在 Wed, 01 Apr 2009 18:36:56 +0800，Christian Kamm
<[email protected]> 写道:
Walter Bright Wrote:
Instead, you can do this:
class inherit : base
{
ctor(int i) { }
ctor() { super(); }
}
Yes, but it gets uncomfortable when you want to forward more
constructors:
class base {
ctor(int never, MyTemplate!(float, 3, "abcd") ending, char[] parameter
= "abcd", int list = 3) {}
ctor(float including, int defaults = 3) {}
}
class derived : base {
ctor(int never, MyTemplate!(float, 3, "abcd") ending, char[] parameter
= "abcd", int list = 3)
{ super(never, ending, parameter, list); }
ctor(float including, int defaults = 3)
{ super(including, defaults); }
}
plus you have to replicate default values and make sure you update all
derived classes when changing the base constructors. I.e. the same
arguments that explain why you can use alias to bring base class member
functions into the overload set apply to the constructor. Also,
sometimes the base class constructors are unknown:
class C(T) : T { this(?) { super(?); }
I guess these issues could also be solved using a mixin if there was a
way to enumerate constructors at compile time, but there's another
advantage to renaming 'this' to a non-keyword name: you allow getting
its address and using it as a template alias parameter.
Yeah, all the merits of ctor just outweigh its demerits. The only demerit
of it is taking "ctor" to join the keyword list, However it also bans
people from using ctor as a var( it might be positive! )
