Yielding a block to another block

ruby-talk
1

Hi all,

The mocking framework in rspec uses method_missing to capture all the
messages sent to it, comparing the message to a list of expected
messages. For various reasons I'm trying to rework this so that
instead of using method_missing, we define the expected message on the
mock on the fly.

For that to happen, setting expectations on the mock ends up invoking this:

      def define_expected_method(sym)
        (class << self; self; end).__send__(:define_method, sym,
lambda {|*args| message_received(sym, *args)})
      end

The Proc yields *args, which are then passed to message_received. How
can I get the Proc to yield a block that is passed in with the call to
:sym? I tried this:

lambda {|*args, &block| ....

but it throws an error. Any other ideas? Let me know if the question
is not clear.

Thanks,
David

2

David Chelimsky wrote:

Hi all,

The mocking framework in rspec uses method_missing to capture all the
messages sent to it, comparing the message to a list of expected
messages. For various reasons I'm trying to rework this so that
instead of using method_missing, we define the expected message on the
mock on the fly.

For that to happen, setting expectations on the mock ends up invoking
this:

      def define_expected_method(sym)
        (class << self; self; end).__send__(:define_method, sym,
lambda {|*args| message_received(sym, *args)})
      end

The Proc yields *args, which are then passed to message_received. How
can I get the Proc to yield a block that is passed in with the call to
:sym? I tried this:

lambda {|*args, &block| ....

but it throws an error. Any other ideas? Let me know if the question
is not clear.

You cannot currently do that with a block (1.9 and 2.0 will
allow &block arguments). In the meanwhile, you can #eval the
method into existence instead:

  def define_expected_method(sym)
    class << self; self; end.__send__ :class_eval, %{
      def #{sym}(*args, &block)
        message_received sym, *args, &block # ?
      end
    }
  end

···

Thanks,
David

--
Posted via http://www.ruby-forum.com/\.

3

Eero Saynatkari wrote:

David Chelimsky wrote:

Hi all,

The mocking framework in rspec uses method_missing to capture all the
messages sent to it, comparing the message to a list of expected
messages. For various reasons I'm trying to rework this so that
instead of using method_missing, we define the expected message on the
mock on the fly.

For that to happen, setting expectations on the mock ends up invoking
this:

      def define_expected_method(sym)
        (class << self; self; end).__send__(:define_method, sym,
lambda {|*args| message_received(sym, *args)})
      end

The Proc yields *args, which are then passed to message_received. How
can I get the Proc to yield a block that is passed in with the call to
:sym? I tried this:

lambda {|*args, &block| ....

but it throws an error. Any other ideas? Let me know if the question
is not clear.

You cannot currently do that with a block (1.9 and 2.0 will
allow &block arguments). In the meanwhile, you can #eval the
method into existence instead:

  def define_expected_method(sym)
    class << self; self; end.__send__ :class_eval, %{
      def #{sym}(*args, &block)
        message_received sym, *args, &block # ?
      end
    }
  end

  # One of these days.. *sigh*
  def define_expected_method(sym)
    class << self; self; end.__send__ :class_eval, %{
      def #{sym}(*args, &block)
        message_received :#{sym}, *args, &block # ?
      end
    }
  end

···

Thanks,
David

--
Posted via http://www.ruby-forum.com/\.

4

Thank you! Can I credit you when I commit this?

···

On 9/2/06, Eero Saynatkari <eero.saynatkari@kolumbus.fi> wrote:

Eero Saynatkari wrote:
> David Chelimsky wrote:
>> Hi all,
>>
>> The mocking framework in rspec uses method_missing to capture all the
>> messages sent to it, comparing the message to a list of expected
>> messages. For various reasons I'm trying to rework this so that
>> instead of using method_missing, we define the expected message on the
>> mock on the fly.
>>
>> For that to happen, setting expectations on the mock ends up invoking
>> this:
>>
>> def define_expected_method(sym)
>> (class << self; self; end).__send__(:define_method, sym,
>> lambda {|*args| message_received(sym, *args)})
>> end
>>
>> The Proc yields *args, which are then passed to message_received. How
>> can I get the Proc to yield a block that is passed in with the call to
>> :sym? I tried this:
>>
>> lambda {|*args, &block| ....
>>
>> but it throws an error. Any other ideas? Let me know if the question
>> is not clear.
>
> You cannot currently do that with a block (1.9 and 2.0 will
> allow &block arguments). In the meanwhile, you can #eval the
> method into existence instead:
>
> def define_expected_method(sym)
> class << self; self; end.__send__ :class_eval, %{
> def #{sym}(*args, &block)
> message_received sym, *args, &block # ?
> end
> }
> end

  # One of these days.. *sigh*
  def define_expected_method(sym)
    class << self; self; end.__send__ :class_eval, %{
      def #{sym}(*args, &block)
        message_received :#{sym}, *args, &block # ?
      end
    }
  end

>
>> Thanks,
>> David

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Posted via http://www.ruby-forum.com/\.

5

David Chelimsky wrote:

Thank you! Can I credit you when I commit this?

Certainly

···

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