On 12/9/2012 2:10 PM, Jonathan M Davis wrote:
You're basically suggesting that we disallow any idiom which requires that structs be deep copied, and I think that that's bad policy. It's one thing to encourage programmers to not write such structs and to use other idioms like COW or reference counting. It's another thing entirely to disallow them. It's one of C++'s prime tenets to try and not force the programmer to program in a certain way or in a certain paradigm, and I think that D should do the same.
We already disallow several C++ idioms - like multiple inheritance, using a type as both a value and a reference type, and head const. We believe that these are bad design patterns, despite them being used often in C++.
I do not dispute that deep copy is commonly used in C++. I challenge the idea that it is a good design pattern, i.e. better than using copy-on-write.
