Merge pull request railsbridge#140 from tjgrathwell/ruby_for_beginners_site

Stepfile-style ruby only curriculum

Author: tjgrathwell

lib/step.rb

@@ -94,6 +94,18 @@ class Step < Erector::Widget
 .deploying>h1 {
   background-color: #B0DEE7;
 }
+.further-reading>h1 {
+  background-color: rgb(135, 229, 242);
+}
+
+table.bordered td,
+table.bordered tr {
+  border-style: solid;
+  border-width: 1px;
+  border-color: black;
+  padding-left: 5px;
+  padding-right: 5px;
+}
 
 .requirements>h1 {
   background-color: #93B5DA;
@@ -135,6 +147,13 @@ class Step < Erector::Widget
   }
 }
 
+.in_file > pre {
+  border: 4px solid #dde;
+  @include border-radius(4px);
+  background-color: gray;
+  color: white;
+}
+
 .result > pre {
   border: 4px solid #dde;
   @include border-radius(4px);
@@ -321,6 +340,7 @@ def todo todo_text
   ## special
 
   TERMINAL_CAPTION = "Type this in the terminal:"
+  IRB_CAPTION = "Type this in irb:"
   RESULT_CAPTION = "Expected result:"
   FUZZY_RESULT_CAPTION = "Approximate expected result:"
 
@@ -330,6 +350,29 @@ def console msg
       pre msg
     end
   end
+  
+  def irb msg
+    div :class => "console" do
+      span IRB_CAPTION
+      pre msg
+    end
+  end
+
+  def type_in_file filename, msg
+    div do
+      span "Type this in the file #{filename}:"
+      source_code :ruby, msg
+    end
+  end
+
+  def further_reading
+    div :class => "further-reading" do
+      h1 "Further Reading"
+      blockquote do
+        yield
+      end
+    end
+  end
 
   def result text
     div :class => "result" do

sites/ruby/arrays.step

@@ -0,0 +1,93 @@
+goals do
+  goal "Make some arrays and do stuff with them"
+  goal "Retrieve data from arrays"
+end
+
+step do
+  irb <<IRB
+fruits = ["kiwi", "strawberry", "plum"]
+IRB
+  message 'An array is a list of things in square brackets, separated by commas.'
+  message 'We generally call the individual things in an array **elements**.'
+  irb <<-IRB
+things = [5, 'tree', 19.5]
+things.length
+  IRB
+  message 'An array can contain all sorts of things, not just strings.'
+  message '`length` is a method that tells you how many **elements** are in an array.'
+  irb <<-IRB
+  empty_array = []
+  empty_array.length
+  IRB
+  message 'The simplest kind of array is the empty array.'
+end
+
+step do
+  irb <<IRB
+fruits[0]
+fruits[1]
+fruits[2]
+IRB
+  message 'Array elements are stored in order. You can retrieve them by using the square brackets to access them by their **index**.'
+  message 'Arrays are ordered: elements remain in the same order they started in.'
+  message 'Ruby starts counting at zero: the first element is `fruits[0]`.'
+  irb <<IRB
+fruits.first
+fruits.last
+IRB
+  message 'Ruby gives us some helpful ways to get the first and last element from an array.'
+end
+
+step do
+	irb <<IRB
+['salt'] + ['pepper']
+IRB
+  message 'Arrays can be added together with the plus operator.'
+  irb <<IRB
+fruits + ['mango']
+fruits
+IRB
+  message 'The plus operator doesn\'t modify the existing array, it makes a new one. How could you write that last piece of code to also modify the fruits array?'
+end
+
+step do
+  irb <<IRB
+fruits = ["kiwi", "strawberry", "plum"]
+fruits.push('apple')
+fruits.pop()
+IRB
+  message 'Ruby has many methods for modifying arrays. What did these two methods do?'
+end
+
+explanation do
+  message "Arrays are used whenever you need to work with a large group of similar items."
+  message 'A short list of methods for Array:'
+  table class: 'bordered' do
+    tr do
+      td 'length'
+      td 'how long is this array (how many elements)'
+    end
+    tr do
+      td 'first'
+      td 'get the first element of the array (same as array[0])'
+    end
+    tr do
+      td 'last'
+      td 'get the last element of the array (same as array[-1])'
+    end
+    tr do
+      td 'push'
+      td 'add a new element to the end of the array'
+    end
+    tr do
+      td 'pop'
+      td 'remove (and return) the element at the end of the array'
+    end
+  end
+end
+
+further_reading do
+  a "Ruby's documentation for Array", href: 'http://www.ruby-doc.org/core-1.9.3/Array.html'
+end
+
+next_step "hashes"

