye. The respond_to? asks Ruby to look inside itself and see if a method is available. We’re talking to Ruby, so the symbol helps denote that. It’s not a big deal, Ruby just recognizes symbols quicker than strings.

Now, Confusing Aspect No. 2: Have you noticed how our method changes the sentence?

 something_said = "A (gith) spaceship." 
 wipe_mutterings_from( something_said )
 print something_said

Did you notice this? In the first line of the above code, the something_said variable contains the string "A (gith) spaceship.". But, after the method invocation, on the third line, we print the something_said variable and by then it contains the cleaned string "A spaceship.".

How does this work? How does the method change the string? Shouldn’t it make a copy of the string before changing it?

Yes, absolutely, it should! It’s bad manners to change strings like that. We’ve used gsub and gsub! in the last chapter. Do you remember which of those two methods is a destructive method, which changes strings directly?

Either we need to call this method wipe_mutterings_from! (as a courtesy to all the other good folks out there that might use this method) or change the method to work on a copy of the string rather than the real thing. Which is an easy change! We just need to dup the string.

 def wipe_mutterings_from( sentence )
   unless sentence.respond_to? :include?
     raise ArgumentError, 
       "cannot wipe mutterings from a #{ sentence.class }" 
   end
   sentence = sentence.dup
   while sentence.include? '('
     open = sentence.index( '(' )
     close = sentence.index( ')', open )
     sentence[open..close] = '' if close
   end
   sentence
 end

The dup method makes a copy of any object. Look at that line we added again on its own:

 sentence = sentence.dup

What a peculiar line of code. How does sentence become a copy of sentence? Does it erase itself? What happens to the original sentence? Does it disappear?

Remember that variables are just nicknames. When you see sentence = "A (gith) spaceship.", you see Ruby creating a string and then giving that string a nickname.

Likewise, when you see sentence = sentence.dup, you see Ruby creating a new string and then giving that string a nickname. This is handy inside your method because now sentence is a nickname for a new copy of the string that you can safely use without changing the string that was passed into the method.

You’ll see plenty of examples of variable names being reused.

 x = 5
 x = x + 1
 # x now equals 6

 y = "Endertromb" 
 y = y.length
 # y now equals 10

 z = :include?
 z = "a string".respond_to? z
 # z now equals true

And, yes, sometimes objects disappear. If you can’t get to an object through a variable, then Ruby will figure you are done with it and will get rid of it. Periodically, Ruby sends out its garbage collector to set these objects free. Every object is kept in your computer’s memory until the garbage collector gets rid of it.

Oh, and one more thing about dup. Some things can’t be dup’d. Numbers, for instance. Symbols (which look like :death) are identical when spelled the same. Like numbers.

Also, some of the special variables: nil, true, false. These are things that Ruby won’t let you alter, so there’s so point making a copy anyway. I mean, imagine if you could change false to be true. The whole thing becomes a lie.

Perhaps Confusing Aspect No. 3 is a simple one. I’m using those square brackets on the string. I’m treating the string like it’s an Array or Hash. I can do that. Because strings have a [] method.

When used on a string, the square brackets will extract part of the string. Again, slots for a forklift’s prongs. The string is a long shelf and the forklift is pulling out a slab of the string.

Inside the brackets, we pass the index. It’s the label we’ve placed right between the prongs where the worker can see it. When it comes to strings, we can use a variety of objects as our index.

 str = "A string is a long shelf of letters and spaces." 
 puts str[0]       # prints 65 (the character code for an 'A')
 puts str[0..-1]   # prints 'A string is a long shelf of letters and spaces.'
 puts str[1..-2]   # prints ' string is a long shelf of letters and spaces'
 puts str[1, 3]    # prints 'A s'
 puts str['shelf'] # prints 'shelf'

Alright, the last Confusing Aspect No. 4: this method can be sent into an endless loop. You can give this method a string which will cause the method to hang and never come back. Take a look at the method. Can you throw in a muddy stick to clog the loop?

 def wipe_mutterings_from( sentence )
   unless sentence.respond_to? :include?
     raise ArgumentError, 
       "cannot wipe mutterings from a #{ sentence.class }" 
   end
   sentence = sentence.dup
   while sentence.include? '('
     open = sentence.index( '(' )
     close = sentence.index( ')', open )
     sentence[open..close] = '' if close
   end
   sentence
 end

Here, give the muddy stick a curve before you jam it.

 muddy_stick = "Here's a ( curve." 
 wipe_mutterings_from( muddy_stick )

Why does the method hang? Well, the while loop waits until all the open parentheses are gone before it stops looping. And it only replaces open parentheses that have a matching closing parentheses. So, if no closing paren is found, the open paren won’t be replaced and the while will never be satisfied.

