Hi Fredrik, I'm attaching the discussion during the formal review regarding the comparison operators. But before you dip into the reading, I'd like to say that my intension was to write STL compliant container nothing less or more and I'd like to stick with this. Jan Subject: RE: [boost] Formal Review: Circular Buffer Date: Tue, 9 Mar 2004 09:44:34 -0800 From: "Powell, Gary" <powellg@amazon.com> To: boost@lists.boost.org Shouldn't the comparison functions allow the types to differ? I mean don't they still lexigraphically compare as long as there is a comparison function F that a F b for each element exists circular_buffer<T, MyAlloc> x; circular_buffer<S, YourAlloc> y; bool b = x == y; for where the operator T == S is valid? And what does the allocator have to do with it? Therefore IMO, all of the comparison functions should change from template< typename T, typename Alloc> bool operator F ( circular_buffer<T, Alloc> &lhs, circular_buffer<T, Alloc> &rhs); to template< typename T1, typename Alloc1, typename T2, typename Alloc2> bool operator F ( circular_buffer<T1, Alloc1> &lhs, circular_buffer<T2, Alloc2> &rhs); Yours, -Gary- ----------------------------------------------- To: boost@lists.boost.org From: "Pavel Vozenilek" <pavel_vozenilek@hotmail.com> Date: Tue, 9 Mar 2004 20:52:29 +0100 Subject: [boost] Re: Formal Review: Circular Buffer Hmm, do you know a STL implementation/some container with this feature? It may be often bug to compare containers with different types. /Pavel ----------------------------------------------------- Subject: RE: [boost] Re: Formal Review: Circular Buffer Date: Tue, 9 Mar 2004 13:55:15 -0800 From: "Powell, Gary" <powellg@amazon.com> To: boost@lists.boost.org No, but just because the standard libraries scr*wed up is no reason to perpetuate the mistake. It's the rule of unexpected consequences. Is circular_buffer<int> x = { 1, 2, 3}; circular_buffer<short> y = { 1, 2 ,3}; x == y ?? or not? Sure looks like it should work. The VTL library does it IMO correctly, allowing that if there is an operation T1 F T2, then V1 F V2 compiles. Otherwise you just force the user to write what should be library code. --------------------------------------------- Send instant messages to your online friends http://uk.messenger.yahoo.com