David Abrahams <dave@boost-consulting.com> writes: | Brian McNamara <lorgon@cc.gatech.edu> writes: | | > Apologies ahead of time if I am putting words in anyone's mouth. | > | > I think Dave wants to imply that the class T in his example is not | > allowed to have a member named U according to Gaby's proposed rule. | | That's what I thought he meant. But then, your remark about "would be horrible for generic program" is, ahem, puzzling. You still did not explain why. | > But this isn't how the rule would work; the way I see it, _these_: | > | > struct Base { typedef int U; }; | > | > template <class U> | > struct Derived : Base { }; // illegal | > | > struct Derived2 : Base { | > template <class U> | > void f(U u) {} // illegal | > }; | > | > would be illegal ("the name U already has another meaning; choose | > another name for your template parameter"), whereas _these_: | > | > struct Base { typedef int U; }; | > | > template <class B, class U> | > struct Derived : B { }; | > /* ... Derived<Base> ... */ | > | > template <class B> | > struct Derived2 : B { | > template <class U> | > void f(U u) {} | > }; | > /* ... Derived2<Base> ... */ | > | > are both fine, since Base's "U" is hidden by virtue of being a dependent | > name. There is still an issue of what happens if one of these last two | > classes issues a "using B::U" in its body; presumably then "U" ought to | > become outlawed as a valid template parameter name. | > | > Just my two cents here... | | OK, I think I understand now. I think it's a bizarre and inconsistent | rule. What is bizarre and inconsistent about it and is not with the other alternatives you care to name? This question is not rhetorical. When you register strong opinons about a technical issue or throw in the air fashionable words like "generic programming", the least that could be expected is that you provide technical explanation. | Shall we outlaw: | | struct Base { static int x; }; | | struct Derived : Base { | void f(int x) {} // Horrors! we're masking a base class member! If you happen to pause a second and have look at the issue at hand, I'm confident that you'll see the difference between the case we're discussing and your example. | }; | | Sorry for the sarcasm; And, I'm pretty sure you know sarcasm is not appropriate for tehcnical discussions. -- Gaby