2 Sep
2011
2 Sep
'11
12:49 p.m.
On 09/02/2011 12:04 PM, Fons Adriaensen wrote:
On Thu, Sep 01, 2011 at 03:54:03PM -0400, Paul Davis
wrote:
boost::function<void(void)> serves this purpose for me in jass. To
create and pass a functor that assigns a new auditor generator to the
one in the engine, and then tells it to play i do for example:
write_blocking_command(assign(engine_.auditor_gen, p));
write_blocking_command(boost::bind(&engine::play_auditor,
boost::ref(engine_))); assign() is just a utility template to make
creating functors that do assignments easier.. boost::bind is used to
make all passed functors 0-ary (e.g for binding member functions to
their instance or binding arguments to the functor.. and
write_blocking_command is just a utility function that disables the GUI
until the acknowledgement from the engine has come back to the GUI,, The
command ringbuffer is just a ringbuffer holding
boost::fucntion<void(void)> objects..
typedef ringbuffer<boost::function<void(void)> > command_ringbuffer;
Examples from here:
https://github.com/fps/jass/blob/master/main_window.h
https://github.com/fps/jass/blob/master/assign.h
https://github.com/fps/jass/blob/master/engine.h Regards, Flo
On Thu, Sep 1, 2011 at 2:37 PM, Fons
Adriaensen<fons(a)linuxaudio.org> wrote:
Yes, but
1. I find functor syntax extremely clumsy, involving the creation of
a specific derived functor class (from a template class) for each
one you need.
2. AFAIK (using the terminology of<http://www.newty.de/fpt/functor.html>,
you can't have a TSpecificFunctor member in the event class and
initialise it, it has to be a TSpecificFunctor*. Which in turn
means that at the sender side you either have instances of all
possibly required functor classes available and assign the
TSpecificFunctor* in the event from one of them, or you have to
use new() to allocate one. The former is extremely clumsy, and
the latter shouldn't be done in a RT context.
What I'm missing in C++ is a built-in 'functor' type that can
simply be assigned from any object::method, with the user being
responsible for the existence of the object and for supplying the
right arguments at the time the functor is called.
That's assuming that the event's virtual
execute() has access to
all it needs. In all cases I've encountered that is not the case:
the event triggers something in the context where it is received
and processing it requires access to that context's data.
It's a problem for which I don't know a clean C++ solution.
depending on
the exact type of thing you're talking about, isn't this
is place for closures, functors, etc. etc. ? Ciao,