From: Adam Anderson <adamandersonis@...>
Date: 2007-11-08T05:04:34+09:00
Subject: Re: instance_eval to evaluate methods inside a block in cont

This isn't really what I'm trying to do, however. Your example would 
mean that I would have to pass a backup to a block everytime. What I 
want to do is basically impossible unless I can change scoping rules, I 
think.

my_method do
  another_instance_method("foo")
  method_outside_of_instance("bar")
end

which would just be equivalent to

my_method do |lol|
  lol.another_instance_method("foo")
  method_outside_of_instance("bar")
end

where the lol object is just an instance of the class which has defined 
both my_method and another_instance_method.

I want any method to implicitly check the scope of the class in which 
the method is being called and *THEN* check the scope outside the class. 
This is just an exercise in making code more readable and require less 
typing, as far I am concerned.

If I use instance_eval then all the methods inside then only those 
instance methods will work. I am pretty much resigned to believing this 
is impossible. I'm always taking suggestions, though!


Thanks,
Adam

Gary Wright wrote:
> On Nov 7, 2007, at 3:58 AM, Adam Anderson wrote:
>> From what I am reading it would seem that this is just not a
>> possibility, however.
> 
> You could use method_missing in the implicit object to delegate
> the message to another object:
> 
> class A
>    def foo
>      warn "foo in #{self.inspect}"
>    end
>    def backup=(b); @backup = b; end
>    def method_missing(*args, &block)
>      if @backup
>        @backup.send(*args, &block)
>      else
>        super
>      end
>    end
> end
> 
> 
> class B
>    def bar
>      warn "bar in #{self.inspect}"
>    end
>    def with(x, &b)
>      x.backup = self
>      x.instance_eval &b
>    end
> end
> 
> a = A.new
> b = B.new.with(a) {
>        foo            # foo in instance of A
>        bar            # bar in instance of B
> }

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