Fastest/One-liner way to list attr_accessors in Ruby?

Question

What\'s the shortest, one-liner way to list all methods defined with attr_accessor? I would like to make it so, if I have a class MyBaseClass, any

Answer 1

Class definitions

class MyBaseClass
  attr_writer :an_attr_writer
  attr_reader :an_attr_reader

  def instance_m
  end

  def self.class_m
  end
end

class SubClass < MyBaseClass
  attr_accessor :id

  def sub_instance_m
  end

  def self.class_sub_m
  end
end

Call as class methods

p SubClass.instance_methods - Object.methods    
p MyBaseClass.instance_methods - Object.methods

Call as instance methods

a = SubClass.new
b = MyBaseClass.new

p a.methods - Object.methods
p b.methods - Object.methods

Both will output the same

#=> [:id, :sub_instance_m, :id=, :an_attr_reader, :instance_m, :an_attr_writer=]
#=> [:an_attr_reader, :instance_m, :an_attr_writer=]

How to tell which are writer reader and accessor?

attr_accessor is both attr_writer and attr_reader

attr_reader outputs no = after the method name

attr_writer outputs an = after the method name

You can always use a regular expression to filter that output.