dcollections 1.0 and 2.0a beta released

[Steven Schveighoffer]

Michel Fortin Wrote:

> On 2010-05-20 09:22:27 -0400, Steven Schveighoffer <schveiguy at yahoo.com> said:
> 
> > Michel Fortin Wrote:
> > 
> >> On 2010-05-20 06:34:42 -0400, Steven Schveighoffer <schveiguy at yahoo.com> said:
> >> 
> >>> I understand these points, but I'm already using interfaces to copy
> >>> data between containers.  I don't have to, I could have used generic
> >>> code, but this way, only one function is instantiated to copy data from
> >>> all the other containers.  The problem with using generic code is that
> >>> the compiler will needlessly duplicate functions that are identical.
> >> 
> >> One question. Have you calculated the speed difference between using an
> >> interface and using generic code? Surely going through all those
> >> virtual calls slows things down a lot.
> >> 
> >> I do like interfaces in principle, but I fear it'll make things much
> >> slower when people implement things in term of interfaces. That's why
> >> I'm not sure it's a good idea to offer container interfaces in the
> >> standard library.
> > 
> > It's not that much slower.  You get a much higher speedup when things 
> > can be inlined than virtual vs. non-virtual.
> 
> Yes, but that was part of the equation: a call to a template function 
> can be inlined, not a virtual call (most of the time).

So if you want inlining, use the actual type, nothing is stopping you.  Well, except the non-final functions, I have to fix that.

> > One thing I just thought of -- in dcollections, similar types can be 
> > compared to one another.  For example, you can check to see if a 
> > HashSet is equal to a TreeSet.  But that would not be possible without 
> > interfaces.
> 
> I'm not sure of what you're saying here. Are you saying it can be done 
> with an interface but not with a template type? Why can't this work:

Because comparing two objects for equality now calls this function:

bool opEquals(Object obj1, Object obj2)

Which is defined in object_.d in the runtime.  No compile-time anything is allowed.

-Steve