New D technique - disable usage of "new" and "delete"

[Basile B.]

On Friday, 5 January 2018 at 20:45:20 UTC, jmh530 wrote:
> On Friday, 5 January 2018 at 19:44:38 UTC, Basile B. wrote:
>> [snip]
>> - Libraries that don't want their aggregates to reside on the 
>> GC heap can use this, with a mixin. (note: although the 
>> GCAllocator can still be used...)
>
> Cool.
>
> Not sure I'm following with your point with the mixin. A mixin 
> like below works fine, but it would be a little annoying to get 
> the constructors working. The only way I can think of is to 
> pass them as strings to the create function.
>
> import std.experimental.allocator;
> import std.experimental.allocator.mallocator;
>
> class Foo
> {
>     int a;
>     @disable new (size_t size){return null;}
>     @disable delete (void* p){}
> }
>
> string create(T, string name)()
> {
>     import std.conv : to;
>
>     return T.stringof ~ " " ~ name ~ " = make!" ~ T.stringof ~
>                                               
> "(Mallocator.instance);\n" ~
>         "scope(exit) dispose(Mallocator.instance, " ~ name ~ 
> ");";
> }
>
> void main()
> {
>     mixin(create!(Foo, "f"));
>     f.a = 1;
> }

Yeah, i didn't explain correctly the mixin thing.
The mixin would be used to disable "new" and "delete", e.g

     enum disableNewAndDelete = "@disable new (size_t size){return 
null;} @disable delete (void* p){}";

and then you mix it in the classes of the framework that doesn't 
want "new" and "delete" to be used:

     mixin(disableNewAndDelete);