From: "Christoffer Lernö" <lerno@...>
Date: 2006-02-19T23:18:26+09:00
Subject: Re: [/QUIZ] metakoans.rb (#67)

This was not my first solution. It wasn't until Timothy Goddard  
posted his benchmarking method I realized I ought to be supporting  
multiple variables for a single call. This wasn't needed for passing  
the koans, but I thought it would be neat to do.

Thanks for a fun quiz!

/Christoffer


def attribute(*definition, &block)
   raise "Name missing when creating attribute" unless  
definition.length > 0
   definition.each do |entry|
     if entry.respond_to?(:to_hash)
       entry.to_hash.each_pair { |key, value| insert_attribute(key,  
value, block) }
     else
       insert_attribute(entry, nil, block)
     end
   end
end

def insert_attribute(name, value, block)
   default_value = block ? "instance_eval(&block)" : "value"
   begin
     attr_writer name.to_s
     eval("define_method(:#{name}) { return @#{name} if defined? @# 
{name}; @#{name} = #{default_value}}")
     eval("define_method(:#{name}?) { self.#{name} != nil }") # this  
could also simply alias the getter and still pass.
   rescue SyntaxError
     raise "Illegal attribute name '#{name}'"
   end
end