Ruby: dynamically generate attribute_accessor

ruby attr-accessor
Yannick Schall picture Yannick Schall · Sep 23, 2011 · Viewed 11.2k times · Source

I'm trying to generate the attr_reader from a hash (with nested hash) so that it mirror the instance_variable creation automatically.

here is what i have so far:

data = {:@datetime => '2011-11-23', :@duration => '90', :@class => {:@price => '£7', :@level => 'all'}}


class Event
 #attr_reader :datetime, :duration, :class, :price, :level
  def init(data, recursion)
   data.each do |name, value|
    if value.is_a? Hash
      init(value, recursion+1)
    else
      instance_variable_set(name, value)
      #bit missing: attr_accessor name.to_sym 
    end
  end
end

But i can't find out a way to do that :(

Answer

rdvdijk picture rdvdijk · Sep 23, 2011

You need to call the (private) class method attr_accessor on the Event class:

    self.class.send(:attr_accessor, name)

I recommend you add the @ on this line:

    instance_variable_set("@#{name}", value)

And don't use them in the hash.

    data = {:datetime => '2011-11-23', :duration => '90', :class => {:price => '£7', :level => 'all'}}

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