sites/ruby/command_line.step

@@ -0,0 +1,76 @@
+goals do
+  goal "Learn about the command line"
+  goal "Make a new directory"
+  goal "Browse some directories on your computer"
+  goal do 
+    rawtext md2html("Learn the commands `pwd`, `mkdir`, `ls`, `cd` and `man`")
+  end
+end
+
+step do
+  message 'Open up a command line application on your computer. On Macs, this program is called Terminal. On Windows, you might want to use the "Command Line With Ruby and Rails" shortcut that came with RailsInstaller.'
+  console "pwd"
+  message '`pwd` means "print working directory". It shows you what **directory** you\'re currently in. Directories are also often called **folders**.'
+  message '`pwd` can help orient you in the command line if you get lost somewhere in your computer.'
+end
+
+step do
+  irb 'mkdir railsbridge_ruby'
+  message '`mkdir` means **m**ake **d**irectory. You use mkdir when you want to create a new directory.'
+  message 'The command line is just one way of manipulating the files on your computer. Try to find the new directory you created in Finder or Windows Explorer.'
+  message 'If you get an error saying the directory already exists, maybe someone did these steps on your computer before. Don\'t fret.'
+end
+
+step do
+  console 'cd railsbridge_ruby'
+  message '`cd` means **c**hange **d**irectory. You use cd when you want to move from the current directory into some other directory.'
+end
+
+step do
+  message "If you're on a Mac or Linux computer:"
+  console 'cd ~'
+  message "`~` indicates your **home directory**, a directory owned by the account currently logged in to the computer. Your home directory might be something like `/home/sparklepants` (Linux) or `/Users/saucyfrank` (Mac)"
+  message "Practice moving in and out of various directories. Remember that you can always get back to your home with `cd ~`."
+end
+
+step do
+  console 'ls'
+  message '`ls` stands for **list**, and shows the contents of the current directory.'
+  message 'Since you moved back to your Home directory, you should see the newly-created railsbridge_ruby directory in the output of `ls`.'
+end
+
+step do
+  console 'man ls'
+  message '`man` stands for **manual** and shows you the documentation for a command. This can include various options used to run the command in different ways.'
+  message "If you see a colon at the bottom of your terminal when viewing a man page, it means you're in a **pager**. Pagers are special programs for showing text that spans multiple pages. You can press the up and down arrows to page through the text, or type `q` to exit."
+end
+
+explanation do
+  message "The command line is an essential tool for computer programmers. While daunting at first, it offers great flexibility in moving around your computer and manipulating files."
+  message "There are many, many, many more commands available on the command line than what we've seen here, but these are enough to get you going."
+  message 'Command summary:'
+  table class: 'bordered' do
+    tr do
+      td 'pwd'
+      td 'print working directory'
+      td 'print the full path to your current directory'
+    end
+    tr do
+      td 'ls'
+      td 'list directory'
+      td 'display the contents of the current directory'
+    end
+    tr do
+      td 'cd [directory]'
+      td 'change directory'
+      td 'make this directory the current directory'
+    end
+    tr do
+      td 'man [cmd]'
+      td 'manual'
+      td "show the manual for this command. press 'q' to quit."
+    end
+  end
+end
+
+next_step "irb"

