[request] Use delegates for callbacks

[GoogleCodeExporter]

While interface objects do work, I suggest using something like <a
href="http://www.codeproject.com/KB/cpp/FastDelegate.aspx">FastDelegate</a>
as it would allow more flexibility when implementing callbacks and reduce
the virtual function call overhead.  Delegates would have the advantage of
allowing free functions, static methods, non-virtual methods, and virtual
methods with arbitrary names so long as they match the function signature.
 Choice is good.  :)

(I use FastDelegate extensively, so I could implement a demonstration
version without too much trouble.)

Original issue reported on code.google.com by kennethdmiller3 on 31 Aug 2009 at 2:50

[GoogleCodeExporter]

I wasn't sure if HTML would work, and it clearly didn't.  Anyway, the URL is
http://www.codeproject.com/KB/cpp/FastDelegate.aspx

Original comment by kennethdmiller3 on 31 Aug 2009 at 2:52

[GoogleCodeExporter]

FastDelegate requires non-standard C++ as well as compiler specific 
implementations.
 Too much work for little gain.  boost::function style delegates would work, but
don't provide any performance advantages (only trade offs).

Original comment by j.nick.terry@gmail.com on 31 Aug 2009 at 8:35

[GoogleCodeExporter]

While FastDelegate is indeed nonstandard, it's widely supported by modern 
compilers.
 There's another one
(http://www.codeproject.com/KB/cpp/ImpossiblyFastCppDelegate.aspx) that's
standards-compliant but less-widely supported (ironically).  There's always a
possibility that the iPhone or Nintendo DS platforms might have issues, but 
their
compilers seem decent enough.  (Ultimately, a delegate is a simple thing: a 
"this"
pointer and a function address.  There's only so many ways to construct a 
virtual
function or a pointer to member...)

Original comment by kennethdmiller3 on 31 Aug 2009 at 9:26

[GoogleCodeExporter]

I've made use of FastDelegate on the DS in both ARM and THUMB modes (haven't 
tested
it using the home-brew environment though)

Original comment by the.eter...@gmail.com on 2 Sep 2009 at 10:31

[GoogleCodeExporter]

You can essentially implement your own delegates already.

Original comment by erinca...@gmail.com on 19 Sep 2009 at 8:15

• Changed state: WontFix

[GoogleCodeExporter]

True, though it isn't as efficient because it requires a third layer of 
indirection
(virtual function table, virtual function, and target method).  :)

Original comment by kennethdmiller3 on 19 Sep 2009 at 2:15