val = 5 if false

class Employee
@empId
end 

 1module Company
2 @@companyName = "Hello Ruby."
3
4 class Employee
5  def display
6   print "#@companyName"
7  end
8 end
9
10 class Department
11  def display
12   print "#@companyName"
13  end
14 end
15end

 1module Company
2 class Employee
3  def display
4   # nil
5   print "#$companyName"
6   $companyName = "Hello Ruby."
7  end
8 end
9
10 class Department
11  def display
12   # Hello Ruby.
13   print "#$companyName"
14  end
15 end
16end

# 當(dāng)前方法的執(zhí)行主體
print "#{self}"
# NilClass類的唯一實(shí)例
print "#{nil}"
# TrueClass 類的唯一實(shí)例
print "#{true}"
# FalseClass 類的唯一實(shí)例
print "#{false}"
# 當(dāng)前源文件名
print "#{__FILE__}"
# 當(dāng)前源文件中的行號(hào)
print "#{__LINE__}" 

1# 屬于 Object 的常量
2GroupName = "心守家園"
3
4module Site
5 SiteUrl = "http://www.you2v.com"
6
7 class Sichuan
8 Add = "涼山"
9 # 引用屬于 Object 的常量
10 print "#{::GroupName}"
11 end
12end
13
14# 直接引用類名、模塊名
15# 引用屬于 Object 的模塊時(shí)可以省略“::”
16print "#{::Site}\n#{Site::Sichuan}"
17# 屬于模塊的常量
18print "#{Site::SiteUrl}"
19# 屬于類的常量
20print "#{Site::Sichuan::Add}"