On Saturday, 22 January 2022 at 18:00:58 UTC, vit wrote:
I want implement something like this:
...
Take by value and make a copy without forwarding:
```d
import std.typecons : Tuple;
import std.meta : allSatisfy;
enum bool isRcPtr(T) = is(T == RcPtr!U, U);
//@safe access to data of multiple ref counted objects:
public auto apply(alias fn, Args...)(Args args)
if (allSatisfy!(isRcPtr, Args)) {
Tuple!Args params = args; // borrow all
@property auto ref elm(alias param)()@trusted{
return param.get();
}
return fn(staticMap!(elm, args)); // staticMap over original
args tuple
}
```
Or make a helper function that takes by value and forward to that:
```d
template apply(alias fn)
{
private auto impl(Args...)(Args args)
{
@property auto ref elm(alias param)()@trusted{
return param.get();
}
return fn(staticMap!(elm, args));
}
auto apply(Args...)(auto ref Args args)
if (allSatisfy!(isRcPtr, Args))
{
import core.lifetime : forward;
return impl(forward!args); // impl takes by value -
RcPtrs passed by reference will be copied
}
}
```
