Question

In the following example, how can the amount_below_limit instance method access the argument to the max_weight scope?

# Model
class Elephant < ActiveRecord::Base
  scope :max_weight, lambda { |limit| where('weight <= ?', limit) }

  def amount_below_limit
    max_weight = # How can I see 1000 from here?
    max_weight - weight
  end
end

# Controller
@elephants = Elephant.max_weight(1000)

# View
<% @elephants.each do |elephant| %>
  <%= elephant.amount_below_limit %>
<% end %>

Answer 1

Thanks for your suggestions.

In the end, I refactored my code to make the parameter to max_weight an instance variable, which I then passed on to the amount_below_weight method.