From: Joel VanderWerf <vjoel@...>
Date: 2006-06-10T03:37:29+09:00
Subject: Re: Why the lack of mixing-in support for Class methods?

ara.t.howard@noaa.gov wrote:
...
> plus, the first case is annoying.  if it weren't, people wouldn't be
> rolling
> their own shortcuts left and right - which is kind of what this thread is
> about.

Here's another shortcut, dunno how original it is. I don't like the
#import (or #include!) suggestions because they take control away from
the module. In most cases, the module will know best which (if any)
class methods to contribute.

class Module
  def included_class_methods(&bl)
    if bl
      included_class_methods_module.module_eval(&bl)
    else
      included_class_methods_module.instance_methods
    end
  end

  def included(cl)
    cl.extend included_class_methods_module
  end

  private
  def included_class_methods_module
    @included_class_methods_module ||= Module.new
  end
end

module M
  included_class_methods do
    def bar; "BAR"; end
  end
  def self.zap; "ZAP"; end
  def foo; "FOO"; end
end

class C
  include M

  p bar

  begin
    zap
  rescue
    puts "Can't call C.zap"
  end
end

p C.new.foo

p M.included_class_methods

__END__

Output:

"BAR"
Can't call C.zap
"FOO"
["bar"]


-- 
      vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407