From: Lionel Thiry <lthiryidontwantspams@...>
Date: 2006-02-08T08:48:21+09:00
Subject: Re: Meta-Meta-Programming

http://www.rcrchive.net/rcr/show/321

Erik Veenstra a �crit :
> 
>      1   class Module
>      2     def just_wrap(method_name)
>      3       wrap_method(method_name) do |org_method, args, block|
>      4         org_method.call(*args, &block)
>      5       end
>      6     end
>      7   end
>      8   class Foo
>      9     def bar(x, y, z)
>     10       p [x, y, z]
>     11     end
>     12     just_wrap :bar   # !!!!!
>     13   end
>     14   Foo.new.bar("a", "b", "c") # ===> ["a", "b", "c"]
> 

class Foo
  def bar(x, y, z)
    p [x, y, z]
  end
end

cut JustWrap < Foo
  def bar
    super
  end
end

> 
>      1   class Module
>      2     def big_arguments(method_name)
>      3       wrap_method(method_name) do |org_method, args, block|
>      4         args = args.collect{|x| x.to_s.upcase}
>      5         org_method.call(*args, &block)
>      6       end
>      7     end
>      8   end
>      9   class Foo
>     10     def bar(x, y, z)
>     11       [x, y, z]
>     12     end
>     13     big_arguments :bar
>     14   end
>     15   Foo.new.bar("a", "b", "c") # ===> ["A", "B", "C"]
> 

class Foo
  def bar(x, y, z)
    p [x, y, z]
  end
end

cut BigArguments < Foo
  def bar(*args)
    super(*args.collect{|x| x.to_s.upcase})
  end
end

> 
>      1  class Module
>      2    def find_nil(method_name)
>      3      wrap_method(method_name) do |org_method, args, block|
>      4        if args.include?(nil)
>      5          $stderr.puts "Found a nil when called from #{caller[1..-1].inspect}."
>      6        end
>      7        org_method.call(*args, &block)
>      8      end
>      9    end
>     10  end
>     11  class Foo
>     12    def bar(x, y, z)
>     13    end
>     14    find_nil :bar
>     15  end
>     16  Foo.new.bar("a", "b", "c") # ===>
>     17  Foo.new.bar("a", "b", nil) # ===> Found a nil when called from from ["test.rb:17"].
>     18  Foo.new.bar("a", "b", "c") # ===>
> 

class Foo
  def bar(x, y, z)
  end
end

cut FindNil < Foo
 def bar(*args)
  if args.include?(nil)
   $stderr.puts "Found a nil when called from #{caller[1..-1].inspect}."
  end
  super(*args)
 end
end

-- 
Lionel Thiry

Personal web site: http://users.skynet.be/lthiry/