From: Trans <transfire@...>
Date: 2007-01-18T22:12:59+09:00
Subject: Hash#open! / Hash#close!

hi--

have a look:

  class Hash

    def open!
      class << self
        @_were_public = public_instance_methods - ['close!']
        @_were_public.each { |m| private m }
        def method_missing(s,*a)
          if s.to_s[-1,1] == '='
            self[s] = a.first
          else
            return self[s]
          end
        end
      end
    end

    def close!
      class << self
        @_were_public.each { |m| public m }
        @_were_public = nil
        remove_method(:method_missing)
      end
    end

  end

usage:

  h = {a=>1, :sort_by=>2}
  h.a  #=> NoMethodError
  h.sort_by #=> LocalJumpError
  h.open!
  h.a  #=> 1
  h.sort_by #=> 2
  h.close!
  h.a  #=> NoMethodError
  h.sort_by #=> LocalJumpError

thoughts? improvements? useful? bad-news?

 T


ps. i came across an oddity while messing with this:

irb(main):019:0> q = {}
=> {}
irb(main):020:0> q.sort_by
=> []
irb(main):021:0> q[:a] = 1
=> 1
irb(main):022:0> q.sort_by
LocalJumpError: no block given
        from (irb):22:in `sort_by'
        from (irb):22
        from :0
ruby 1.8.4 on debian