Camping list - May 2007 - Module Madness

I''m wanted to make a "global" module that I could include in
my
application for some shared code between them.  I''ve been making
several camping apps and wanted them all to share a helper/partial
that contained the navigation.

I ran into a lot of difficulty when trying to include it, the primary
problem being "methodUndefined" errors.  I did finally get it to work,
but I''m not sure why.  Here''s the relevant bits:

my_app.rb
MyApp::Helpers
  include Global::Helpers
  def month_name
     ...helper code
  end
end

MyApp::Views
  def layout
    ...some markaby
    :navigation #throws an UndefinedMethod error if not a symbol
    ...some more markaby
  end
end

global.rb
module Global
  module Helpers
    def navigation
      ...what i need
    end
  end
end

If I list the instance methods in irb, both "navigation" and
"month_name" shows up.  However, I have to use use :navigation as a
symbol in my view as opposed to just using month_name for the other.
Both are defined as instance methods.

What gives with the symbol usage?

I was wrong.  A symbol didn''t work, it just didn''t throw an
error.
>From the code below, can anyone see why I wouldn''t be able to
namespace a Global::Helpers module and include it in MyApp::Helpers
and have the methods available?

This seems to be the way that Camping::BasicAuth works, are
views/helpers different?

---------- Forwarded message ----------
From: Joshua Schairbaum <joshua.schairbaum at gmail.com>
Date: May 7, 2007 2:31 PM
Subject: Module Madness
To: camping-list at rubyforge.org


I''m wanted to make a "global" module that I could include in
my
application for some shared code between them.  I''ve been making
several camping apps and wanted them all to share a helper/partial
that contained the navigation.

I ran into a lot of difficulty when trying to include it, the primary
problem being "methodUndefined" errors.  I did finally get it to work,
but I''m not sure why.  Here''s the relevant bits:

my_app.rb
MyApp::Helpers
  include Global::Helpers
  def month_name
     ...helper code
  end
end

MyApp::Views
  def layout
    ...some markaby
    :navigation #throws an UndefinedMethod error if not a symbol
    ...some more markaby
  end
end

global.rb
module Global
  module Helpers
    def navigation
      ...what i need
    end
  end
end

If I list the instance methods in irb, both "navigation" and
"month_name" shows up.  However, I have to use use :navigation as a
symbol in my view as opposed to just using month_name for the other.
Both are defined as instance methods.

What gives with the symbol usage?

On Tue, May 08, 2007 at 12:42:55PM -0400, Joshua Schairbaum
wrote:
> I was wrong.  A symbol didn''t work, it just didn''t throw
an error.
> >From the code below, can anyone see why I wouldn''t be able to
> namespace a Global::Helpers module and include it in MyApp::Helpers
> and have the methods available?
> 
> This seems to be the way that Camping::BasicAuth works, are
> views/helpers different?
As far as I know helpers are methods in the MyApp module. I don''t
know if Camping uses or ever has used MyApp::Helpers.
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On May 7, 2007, at 1:31 PM, Joshua Schairbaum wrote:
> I''m wanted to make a "global" module that I could
include in my
> application for some shared code between them.  I''ve been making
> several camping apps and wanted them all to share a helper/partial
> that contained the navigation.
I think the root of the "problem" is the way the app modules are  
loaded into the Markaby rendering context:

   module Views; include Controllers, Helpers end
   class Mab < Markaby::Builder
       include Views
       def tag!(*g,&b)
           h=g[-1]
           [:href,:action,:src].each{|a|(h[a]=self/h[a])rescue 0}
           super
       end
   end

Here''s a slightly unnerving hack which seems to solve the problem.   
You pass it the base module (or symbol of) your Camping app and one  
or more shared helper modules, and it''ll inject them into your  
Camping app.  (Obviously the symbol parameters won''t work if you have  
nested modules...you''ll have to pass in the module constant  
instead...the symbols are just syntactic sugar to echo Camping.goes().)

class TentSteak
   def self.bootstrap(mod_or_sym, *appmods)
     @@rootmod = mod_or_sym.instance_of?(Module) ? mod_or_sym :  
const_get(mod_or_sym.to_s)
     inject appmods
   end
   def self.inject(*mod_or_syms)
     @@rootmod.module_eval "class Mab < Markaby::Builder; include # 
{mod_or_syms.join('', '')}; end"
   end
   def self.view_method_defined?(meth)
     @@rootmod::Mab.method_defined?(meth)
   end
end

Usage is like this:

   Camping.goes :MyApp
   TentSteak.bootstrap :MyApp, :MyHelperModule, :MyOtherHelpers

I''d love to hear if there''s a better way to do this injection.
Seems
pretty hacky.  Incidentally, TentSteak is a Camping helper library  
I''ve been working on recently.  I''ll upload it to rubyforge as
soon
as I get the ugly corners chiseled off and properly tested/ 
documented....

John

-- 
"The Internet is not something you just dump something
on.  It''s not a big truck.  It''s a series of tubes."
  --Senator Ted Stevens, R-AK

John R. Sheets
http://bark.metacasa.net



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