CODEWITHSUNDEEP
ruby
Seralize
Seralize

Reputation: 1127

Lazy loading from subclass in Ruby

If I make @x lazily loaded in the parent class A it can be called and initialized just fine, but if I try to call it from A's subclass B, then it won't call @x's initialization method and returns nil. Why is that?

class A
  def x
    @x ||= 'x'
  end
end

puts A.new.x # 'x'

class B < A
  def use_x
    puts @x.inspect # nil
  end
end

Upvotes: 1

Views: 125

Answers (2)

sawa
sawa

Reputation: 168101

Because the method x is not called within use_x. Whether it is A or B is irrelevant. puts B.new.x would give the same result as it would with puts A.new.x.

Upvotes: 0

falsetru
falsetru

Reputation: 369094

Use x instead of directly accessing the instance variable @a.

class B < A
  def use_x
    puts x.inspect
  end
end

Upvotes: 2

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