On Fri, Jan 27, 2012 at 6:37 PM, Sven Barth <pascaldra...@googlemail.com> wrote: > Am 27.01.2012 17:46, schrieb Thaddy: >> On 27-1-2012 17:25, Marco van de Voort wrote: >>> In our previous episode, Kornel Kisielewicz said: (snip) > === > > This compiles! > > So there MUST be specific code in place in the Delphi compiler to allow the > assignment from ugendiamond2.TSpez2 to ugendiamond1.TSpez1 as those are > different definitions. Thus this can not be a bug, but must be an > intentional feature. Allowing this in FPC as well would be doable. > > Now regarding Kornel's problem: we could(!) change the way the compiler > works in non-Delphi modes to what is described in the documentation (by > adding the type symbol's name to the generic's name as well), but this will > mean that we would have to define how units in Delphi and non-Delphi modes > can interact here. After that the corresponding code in the compiler can be > implemented to ensure this.
What I still don't understand is the way the code is compiled in the diamond case. Let's assume that TGeneric in this example has a lot of code. So after compilation we have: ugendiamonddecl.ppu ugendiamond1.ppu ugendiamond2.ppu ugendiamonddecl.o ugendiamond1.o ugendiamond2.o As you stated, the ugendiamonddecl.ppu holds the tokens for generation of TGeneric, so the code is "kept" in ugendiamonddecl.ppu. What about the object files? The only reasonable general solution I see is that both ugendiamond1.o and ugendiamond2.o hold the generated code -- Delphi may do it otherwise because it may use different intermediate file formats (true?) In this case FPC's specialize could be the mode to be "smarter" requiring a explicit instantiation that at the same time shows in which object should the code be stored. It's kind of like the problem with the instantiation and template export in C++... Also, I'd be a big fan of extending the FPC version of templates in the direction allowing more powerful generic metaprogramming (without the broken C++ heritage), and I think that explicit instantiation would simplify that quite a lot. -- regards, Kornel Kisielewicz _______________________________________________ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-devel