How would you rewrite this method? Me, I know my way around Ruby, so I’d use a regular expression.

 def wipe_mutterings_from( sentence )
   unless sentence.respond_to? :gsub
     raise ArgumentError, 
       "cannot wipe mutterings from a #{ sentence.class }" 
   end
   sentence.gsub( /\([-\w]+\)/, '' )
 end

Do your best to think through your loops. It’s especially easy for while and until loops to get out of hand. Best to use an iterator. And we’ll get to regular expressions in time.

In summary, here’s what we’ve learned about writing methods:

1. Don’t be surprised if people pass unexpected objects into your methods. If you absolutely can’t use what they give you, raise an error.
2. It’s poor etiquette to change objects your method is given. Use dup to make a copy. Or find a method like gsub that automatically makes a copy as it does its job.
3. The square brackets can be used to lookup parts inside any Array, Hash or String objects, as these objects provide a [] method. Also, since these objects provide a []= method, the square brackets can be used in assignment (on the left-hand side of the equals sign) to change the parts of those objects.
4. Watch for runaway loops. Avoid while and until if you can.

The Mechanisms of Name-Calling

Forthwith there is a rustling in the trees behind Paij-ree’s house and it turns out to be a man falling from the sky. His name is Doug and he sells cats.

So, just as he comes into to view, when his shadow (and the shadows of the cats tied to his foot) obscures the bird on the lawn that we’re trying to hit with a racquetball, as he’s squeezing a wisp of helium from his big balloon, we shout, “Hello, Doug!”

And he says, “Hello, Gonk-ree! Hello, Why!”

Paij-ree checks his pockets to be sure he has the dollar-twenty-seven he’ll need in order to buy the three cats he’ll need to keep the furnace stoked and the satellite dish turning. These cats generate gobs of static once Paij-ree tosses them in the generator, where they’ll be outnumbered by the giant glass rods, which caress the cats continually—But, wait! Did you see how the cat broker called him Gonk-ree?

And he calls him Gonk-ree in the morning and Gonk-plo at night.

So the suffix is definitely subject to the sunlight. As far as I can tell, the prefix indicates the namecaller’s relationship to Paij-ree.

 class String

   # The parts of my daughter's organ
   # instructor's name.
   @@syllables = [
     { 'Paij' => 'Personal',
       'Gonk' => 'Business',
       'Blon' => 'Slave',
       'Stro' => 'Master',
       'Wert' => 'Father',
       'Onnn' => 'Mother' },
     { 'ree'  => 'AM',
       'plo'  => 'PM' }
   ]

   # A method to determine what a
   # certain name of his means.
   def name_significance
     parts = self.split( '-' )
     syllables = @@syllables.dup
     signif = parts.collect do |p|
       syllables.shift[p]
     end
     signif.join( ' ' )
   end

 end

Now I’ve gone beyond just showing you sloppy code. Here be a grave debauchery and a crime against nature. A crime most languages won’t allow you to commit. We’re changing the String, one of the core classes of Ruby!

“I know this is a bit dangerous,” I said, when I passed this one under Paij-ree’s nose. “I hope nobody gets hurt.”

“Every Smotchkkiss must taste what this (kep-yo-iko) danger does,” he said. “Dogs and logs and swampy bogs (kul-ip), all must be tasted.” And he took a swig of his Beagle Berry marsh drink.

So what is it that I’m adding to the String class? Two things: a class variable and a method. A normal instance method.

I like to look at the at symbol as a character meaning attribute. The double at stands for attribute all. A class variable. All instances of a class can look at this variable and it is the same for all of them. The @@syllables variable is an Array that can now be used inside the String class.

The new method is name_significance and this new method can be used with any string.

print "Paij-ree".name_significance prints out Personal AM.

As you can see, Paij-ree is a personal name. A name friends use in the early hours.

Make sure you see the line of code which uses self. This is a special variable, a variable which represents the object whose method you are calling. To simplify things a bit, let’s try making a method which breaks up a string on its dashes.

 class String
   def dash_split
     self.split( '-' )
   end
 end

Again, here’s a method which can be used with any string.

"Gonk-plo".dash_split return the Array ['Gonk', 'plo'].

Using self marks the beginning of crossing over into many of the more advanced ideas in Ruby. This is definition language. You’re defining a method, designing it before it gets used. You’re preparing for the existence of an object which uses that method. You’re saying, “When dash_split gets used, there will be a string at that time which is the one we’re dash-splitting. And self is a special variable which refers to that string.”

Ruby is a knockout definition language. A succulent and brain-splitting discussion is coming your way deeper in this book.

