mapper.rb

class Mapper < BasicObject
  def initialize(enumerable)
    @enumerable = enumerable
  end

  def method_missing(*args, &block)
    @enumerable.map { |o| o.public_send(*args, &block) }
  end
end

module Enumerable
  def mapper
    Mapper.new(self)
  end
end

# Similar to .map(&:method) when using no arguments:
[2, -5, 7, -42].mapper.abs # => [2, 5, 7, 42]

# But it can also receive arguments:
%w(hello world).mapper.count('l') # => [2, 1]

# And even blocks!
[1..5, 6..10].mapper.select(&:even?)  # => [[2, 4], [6, 8, 10]]

# It can be used to do some weird stuff:
(1..4).mapper ** 2 # => [1, 4, 9, 16]
%w(Ruby is weird).mapper + '!' # => ["Ruby!", "is!", "weird!"]