strange class_eval behavior

rubyonrails-talk
1

hi again, all. I have the following plugin included in my active record model. What i'd like to do, is define a method inside class_eval which returns the options has that was passed into it via the acts_as_item :foo=>:bar in my model.

What i'm finding odd is that the self.foo method can access the config hash when printing it, but not when i try to return it.

puts "OK FOO: #{config[:asset_root]}" - outputs ok, whereas the return config raises a method or variable not found error.

Any ideas? best, paul.

    module ClassMethods       def acts_as_item(options = {})         include InstanceMethods

        config = {:asset_root=>"SOMEPATH"}         config.update(options) if options.is_a?(Hash)

        class_eval <<-EOE           def self.foo             puts "OK FOO: #{config[:asset_root]}"             return config           end         EOE       end     end

2

hi again, all. I have the following plugin included in my active record model. What i'd like to do, is define a method inside class_eval which returns the options has that was passed into it via the acts_as_item :foo=>:bar in my model.

What i'm finding odd is that the self.foo method can access the config hash when printing it, but not when i try to return it.

Two very different things are happening: with the puts config is being resolved just before class_eval is called: the string is interpolated and the result passed to class_eval. The return statement on the other hand is evaluated much later - when the foo method is actually called. config is no longer in scope and so you get an error.

Fred

3

Frederick Cheung wrote: