look_at.rb

class LookAt
  DEFAULTS = {:output => true}
  def initialize(thing, options = {})
    @thing = thing
    @options = DEFAULTS.merge(options)

    meths = case @thing.class
    when Class, Module
      (@thing.methods.sort - Class.methods)
    else
      (@thing.methods.sort - Object.instance_methods)
    end

    if @options[:output]
      puts "-- #{@thing.inspect} is a #{@thing.class} --"
      puts meths.inspect
    end
  end
end

def self.look_at(thing, options = {})
  LookAt.new(thing, options)
end

class Object
  def look_at(options = {})
    LookAt.new(self, options)
  end
end

if __FILE__ == $0
  array  = %w{Mister Array}
  string = 'Mr. String'
  hash   = {:mister => 'hash'}

  puts '*** Global Method ***'
  look_at(array)
  look_at(string)
  look_at(hash)

  puts "\n*** Instance Method ***"
  array.look_at
  string.look_at
  hash.look_at
end