class EigenProc < Proc
  def initialize(&prc)
    super
    (class << self; self end).class_eval { define_method(:call,&prc); alias_method :[], :call }
  end
end
module Kernel; def sproc &blk; EigenProc.new &blk end end

if $0 == __FILE__
  # recursivity
  fib = sproc { |n| n<2 ? n : self[n-2]+self[n-1] }
  p (0..10).map{|i|fib[i]}

  # scope
  a = 'foo'
  sproc { |b| puts a+b }['bar']
end