Module#set

ruby-talk
1

Wonder what other's think of this as a general purpose class method.
It comes from Sinatra, but I have been seeing it's like used in other
places too.

   class Module
      # Sets an option to the given value. If the value is a proc,
      # the proc will be called every time the option is accessed.
      def set(option, value=self, &block)
        raise ArgumentError if block && value != self
        value = block if block
        if value.kind_of?(Proc)
          metadef(option, &value)
          metadef("#{option}?") { !!__send__(option) }
          metadef("#{option}=") { |val| set(option, Proc.new{val}) }
        elsif value == self && option.respond_to?(:to_hash)
          option.to_hash.each { |k,v| set(k, v) }
        elsif respond_to?("#{option}=")
          __send__ "#{option}=", value
        else
          set option, Proc.new{value}
        end
        self
      end
   end

Example:

  class X
    set :x, 10
  end

  X.x #=> 10
  X.x = 5
  X.x #=> 5