Question

I have written a class in ruby and I wish to define the method [] to access its members (all members are public). For example, for the following simple class:

class Boy
  attr_accessor :name, :age
  def initialize(n, a)
    @name = n
    @age = a
  end
end

I wish the following to be the same

b = Boy.new(Tom, 23)
b.name        # Tom
b[:name]      # Tom

Any help please? Thanks in advance

Answer 1

class Boy
  attr_accessor :name, :age
  def initialize(n, a)
    @name = n
    @age = a
  end

  def [](key)
        instance_variable_get(key)
  end
end

b = Boy.new("Tom", 23)
b.name        # Tom
b[:@name]     # Tom

Or

class Boy
  attr_accessor :name, :age
  def initialize(n, a)
    @name = n
    @age = a
  end

  def [](key)
        public_send(key)
  end
end

b = Boy.new("Tom", 23)
b.name        # Tom
b[:name]      # Tom

And if you want to define []= method,

For the first style:

def []=(key, value)
    instance_variable_set(key, value)
end

For the second style:

def []=(key, value)
    public_send(key.to_s + '=', value)
end