除了超类之外,我想创建一个子类来为子类添加属性。这是我尝试过的:
第一版:
class Person
attr_reader :first_name, :last_name, :age
def initialize (first_name, last_name, age)
@first_name = first_name
@last_name = last_name
@age = age
end
end
class Musician < Person
attr_reader :first_name, :last_name, :age, :instrument
def initialize (first_name, last_name, age, instrument)
super
@instrument
end
end
第二版
class Person
ATTRS = ['first_name', 'last_name', 'age']
def attributes
ATTRS
end
end
class Musician < Person
ATTRS = ['instrument']
def attributes
super + ATTRS
end
end
这些都不起作用。