D idioms list

[ketmar via Digitalmars-d-announce]

On Thu, 08 Jan 2015 22:25:11 +0100
Artur Skawina via Digitalmars-d-announce
<digitalmars-d-announce at puremagic.com> wrote:

> On 01/08/15 21:23, ketmar via Digitalmars-d-announce wrote:
> > i'm not sure, but maybe it worth renaming "struct inheritance" to
> > "extending a struct"? or even something completely different. what it
> > does is actually extending/augmenting the struct, but not
> > OO-inheritance, as one cannot pass "augmented" struct to the function
> > which expects original struct. at least without hackery.
> 
> 'alias this' is just the D syntax for implicit conversions.
> The feature /is/ crippled, but there's no need for "hackery";
> at least not for simple things like that.
> 
>    struct A { int a; }
>    struct B { A a; alias a this; string b; }
> 
>    int f(A a) { return a.a+1; }
>    int g(ref A a) { return a.a+1; }
>    ref A h(ref A a) { return a; }
> 
>    int main() {
>       B b;
>       return f(b)+g(b)+h(b).a;
>    }
> 
> artur
mea culpa. i completely forgot about that feature of `alias this`, and
was pretty sure that the code above is invalid. i never bothered to
really check it. sorry.
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