closure_return_demo.rb

class ClosureReturnDemo
  def return_from_proc
    Proc.new do
      return true if true
    end.call
    puts "   OUT:"
  end

  def break_from_proc
    Proc.new do
      break true if true
    end.call
    puts "   OUT:"
  end

  def return_from_lambda
    lambda do
      return true if true
    end.call
    puts "   OUT:"
  end

  def break_from_lambda
    puts "   OUT:"
  end

  def spotcar
    yield
    puts "SC OUT:"
  ensure
    puts "SC2OUT:"
  end

  def return_from_block
    spotcar do
      return true if true
    end
    puts "   OUT:"
  end

  def break_from_block
    spotcar do
      break true if true
    end
    puts "   OUT:"
  end

  def return_from_lambda_as_block
    x = lambda do
      return true if true
    end

    spotcar(&x)
    puts "   OUT:"
  end

  def break_from_lambda_as_block
    x = lambda do
      break true if true
    end

    spotcar(&x)
    puts "   OUT:"
  end

  def return_from_proc_as_block
    x = Proc.new do
      return true if true
    end

    spotcar(&x)
    puts "   OUT:"
  end

  def break_from_proc_as_block
    x = Proc.new do
      break true if true
    end
    
    spotcar(&x)
    puts "   OUT:"
  end

  def execute
    %w(return_from_proc break_from_proc
       return_from_lambda break_from_lambda
       return_from_block break_from_block
       return_from_lambda_as_block break_from_lambda_as_block
       return_from_proc_as_block break_from_proc_as_block).each do |x|
      begin
        send x
        puts "   END: %s\n\n" % [x]
      rescue
        puts "  PROB: %s\n\n" % [$!.message]
      end
    end
  end
end

ClosureReturnDemo.new.execute

__END__
   END: return_from_proc

  PROB: break from proc-closure

   OUT:
   END: return_from_lambda

   OUT:
   END: break_from_lambda

SC2OUT:
   END: return_from_block

SC2OUT:
   OUT:
   END: break_from_block

SC2OUT:
   END: return_from_lambda_as_block

SC2OUT:
  PROB: break from proc-closure

SC2OUT:
   END: return_from_proc_as_block

SC2OUT:
  PROB: break from proc-closure