On 05/10/15 13:39, Marc Schütz wrote:
On Monday, 5 October 2015 at 09:25:30 UTC, Shachar Shemesh wrote:What's more, init is used even if you @disable this(). The following compile and does what you'd expect (but not what you want): struct S { int d;@disable this(); this( int d ) { this.d = d; } } ... S d = S.init;I don't understand this. How is that not what you want, considering that you explicitly told it to use the init value?
One of the basics of C++ is that, if you construct the type correctly, then the user of the type cannot use it in a way that will cause inconsistencies. Such a use will not compile.
The above shows that you cannot construct such a type in D. The language simply does not allow you to cancel a certain feature of the type in which you are uninterested.
Please bear in mind that the init might not be called directly. Programmer A defines a type that should never be uninitialized (i.e. - needs a constructor). Programmer B places an instance of that type inside a containing struct. Programmer C uses that containing struct's init. Such a problem is not easy to catch, even if programmers A, B and C are the same person.
Shachar
