Don пишет: > Weed wrote: >> Denis Koroskin пишет: >> >>>> 80490eb: 8d 85 6c fe ff ff lea -0x194(%ebp),%eax >>>> 80490f1: 50 push %eax >>>> 80490f2: 8d 85 2c fb ff ff lea -0x4d4(%ebp),%eax >>>> 80490f8: e8 67 ff ff ff *call 8049064* >>>> 80490fd: e8 62 ff ff ff *call 8049064* >>>> return c2.i; >>>> 8049102: 8b 85 cc fc ff ff mov -0x334(%ebp),%eax >>>> ... >>>> >>>> >>>> (in 80490f8 and 80490fd simply two calls successively) >>>> >>>> If structures and classes were same that excellent optimization in any >>>> case would turn out >>> If that's your use case, then your should seriosly reconsider using >>> struct instead of class for your objects. >> >> Classes always give such overhead if them to use in such quality. For >> example, classes basically cannot be used as any mathematical objects >> using overload of arithmetics. But also not only arithmetics, it it is >> simple as a good example. >> >>> Alternatively, you can use += >>> instead. >> >> Here yes, but if I add classes of different types? Then not to escape >> any more from creation of the temporary object in the heap. >> >>> Other than that, this is not a convincing argument. >>> >>> Reading many of your posts I came to a conclusion that you are >>> shortsighted and too crazy about performance. What you care about is a >>> premature optimization, which is a root of all the evil. You should >>> ensure that your programm is complete and correct, first and *then* >>> start doing profiling and optimizations. >> >> The program is already ready. It entirely consists of the various >> mathematics. Approximately %30 times of performance are spent for >> similar superfluous work. On C++ the program will work on %30 faster (I >> hope :)) and on D I am will turn out to do nothing with it. >> >> >>> Going back to the topic, dividing user types into two cathegories >>> (structs and classes) is considered modern and right. >> >> I do not accept such argument:) >> >>> Some languages >>> lack structs support at all (e.g. Java), but structs are too useful for >>> optimization and language interoperation to drop them in a systems >>> programming language. Some lack classes and try doing everything with >>> structs (C). D takes the best of both worlds. >> >> Probably I have not understood something, but I do not suggest to refuse >> structures in general. I suggest to allow to create classes on a stack >> as it is made in C++. That is actually to make structures and classes >> same, than they and are, for example, in C++. >> >> In the initial message I have shown that for perfomance important that >> the class could be transferred and on value. And it not artful premature >> optimisation - objects on value always so are transferred, all >> programmers know it and use when do not wish to allocate a place in a >> heap, that is usually always when the object will live in {}. >> >> Besides, a class in a stack it is normal - keyword addition "scope" for >> classes too speaks about it. >> >> Rigidly having divided classes and structures D deprives of the >> programmer of some possibilities which give it C++-like languages. I >> consider that such languages should give all possibilities which allows >> CPU but hiding concrete architecture, otherwise I would choose less >> difficult in use language. > > Use classes if you want polymorphism. Otherwise, use structs. It's a > clear distinction, which is not at all arbitrary -- there are > significant implications for the generated code.
And if polymorphism is necessary and such calculations are necessary as I have above described? To emulate polymorphism with the mixins? Or simply to reconcile to such obvious losses? I about that that division into classes and structures in language D automatically reduce perfomance of programs. Unlike languages where this division is not present (C++).