class String
  # Evaluates a String as a Proc.
  #
  #   require 'facet/string/to_proc'
  #
  #   xyp = "|x,y| x + y".to_proc
  #   xyp.class      #=> Proc
  #   xyp.call(1,2)  #=> 3
  #
  #--
  # Note: Sure would be nice if this could
  # grab the caller's context!
  #++
  def to_proc(context=nil)
    if context
      if context.kind_of?(Binding) or context.kind_of?(Proc)
        Kernel.eval "proc { #{self} }", context
      else context
        context.instance_eval "proc { #{self} }"
      end
    else
      Kernel.eval "proc { #{self} }"
    end
  end
end