Why use Ruby's attr_accessor, attr_reader and attr_writer?

Why use Ruby's attr_accessor, attr_reader and attr_writer?

ruby attributes attr-accessor

ruby

Rails: Update model attribute without invoking callbacks

ruby-on-rails ruby model attributes callback

ruby

Sum 2 hashes attributes with the same key

ruby hash attributes sum

ruby

Ruby: Boolean attribute naming convention and use

ruby attributes conventions boolean-expression

ruby

Array Attribute for Ruby Model

ruby database-design attributes migration ruby-on-rails-3.1

ruby

How to convert from a string to object attribute name?

ruby-on-rails ruby attributes

ruby

Naming conventions for boolean attributes

ruby-on-rails ruby attributes naming-conventions

ruby

How to initialize 'attr_accessor' attribute values? [duplicate]

ruby-on-rails ruby ruby-on-rails-3 attributes initialization

ruby