Block callbacks

proc_callback.rb

# encoding: utf-8
#
# Extract from:
# @link: http://www.mattsears.com/articles/2011/11/27/ruby-blocks-as-dynamic-callbacks
# @link: http://techscursion.com/2011/11/turning-callbacks-inside-out

class ProcCallback
  def initialize(callable, *args)
    @callable  = callable.to_s
    @arguments = args.dup
  end

  def method_missing(method_name, *args, &block)
    case method_name.to_s
    when @callable, "#{@callable}?"
      block_given? ? yield(*@arguments) : true
    else
      false
    end
  end

end

Proc.class_eval do
  def callback(callable, *args)
    call ProcCallback.new(callable, *args)
  end
end

def test(&block)
  n = rand(2)
  if n == 1
    block.callback :success
  else
    block.callback :failure, "FAIL"
  end
end

test do |on|
  on.success { $stdout.puts "SUCCESS!" }
  on.failure { |msg| $stdout.puts "#{msg}!" }
end