Most often you won’t need to use self explicitly, since you can call methods directly from inside other method definitions.

 class String
   def dash_split; split( '-' ); end
 end

In the name_significance method, find the loop. Learning about Array#collect is essential. Let’s look close.

 signif = parts.collect do |p|
   syllables.shift[p]
 end

The parts Array contains the separated name. ['Paij', 'plo'], for instance. We’re iterating through each item in that Array with collect. But collect steps beyond what each does. Like each, collect slides each item down the chute as a block variable. And then, at the end of the block, collect keeps the answer the block gives back and adds it to a new Array. The collect method is the perfect way of building a new Array which is based on the items in an existing Array.

Doug has three cats for sale. One is twelve cents, one is sixty-three cents, one is nine cents. Let’s see how much each cat would cost if we added a 20% tip.

 catsandtips = [0.12, 0.63, 0.09].collect { |catcost| catcost + ( catcost * 0.20 ) }

I say Paij-ree’s property is a very charming section of woods when it’s not raining cats and Doug. For many days, Paij-ree and I camped in tents by the river behind his house, subsisting on smoked blackbird and whittling little sleeping indians by the dusklight. On occassion he would lose a game of spades and I knew his mind was distracted, thinking of Endertromb. All of this must have been stirring inside of him for sometime. I was the first ear he’d ever had.

“I just came from Ambrose,” I said. “Sort of my own underground home, a place where elves strive to perfect animals.”

He mumbled and nodded. “You can’t be (poth-in-oin) part of (in) such things.”

“You think we will fail?”

“I (preep) have been there before,” he said. And then, he spoke of the Lotteries.

4. The Goat Wants to Watch a Whole Film

The elevator had opened into a green room full of shelves and file cabinets. Reels of tape and film canisters and video tape everywhere. Dr. Cham hadn’t a clue what most of it was. All he saw was a big, futuristic mess.

He called out again, stumbling through alleys of narrow shelves, “Hello-o-o?? I’m looking for intellegent life! I’m a space traveller!” He tripped when his foot slid right into a VCR slot. “Any other beings I can communicate with?”

Hand cupped around mouth, he yelled, “Hello-o-o?”

“Crying out loud.” The sleepy goat came tromping down the aisle.

“I hate that book,” said the goat. “I believe the author is disingenuous.”

“Really?” asked Dr. Cham.

“I’m sure it’s all true. It’s just so heavily embellished. I’m like: Enough already. I get it. Cut it out.”

“I’m not quite sure what to make of it,” said the Doctor. “It seems like an honest effort. I actually wrote something in Ruby back there.”

“It doesn’t give goats a very good name,” said the goat.

“But you are the only goat in the book,” said the Doctor.

“And I’m totally misquoted.”

The goat closed his mouth and Dr. Cham held his heart.

“I’m actually very literate,” said the goat. “Albeit, more recently, I’ve switched to movies. I love foreign films. One of my relatives just brough back Ishtar from your planet. Wow, that was excellent.”

 we want a tambourine!
            /
           |  we want all a tambourine!
           |      /
           \__  |
         /  o o \__/\__/\_
       /.           \ o o \____
        /'      ----/          \
 _____ /  '    / /.\\   #------/
        /     /        /     \\
              /       ///
       /so               \
            /\   \me time\\..
        /pp/  \s these pictur\\
       /es/   \don't w\ \ork out\
      ***      *** right but i
        think this time
           they did
             ooo o
              oo
             o
          o
       {o}
    ^

“I haven’t been to my planet in a long time. It would be difficult to consider it my home at this stage.”

“Well, Warren Beatty is delightful. His character is basically socially crippled. He actually tries to kill himself, but Dustin Hoffman sits in the window sill and starts crying and singing this totally hilarious heartbreak song. I’ve got it here, you should see it.”

“Can I get something to eat?” asked the Doctor. And he still felt filthy.

“How about we watch a film and you can have a buttermelon with tentacles?” said the goat.

So, they worked their way back toward the goat’s projector. Back by the freezer locker, they sat on a giant rug and broke off the appendages of frozen buttermelons. The shell was solid, but once it cracked, rich fruit cream was in abundance. Sweet to taste and a very pleasant scent.

“First film, you’ve got to see,” said the goat. “Locally filmed and produced. I’m good friends with the lady who did casting. Dated her for awhile. Knew everyone who was going to play the different roles long before it was announced.”

The goat set the projector by Dr. Cham. “I’ve got the music on the surround sound. You can man the knob.”

Dr. Cham’s mind wandered at this point in the presentation, just as the land war mounted between the two throngs of animal settlers. The details of their wars and campaigns continued to consume the spool of transparent film that Dr. Cham was feeding through the projector.

