From: "Michael T. Richter" Date: 2008-05-21T11:02:42+09:00 Subject: 13 lines of confusion --=-1+davn9fuSAJzrwdlHDP Content-Type: multipart/alternative; boundary="=-R3fCLSE8hpPTaKGi5Wqj" --=-R3fCLSE8hpPTaKGi5Wqj Content-Type: text/plain Content-Transfer-Encoding: quoted-printable I can't for the life of me figure out why the following code makes Ruby puke when I try to execute it: module Rlang module Error class RlangException < Exception ; end end module Utility def e8(value) ; [value].pack('C') ; end end module External include Rlang::Error include Rlang::Utility TAG_CACHED_ATOM =3D e8(67) end end The precise error I get is "junk.rb:11: undefined method `e8' for Rlang::External:Module (NoMethodError)" which is the line with "TAG_CACHED_ATOM =3D ..." in it. I've tried the following changes with the following results: 1. Completely specify e8 by using "Rlang::Utility.e8" or "Rlang::Utility::e8". This produces no change to the message whatsoever. 2. Renaming bits and pieces under the assumption that I've got a naming clash with something deep. This only changes the name of the method it claims to not be able to find. 3. Moving the definition of e8 to be in the External module. This is where brain damage sets in as the message doesn't change in the slightest. (I am well and truly baffled by this stage.) 4. Moving the definition of e8 to be in the Rlang module. This results in, you guessed it!, no change to the message at all. 5. Moving the definition of e8 to be outside of any module at all. This results in ... it works. #5 is a solution but it is a truly suboptimal one in my opinion. I do not want to clutter up the global namespace of my clients with cryptic little utility functions (in the real code there's about a dozen of these). So while I could live with #5, I would rather not if there was a better way to do this. Something deep about Ruby's module system is eluding me here, I think, and I'd rather understand it than just cover it over and inconvenience my clients' coding in the process. --=20 Michael T. Richter (GoogleTalk: ttmrichter@gmail.com) The most exciting phrase to hear in science - the one that heralds new discoveries - is not "Eureka!" but "That's funny..." (Isaac Asimov) --=-R3fCLSE8hpPTaKGi5Wqj Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable I can't for the life of me figure out why the following code makes Ruby puk= e when I try to execute it:

module Rlang
  module Error
    class RlangException < Exception ; end
  end
  module Utility
    def e8(value) ; [value].pack('C') ; end
  end
  module External
    include Rlang::Error
    include Rlang::Utility
    TAG_CACHED_ATOM =3D e8(67)
  end
end

The precise error I get is "junk.rb:11: undefined method `e8' for = Rlang::External:Module (NoMethodError)" which is the line with &q= uot;TAG_CACHED_ATOM =3D ..." in it. I've tried the foll= owing changes with the following results:

Completely specify e8 by using "Rlang::Util= ity.e8" or "Rlang::Utility::e8". This produces no chan= ge to the message whatsoever.
Renaming bits and pieces under the assumption th= at I've got a naming clash with something deep. This only changes the= name of the method it claims to not be able to find.
Moving the definition of e8 to be in the Externa= l module. This is where brain damage sets in as the message doesn'= t change in the slightest. (I am well and truly baffled by this s= tage.)
Moving the definition of e8 to be in the Rlang m= odule. This results in, you guessed it!, no change to the message at = all.
Moving the definition of e8 to be outside of any= module at all. This results in ... it works.

#5 is a solution but it is a truly suboptimal one in my opinion. I do= not want to clutter up the global namespace of my clients with cryptic lit= tle utility functions (in the real code there's about a dozen of these).&nb= sp; So while I could live with #5, I would rather not if there was a= better way to do this. Something deep about Ruby's module system is = eluding me here, I think, and I'd rather understand it than just cover it o= ver and inconvenience my clients' coding in the process.

--
Michael T. Richter <ttmri= chter@gmail.com> (GoogleTalk: ttmrichter@gmail.com)
The most exciting phrase to hear in science - the one that heralds new d= iscoveries - is not "Eureka!" but "That's funny..." (Is= aac Asimov)

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