attribute_method_suffix

Declares a method available for all attributes with the given suffix. Uses method_missing and respond_to? to rewrite the method.

#{attr}#{suffix}(*args, &block)

to

attribute#{suffix}(#{attr}, *args, &block)

An attribute#{suffix} instance method must exist and accept at least the attr argument.

class Person
  include ActiveModel::AttributeMethods

  attr_accessor :name
  attribute_method_suffix '_short?'
  define_attribute_methods :name

  private
    def attribute_short?(attr)
      send(attr).length < 5
    end
end

person = Person.new
person.name = 'Bob'
person.name          # => "Bob"
person.name_short?   # => true