clear()

[Yigal Chripun]

On 09/10/2009 19:53, Max Samukha wrote:
> On Fri, 09 Oct 2009 11:40:43 -0500, Andrei Alexandrescu
> <SeeWebsiteForEmail at erdani.org>  wrote:
>
>> I'm talking with Sean and Walter about taking the first step towards
>> eliminating delete: defining function clear() that clears the state of
>> an object. Let me know of what you think.
>>
>> One problem I encountered is that I can't distinguish between a default
>> constructor that doesn't need to exist, and one that was disabled
>> because of other constructors. Consider:
>>
>> class A {}
>> class B { this(int) {} }
>>
>> You can evaluate "new A" but not "new B". So it's legit to create
>> objects of type A all default-initialized. But the pointer to
>> constructor stored in A.classinfo is null, same as B.
>>
>> Any ideas?
>>
>
> The notion of default constructor is not quite clear.
>
> class A
> {
>    this(int a = 22) {}
> }
>
> Should A be considered as having a default constructor?
>
> class B
> {
>    this(int) {}
> }
>
> Should passing int.init to B's constructor be considered default
> construction? If yes, we could recreate B using the init value. But
> then:
>
> class C
> {
>    this(int a) {}
>    this(int a, int b) {}
> }
>
> Which constructor to call? The one with fewer parameters? What if
> there are overloaded constructors with identical number of parameters?
> Should we explicitly mark one of the constructors as default?

I agree. classinfo.defaultConstructor should be replaced by an array of 
all the constructors. Only when the array is empty you assume the 
existence of the default compiler generated constructor.