module ActiveModel::AttributeMethods::ClassMethods

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

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

define_attribute_methods :name
attribute_method_suffix '_short?'
attr_accessor :name

include ActiveModel::AttributeMethods
class Person

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

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

to

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

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

def attribute_method_suffix(*suffixes, parameters: nil)
  self.attribute_method_matchers += suffixes.map! { |suffix| AttributeMethodMatcher.new(suffix: suffix, parameters: parameters) }
  undefine_attribute_methods
end