Question

I found an interesting problem: http://rubeque.com/problems/fixing-bad-code-the-wrong-way/solutions

Generally we have a simple class (notice that we don’t have attr_accessor here):

class Foo
  def itnialize(name)
    self.foo = name
  end

  def set_bar 
    self.bar = 'it will fail..'
  end
end

I thought that ruby will raise no method error when I call Foo.new but it passes without any problems. The code will fail when I try Foo.new.bar

How is it possible and how to access Foo.new.foo variable?

Answer 1

You have a typo and have miss-spelt initialize as itnialize so it won’t be being called – so no error.

It looks like you’re trying to create an instance variable – to do so you need, somewhere, to define it with the @ prefix. So you might do:

def initialize(name)
  @foo = name
end

which would then mean you are able to access @foo inside the class.

self.foo can only ever refer to a method foo, so you need to define that method if you want to call it, either explicitly or by using one of the attr variants.

However, in this case, you could just do

def set_bar
  @bar = 'it will succeed!'
end