backporting features to D1

[Christopher Wright]

Frank Benoit wrote:
> Christopher Wright schrieb:
>> Jarrett Billingsley wrote:
>>> Then address the issues of stack vs. heap delegates.
>> That is not required for Tango to function properly with D2. It's a
>> performance optimization only. A significant one, but no more.
> 
> I disagree here.
> If you use lambdas for filters in inner loops, that is a main
> performance hit. It is more than just "optimization", it is a reason to
> change the design. It is a reason not to use D2. It is a D2 show-stopper.
> Even worse, no error message is showing you the problematic places, D2
> just makes your heap explode.
> 
> int findMyTypeXYZ( MyType[] a, int criteria ){
> 	int match = convCrit( criteria );
> 	return tango.core.Array.findIf( a, delegate bool(T e){ return e.attrib
> is match; });
> }
> 
> First this run without allocation, now it does allocate.
> Image how this behave if called very often :(
> And even worse, there is no way to manually delete the allocated stack
> frames. So there is no way around the GC runs.
> Finally I would end up in rewriting that code, not using a delegate
> based design. But IMHO this is one of the important D features.

Well, how much of a performance hit is it?

If the average application will run half as fast, then this is a 
significant issue that should be addressed soon. But it will not prevent 
me from using Tango with D2 in the interim.

If it's a 100x performance hit, then I wouldn't expect a port of Tango 
yet. But I suspect that it's more like a 10-15% performance hit at most. 
(I am talking about a typical application. I'm sure you could get a 
benchmark that runs much slower by choosing library calls that make 
extensive use of delegates and using those constantly.) I don't know; 
nobody has given any ballpark figures, much less benchmarks.

I'm going to try porting some of my code to D2/Tango. I'll post the results.