War after war after war. The Sieging of Elmer Lake. The Last Stand of Newton P. Giraffe and Sons. Dog Invasion of Little Abandoned Cloud. No animals died in these wars. Most often an attack consisted of bopping another animal on the head. And they philipped each other’s noses. But, believe me, it was humiliating.

Blasted crying shame. Things could have worked out.

The Birth of an Object

“Don’t worry,” said the goat, anxious to sway Dr. Cham’s attention back to the film. “Things do work out.”

In Ruby, the Object is the very center of all things. It is The Original.

 class ToastyBear < Object; end

The angle bracket indicates inheritance. This means that the new ToastyBear class is a new class based on the Object class. Every method that Object has will be available in ToastyBear. Constants available in Object will be available in ToastyBear.

But every object inherits from Object. The code…

 class ToastyBear; end

Is identical to…

 class ToastyBear < Object; end

Inheritance is handy. You can create species of objects which relate to each other. Often, when you’re dissecting a problem, you’ll come across various objects which share attributes. You can save yourself work by inheriting from classes which already solve part of that problem.

You may have a UnitedStatesAddress class which stores the address, city, state, and zip code for someone living in the United States. When you start storing addresses from England, you could add a UnitedKingdomAddress class. If you then ensure that both addresses inherit from a parent Address class, you can design your mailing software to accept any kind of address.

 def mail_them_a_kit( address )
   unless address.is_a? Address
     raise ArgumentError, "No Address object found." 
   end
   print address.formatted
 end

Also, inheritance is great if you want to override certain behaviours in a class. For example, perhaps you want to make your own slight variation to the Array class. You want to enhance the join method. But if you change Array#join directly, you will affect other classes in Ruby that use Arrays.

So you start your own class called ArrayMine, which is based on The Original Array.

 class ArrayMine < Array
   # Build a string from this array, formatting each entry
   # then joining them together.
   def join( sep = $,, format = "%s" )
     collect do |item|
       sprintf( format, item )
     end.join( sep )
   end
 end

ArrayMine is now a custom Array class with its own join method. Array is the superclass of ArrayMine. Every object has a superclass method where you can verify this relationship.

 irb> ArrayMine.superclass
   => Array

Perfect. We manage a hotel and we have an Array of our room sizes: [3, 4, 6]. Let’s get it nicely printed for a brochure.

 rooms = ArrayMine[3, 4, 6]
 print "We have " + rooms.join( ", ", "%d bed" ) + " rooms available."

Which prints, “We have 3 bed, 4 bed, 6 bed rooms available.”

Dr. Cham was looking around for a bathroom, but archival video tape was everywhere. He eventually found a place, it may have been a bathroom. It had a metal bin. More importantly, it was dark and out of eyesight.

While he’s in there, let me add that while The Originals slaughtered The Invaders to prove their rights as First Creatures, the Ruby Object doesn’t have any such dispute. It is the absolute king Object the First.

Watch.

 irb> Class.superclass
   => Module
 irb> Kernel.class
   => Module
 irb> Module.superclass
   => Object
 irb> Object.superclass
   => nil

Even Class is an Object! See, although classes are the definition language for objects, we still call class methods on them and treat them like objects occassionally. It may seem like a dizzying circle, but it’s truly a very strict parentage. And it ensures that when you alter the Object, you alter everything in Ruby. Which is impossibly scary and all-powerful and cataclysmic and awesome! Ruby does not restrict you, my sister, my brother!

Between Class and Object, do you see Module? If Object is the king, the one who has sired every other part of Ruby, then Module is the poor waifish nun, shielding and protecting all her little Ruby townspeople children. (To complete the analogy: Class is the village school teacher and Kernel is the self-important colonel.)

The whole point of Module’s existence is to give food and shelter to code. Methods can stay dry under Module’s shawl. Module can hold classes and constants and variables of any kind.

“But what does a Module do?” you ask. “How is it gainfully employed??”

“That’s all it does!!” I retort, stretching out my open palms in the greatest expression of futility known to man. “Now hear me—for I will never speak it again—that Module Mother Superior has given these wretched objects a place to stay!!”

 # See, here is the module -- where else could our code possibly stay?
 module WatchfulSaintAgnes

   # A CONSTANT is laying here by the doorway.  Fine.
   TOOTHLESS_MAN_WITH_FORK = ['man', 'fork', 'exposed gums']

   # A Class is eating, living well in the kitchen.
   class FatWaxyChild; end

   # A Method is hiding back in the banana closet, God knows why.
   def timid_foxfaced_girl; {'please' => 'i want an acorn please'}; end

 end

Now you have to go through Saint Agnes to find them.

 >> WatchfulSaintAgnes::TOOTHLESS_MAN_WITH_FORK
 => ["man", "