Question

I’m trying to create a custom attr_accessor, but can’t seem to get it to work. Instead of returning the value assigned to the writer, it returns the instance variable. Any ideas?

class Object
  def custom_attr_accessor(klass, attribute)
    ivar = "@#{attribute}".to_sym
    writer_body = lambda { |arg| instance_variable_set(ivar, arg) }
    reader_body = lambda { ivar }
    klass.send(:define_method, "#{attribute}=".to_sym, &writer_body) 
    klass.send(:define_method, "#{attribute}".to_sym, &reader_body)
  end
end

class Person
end

custom_attr_accessor(Person, :age)

me = Person.new
me.age = 100
puts me.age

=> @age

Answer 1

Just like you did a instance_variable_set, you need instance_variable_get:

    reader_body = lambda { instance_variable_get(ivar) }

BTW, extending Object and passing a class is not very pretty. Try to make it Persion. custom_attr_accessor(:age), that would be much more OOP.