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Groups > comp.lang.ruby > #3343

Re: class_eval doesn't find const_missing

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Stephen Prater wrote in post #994391:
> 
http://stackoverflow.com/questions/3015947/ruby-how-does-constant-lookup-work-in-instance-eval-class-eval
>
> Const lookup varies between 1.8, 1.9.1, and 1.9.2.
>
> Basically, constants are lexically scoped.
>
> You can use "const_get" I believe to lookup your constant in the
> current binding rather than in the lexical scope.
>

That works for me in ruby 1.9.2:

DummyClass.class_eval do
  puts const_get(:NAME)
end

--output:--
dummy constant

That makes sense because the call is really:

  puts self.const_get(:NAME)

and because self is equal to DummyClass, that is equivalent to:

  puts DummyClass.const_get(:NAME)

which like class_eval'ing a string does the lookup in the "directory" 
DummyClass.

-- 
Posted via http://www.ruby-forum.com/.

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Thread

class_eval doesn't find const_missing Andrew Berkeley <andrew.berkeley.is@googlemail.com> - 2011-04-21 14:20 -0500
  Re: class_eval doesn't find const_missing Stephen Prater <stephenp@agrussell.com> - 2011-04-21 16:34 -0500
    Re: class_eval doesn't find const_missing 7stud -- <bbxx789_05ss@yahoo.com> - 2011-04-21 18:14 -0500
  Re: class_eval doesn't find const_missing 7stud -- <bbxx789_05ss@yahoo.com> - 2011-04-21 17:38 -0500
    Re: class_eval doesn't find const_missing 7stud -- <bbxx789_05ss@yahoo.com> - 2011-04-21 18:29 -0500
  Re: class_eval doesn't find const_missing Brian Candler <b.candler@pobox.com> - 2011-04-21 16:26 -0500
  Re: class_eval doesn't find const_missing Andrew Berkeley <andrew.berkeley.is@googlemail.com> - 2011-04-22 14:43 -0500

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