Symbol#to_procに引数を指定できるようにしてみる ref: http://qiita.com/closer/items/9e162994583b0c56435d

file0.txt

class Symbol
  def to_proc(*args)
    -> receiver { receiver.send(self, *args) }
  end
  alias_method :[], :to_proc
end

file1.txt

puts (0..5).map(&:*[10])

file2.txt

[1, 10, 100].each do |number|

  puts "#{number} is"

  case number
  when :<[5]   then puts "less than 5."
  when :<[50]  then puts "less than 50."
  when :<[500] then puts "less than 500."
  end

  case number
  when :>[50] then puts "more than 50."
  when :>[5]  then puts "more than 5."
  when :>[0]  then puts "more than 0."
  end

end

file3.txt

module Kernel
  def less(boundary)
    :<[boundary]
  end

  def more(boundary)
    :>[boundary]
  end
end

[1, 10, 100].each do |number|

  puts "#{number} is"

  case number
  when less(5)   then puts "less than 5."
  when less(50)  then puts "less than 50."
  when less(500) then puts "less than 500."
  end

  case number
  when more(50) then puts "more than 50."
  when more(5)  then puts "more than 5."
  when more(0)  then puts "more than 0."
  end

end