learn ruby #43 @Ruby-KANSAI #55

person.rb

#
#
#
class Person; end

obj = Person.new
  # => #<Person:0x0000010104a108>
obj.class   # => Person
Person.ancestors
  # => [Person, Object, PP::ObjectMixin, Kernel, BasicObject]
Person.superclass   # => Object

#
#
#
class Person
  def initialize name
    @name = name
  end
end

matz = Person.new('matz')
  # => #<Person:0x000001010463a0 @name="matz">


#
#
#
class Person
  attr_reader :name
end

matz.name       # => "matz"


#
#
#
class Person
  def initialize name, born = nil
    @name, @born = name, born
  end
  attr_accessor :born
end

matz.methods.map(&:to_s).grep(/born/)
  # => ["born", "born="]


#
#
matz.born = Time.local(1965, 4, 14)
dhh = Person.new('dhh',
        Time.local(1979, 10, 15))

matz.born
  # => 1965-04-14 00:00:00 +0900
dhh.born
  # => 1979-10-15 00:00:00 +0900


#
#
#
class Person
  def age
    (Time.now.strftime('%Y%m%d').to_i -
     @born.strftime('%Y%m%d').to_i) /
      10000
  end
end
matz.age    # => 47
dhh.age     # => 32


#
#
#
matz.to_s   # => "#<Person:0x000001010463a0>"
matz.method(:to_s)  # => #<Method: Person(Kernel)#to_s>
Person.ancestors    # => [Person, Object, Kernel, BasicObject]

class Person
  def to_s
    "#{@name}(#{age})"
  end
end
matz.to_s   # => "matz(47)"
dhh.to_s    # => "dhh(32)"


#
#
#
person = Marshal.load(Marshal.dump matz)

person == matz  # => false
person == dhh   # => false


#
#
#
class Person
  include Comparable
  def <=> o
    @name <=> o.name
  end
end
person == matz  # => true
person == dhh   # => false
matz > dhh      # => true


#
#
#
people = [matz, dhh]

people.sort   # => [dhh(32), matz(47)]


#
#
#
h = {matz => "Ruby", dhh => "Rails"}

h[matz]     # => "Ruby"
h[dhh]      # => "Rails"

key = Marshal.load(Marshal.dump matz)
key == matz # => true
h[key]      # => nil


#
#
#
class Person
  def hash
    code = 17
    code = 37 * code + @name.hash
    code = 37 * code + @born.hash
  end
end
matz.hash   # => 25157996556348736046
dhh.hash    # => 78705111758323992282


#
#
#
class Person
  def eql? o
    return false unless @name.eql? o.name
    return false unless @born.eql? o.born
    true
  end
end
key.eql? matz   # => true
key.eql? dhh    # => false


#
#
#
h = {matz => "Ruby", dhh => "Rails"}

h[matz]     # => "Ruby"
h[dhh]      # => "Rails"

h[key]      # => "Ruby"


#
#
#
class Person
  protected :born
end

# matz.born

# # ~> -:172:in `<main>': protected method `born' called for matz(47):Person (NoMethodError)