Re: [boost] [signals2] Uncombined signal

Le 18 avr. 2013 à 17:24, Frank Mori Hess a écrit :

On Wed, Apr 10, 2013 at 7:44 PM, Ivan Le Lann wrote:

...

Hi,

I have a project where I use boost::signals2 in the spirit of the "Signal Return Values (Advanced)" section of the tutorial. That is, I have signals roughly equivalent to :

boost::signals2::signal sig; // slots produce values accumulated by the combiner

Problem comes when I want multiple combiners on the same slots. Especially combiners of different types : You need to duplicate signals, and you need your connection setup code to know about used combiners.

IMHO, having a basic signal class with no combiner makes sense. Attached is a POC patch to version 1.50, to add to boost::signals2::signal the method :

slot_call_range all (BOOST_SIGNALS2_SIGNATURE_FULL_ARGS(BOOST_SIGNALS2_NUM_ARGS)) const

(in boost/signals2/detail/signal_template.hpp)

From there, I think one could use any algorithm/accumulator directly on the signal.all() result. Implementation left aside, any feedback on this ?

I'm not really grasping your use case/motivation for this. Could you just use a combiner that returns a vector of all the individual return values?

I did that. Main problem it that it is not lazy. Not all algorithms dereference all iterators. Now I understand I am abusing signals2::signal here. And I really don't think this class should expose its slots as my dummy patch does. I do think however that the "connection container with slot call iterator" mecanism used in signals2 is useful enough to be publicly exposed. Regards, Ivan