std.container.RedBlackTree versus C++ std::set

[monarch_dodra]

On Wednesday, 13 February 2013 at 23:22:03 UTC, Ivan Kazmenko 
wrote:
> Hi!
> -----
> Ivan Kazmenko.

Keep in mind that C++ and D have very different philosophies 
regarding copy construction.

C++ has "strong ownership", so for example, whenever you copy a 
string/vector, or pass it by value, the whole damn thing has to 
be completely duplicated. It's so expansive that C++ has gone out 
of its way to use pass-by-reference semantics, as well (now) 
RValue references.

D, on the other hand (being GC), has a "shallow ownership" 
philosopy: Basically, when you make a copy, nothing happens, 
appart from the binary copy of the object. You want to pass a 
string by value? that's 8 bytes of data. Period. The *most* 
complex CC I have *ever* seen in D merely increments a reference 
counter. That's it. 90% (99%?) of the time, there isn't even a 
postblit implemented. Because of this, D has embraced pass by 
value.

Not to mention, if you are using classes, those are already 
pointer types. Why pass them by ref?

--------

The conclusion is that the comparison is not fair: D's pass by 
value is not *very* different from C++'s pass by ref (in amount 
of data copied).

If you *do* want a fair-er comparison, then I'd suggest you 
implement a ".dup" on your object, and see how many times THAT 
gets called. Guess what: 0.

I'm not saying D's approach is perfect, just that D's library is 
optimized for D-like types.

Just the same, a lot the stl is not properlly optimized for 
little POD types, as they get passed around by ref, when their 
actual size is the same as the pointer referencing them...