Question

I thought that this question ( How to do attr_accessor_with_default in ruby? ) answered my question, but I’m not using ActiveRecord and after_initialize depends on it.

What’s the Ruby best practice for implementing a default value for an attr_accessor? Is this the closest thing to documentation about it? Should I stop using attr_accessor since it is private?

Answer 1

class Foo
  # class-level instance variable

  # setting initial value (optional)
  @class_var = 42  

  # making getter/setter methods on the class itself
  class << self
    attr_accessor :class_var
  end

  # instance-level variable getter/setter methods
  attr_accessor :inst_var
  def initialize
    # setting initial value (optional)
    @inst_var = 17
  end
end

p Foo.class_var
#=> 42
Foo.class_var = 99
p Foo.class_var
#=> 99

f1 = Foo.new
f2 = Foo.new
f2.inst_var = 1
p [f1.inst_var, f2.inst_var]
#=> [17,1]