From: "ara.t.howard" <ara.t.howard@...>
Date: 2008-09-05T01:21:12+09:00
Subject: Re: Request for Block local methods, and Proc syntax


On Sep 4, 2008, at 8:34 AM, Patrick Li wrote:

>
> but you still can't do something this:
>
> html do
>  @code = retrieveCode
> end
> puts @code <-- doesn't work, because this is a different @code than  
> the
> one you assigned to.
>
>

sure you can:

require 'rubygems'
require 'tagz'
include Tagz.globally


content =
   html_{
     body_{
      @code = 42
     }
   }

puts @code

puts content



cfp:~ > ruby a.rb
42
<html><body>42</body></html>


you just have to be clever about when methods are in effect - check  
out the tagz source for an example of this.


alternatively you can skin it this way pushing and popping methods on  
the object in question:


cfp:~ > cat a.rb

content =
   html do
     body do
       img do
         @code = 42
       end
     end
   end

y 'content' => content, '@code' => @code




BEGIN {
   module Html
     Methods = lambda do
       def body &block
         "<body>#{ block.call }</body>"
       end

       def img &block
         "<img>#{ block.call }</img>"
       end
     end

     def Methods.new
       Module.new do
         module_eval &Methods
         def self.delete!() instance_methods.each{|m| remove_method m}  
end
       end
     end

     def Methods.push object
       singleton_class_for(object) do
         include(( @html_methods = Methods.new )) unless @html_methods
       end
     end

     def Methods.pop object
       singleton_class_for(object) do
         @html_methods.delete!  if @html_methods
       end
     end

     def Methods.singleton_class_for object, &block
       singleton_class =
         class << object
           self
         end
       block ? singleton_class.module_eval(&block) : singleton_class
     end
   end

   def html &block
     Html::Methods.push self
     content = instance_eval(&block)
     "<html>#{ content }</html>"
   ensure
     Html::Methods.pop self
   end

   require 'yaml'
}




cfp:~ > ruby a.rb
---
"@code": 42
content: <html><body><img>42</img></body></html>



you'll have to try harder than that before proposing changes to the  
language ;-)

cheers


a @ http://codeforpeople.com/
--
we can deny everything, except that we have the possibility of being  
better. simply reflect on that.
h.h. the 14th dalai lama