CODEWITHSUNDEEP
rubyruby-1.9.3
Greg
Greg

Reputation: 6628

How to load file in object context

I'm playing with some meta-programming concepts and wonder if something I want to do is simply possible.

There's simple DLS for events, 

//test_events.rb
event 'monthly events are suspiciously high' do
  true
end

and the script should shout out when event returns true, I try to do this without polluting global namespace with method event, and any instance variables. So I try something like this: 

Dir.glob('*_events.rb').each do |file|

  MyClass = Class.new do
    define_method :event do |name, &block|
      @events[name] = block
    end
  end

  env = MyClass.new

  env.instance_eval{@events = {}}

  env.instance_eval{load(file)}

end

So for each *_events.rb file I would like to load it in context of MyClass (i know that with 2nd loop of Dir.glob#each it will complain about already defined const - not important now).

The problem is with env.instance_eval{load(file)} code in test_events.rb is run in Object context, because I get 

undefined method `event' for main:Object (NoMethodError)

Is there a way to do it? ( I try now in 1.9.3 but changing version up is not a problem since it's just exercise)

Upvotes: 1

Views: 736

Answers (1)

matt
matt

Reputation: 79723

instance_eval can take a String as its argument instead of a block, so rather than load (which as you suggest will load the file in the top level) you need to read the file contents into a string to pass in, something like:

env.instance_eval(File.read(file))

Upvotes: 4

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