new_map.rb

#!/usr/bin/env ruby1.9
# Extends Array#map to take symbols, without having to use & on them.

# I can't find any way to define this in Enumerable and then have it
# automatically get picked up by Array et al. Even when I defined this in a
# module (Enumerable or another) and then include it into Array, it doesn't
# seem to recognize the new method.
class Array
  alias old_map map
  def map(arg=nil)
    puts "Calling new map"
    if arg.is_a? Symbol
      puts "Arg is a symbol"
      old_map { |i| arg.to_proc.call i}
    else
      if block_given?
        old_map { |i| yield i }
      else
        old_map(arg)
      end
    end
  end
end

ary = %W[foo\n bar\n baz\n]
p ary.map(&:chomp)
p ary.map(:chomp)