sites/ruby/conditionals.step

@@ -0,0 +1,88 @@
+goals do
+  goal do 
+    rawtext(md2html('Use `gets` to get input from the user of your program.'))
+  end
+  goal 'Use a conditional statement to execute a branch of code only some of the time.'
+end
+
+step do
+  message 'Create a new file called conditionals_test.rb'
+  type_in_file 'conditionals_test.rb', <<-'CONTENTS'
+print "How many apples do you have? > "
+apple_count = gets.to_i
+puts "You have #{apple_count} apples."
+  CONTENTS
+  console 'ruby conditionals_test.rb'
+  message 'When prompted, type in a number of apples and press enter.'
+  message "`print` is like `puts` but doesn't make a new line after printing."
+  message "`gets`, or **get** **s**tring, pauses your program and waits for the user to type something and hit the enter key. It then returns the value back to your program and continues execution. Since the user could have typed anything ('banana', '19.2', '<<!!@@') we use to_i to ensure what comes out is an integer. If the user didn't type a valid integer, `to_i` returns `0`."
+end
+
+step do
+  message 'Continuing on from the end of conditionals_test.rb...'
+  type_in_file 'conditionals_test.rb', <<-'CONTENTS'
+if apple_count > 5
+  puts "Lots of apples!"
+else
+  puts 'Not many apples...'
+end
+  CONTENTS
+  console 'ruby conditionals_test.rb'
+  message 'The `if ... else ... end` construct is a way of changing which lines of your program get executed depending on your data.'
+  message 'Try running the program with different values for apple_count to see each side of the conditional get executed.'
+end
+
+step do
+  message 'What goes after the `if` is any expression that returns a **boolean**, (the values `true` or `false`). Here\'s some more expressions that return `true` or `false`:'
+  irb <<-IRB
+15 < 5
+10 == 12
+'foo' != 'bar'
+  IRB
+  irb <<-IRB
+'sandwich'.end_with?('h')
+'sandwich'.end_with?('z')
+[1,2,3].include?(2)
+[1,2,3].include?(9)
+  IRB
+  message 'Many methods return `true` or `false` as well. By convention, methods in Ruby that return booleans end with a question mark.'
+end
+
+step do
+  message 'You can nest a conditional in a loop, as well.'
+  message 'Create a new file called conditional_loops.rb'
+  type_in_file 'conditional_loops.rb', <<-'CONTENTS'
+fruits = ['apple', 'pear', 'apricot']
+fruits.each do |fruit|
+  if fruit.start_with?('a')
+    puts "#{fruit} begins with the letter a."
+  end
+end
+  CONTENTS
+  console 'ruby conditional_loops.rb'
+  message "Try changing this conditional so it only prints fruits with at least five letters in their name. Remember to change the string you're `puts`ing as well!"
+end
+
+step do
+    message 'Create a new file called while_loop.rb'
+    type_in_file 'while_loop.rb', <<-'CONTENTS'
+total = 0
+user_input = nil
+while user_input != 'stop'
+  print 'Enter a number to add to the total. > '
+  user_input = gets.chomp
+  total = total + user_input.to_i
+end
+puts "Your final total was #{total}!"
+    CONTENTS
+    console 'ruby while_loop.rb'
+    message "A **while** loop continues repeating until a certain statement is false. Here, the program continually asks us for numbers until we say the string 'stop'."
+    message "It's easy for a while loop to get out of control! If your loop body doesn't do anything to make the **while** condition false, your loop will run forever."
+end
+
+explanation do
+  message "Without some kind of conditional, your program would do the same thing every time. Conditionals let you choose to do different things depending on what data you have in hand."
+  message 'Now that you know *conditionals*, *loops*, *arrays*, *hashes* and *strings*, you can make some pretty complicated programs!'
+end
+
+next_step 'functions'

sites/ruby/functions.step

@@ -0,0 +1,28 @@
+goals do
+  goal "Create a function"
+  goal "Call a function"
+end
+
+step do
+  message 'Create a new file called area.rb'
+  type_in_file 'area.rb', <<-'CONTENTS'
+def circle_area(radius)
+  Math::PI * (radius ** 2)
+end
+
+print "What is the radius of your circle? > "
+radius = gets.to_i
+
+puts "Your circle has an area of #{circle_area(radius)}"
+  CONTENTS
+  console 'ruby area.rb'
+  message 'When prompted, type in a radius for your circle.'
+end
+
+explanation do
+  message "As your programs get more and more complicated, you'll want to group code into **functions** that can be called over and over again."
+  message "A **function** begins with **def**, followed by the function name. Next comes any **variables** it takes, followed by the actual body of the function. Lastly, function definitions are finished with the **end** keyword."
+  message "Pedantic Programmers might want to tell you that Ruby doesn't technically have **functions**, and everything in ruby is really a **method**. It is appropriate to slap these people."
+end
+
+next_step 'objects'