module AwesomeMethodArray

def &(_other_ary)
  super.tap do |arr|
    arr.instance_variable_set(:@__awesome_methods__, instance_variable_get(:@__awesome_methods__))
  end
end

def -(_other_ary)
  super.tap do |arr|
    arr.instance_variable_set(:@__awesome_methods__, instance_variable_get(:@__awesome_methods__))
  end
end

def grep(pattern, &blk)
  #
  # The following looks rather insane and I've sent numerous hours trying
  # to figure it out. The problem is that if grep gets called with the
  # block, for example:
  #
  #    [].methods.grep(/(.+?)_by/) { $1.to_sym }
  #
  # ...then simple:
  #
  #    original_grep(pattern, &blk)
  #
  # doesn't set $1 within the grep block which causes nil.to_sym failure.
  # The workaround below has been tested with Ruby 1.8.7/Rails 2.3.8 and
  # Ruby 1.9.2/Rails 3.0.0. For more info see the following thread dating
  # back to 2003 when Ruby 1.8.0 was as fresh off the grill as Ruby 1.9.2
  # is in 2010 :-)
  #
  # http://www.justskins.com/forums/bug-when-rerouting-string-52852.html
  #
  # BTW, if you figure out a better way of intercepting Array#grep please
  # let me know: twitter.com/mid -- or just say hi so I know you've read
  # the comment :-)
  #
  arr = if blk
          super(pattern) do |match|
            #
            # The binding can only be used with Ruby-defined methods, therefore
            # we must rescue potential "ArgumentError: Can't create Binding from
            # C level Proc" error.
            #
            # For example, the following raises ArgumentError since #succ method
            # is defined in C.
            #
            # [ 0, 1, 2, 3, 4 ].grep(1..2, &:succ)
            #
            begin
              eval("%Q/#{match.to_s.gsub('/', '\/')}/ =~ #{pattern.inspect}", blk.binding)
            rescue StandardError
              ArgumentError
            end
            yield match
          end
        else
          super(pattern)
        end
  arr.instance_variable_set(:@__awesome_methods__, instance_variable_get(:@__awesome_methods__))
  arr.select! { |item| (item.is_a?(Symbol) || item.is_a?(String)) } # grep block might return crap.
  arr
end