Class in Ruby

!macOS-11.1!ruby-2.7.2p137

Preface (Introduction)

As a basic idea of ​​object orientation,

--Capsulation --Inheritance --Polymorphism

there is.

This idea is incorporated not only in Ruby but also in Python and various languages.

Class

If you enter a name in the argument of the command created earlier, a greeting will be returned.

hello_method.rb


def hello name
  puts "Hello #{name}."
end

name = ARGV[0]
hello(name)

We will improve this and further classify it.

Get the name

In hello \ _method.rb, I tried to return the command argument, but with this, if nothing is passed,

> ruby hello_method.rb
-> Hello .

Only a greeting is returned.

It's lonely as it is, so when you prepare the gets \ _name method and do not pass anything to the command argument

Hello world.

I will return.

greeter.rb


def hello name
  puts "Hello #{name}."
end

def gets_name
  name = ARGV[0] || 'world'
  return name
end

name = gets_name
hello name

Classified

Class this code.

class_greeter.rb


class Greeter
  def initialize
    @name = gets_name
    puts_hello
  end

  def puts_hello #salute
    puts "Hello #{@name}."
  end

  def gets_name
    name = ARGV[0] || 'world'
    return name.capitalize
  end
end

Greeter.new

When you do this

> ruby class_greeter.rb
-> Hello World.

> ruby class_greeter.rb W
-> Hello W.

You can have something that returns the same output as before classifying.

here,

--class Greeter: Greeter class definition --def initialize: Function to initialize. Does it work like a constructor such as C ++? [email protected]: Member variable --Greeter.new: Create an instance of the Greeter class

Is the basis for classification in Ruby.

Reference material

Chart type ruby-VI (hello class)

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