Re: How to define variadic delegate with a ref/out argument?

[pham via Digitalmars-d-learn]

On Friday, 17 November 2017 at 06:21:50 UTC, Jerry A. wrote:

On Friday, 17 November 2017 at 05:08:23 UTC, pham wrote:

struct DelegateList(Args...)
{
public:
alias DelegateHandler = void delegate(Args args) nothrow;

DelegateHandler[] items;

void opCall(Args args) nothrow
{
foreach (i; items)
i(args);
}
}

DelegateList!(string, int) list; // Compile OK so far
DelegateList!(string, int*) list2; // Compile OK so far
DelegateList!(string, ref int) list3; // Compile error -> How 
to make it work?


Thanks
Pham


The only way I know of is using  a template which behaves like 
a reference.
Which can be done with nullableRef I suppose. Haven't actually 
tried it.


import std.typecons : NullableRef, nullableRef;

DelegateList!(NullableRef!int)(nullableRef(some_int));


nullableRef is same as passing pointer. Using "ref" is stronger 
guarantee that the var is never be passed as null.


variadic parameter passed by "ref" should be supported

Thanks.
Pham

Re: How to define variadic delegate with a ref/out argument?

[Jerry A. via Digitalmars-d-learn]

On Friday, 17 November 2017 at 05:08:23 UTC, pham wrote:

struct DelegateList(Args...)
{
public:
alias DelegateHandler = void delegate(Args args) nothrow;

DelegateHandler[] items;

void opCall(Args args) nothrow
{
foreach (i; items)
i(args);
}
}

DelegateList!(string, int) list; // Compile OK so far
DelegateList!(string, int*) list2; // Compile OK so far
DelegateList!(string, ref int) list3; // Compile error -> How 
to make it work?


Thanks
Pham


The only way I know of is using  a template which behaves like a 
reference.
Which can be done with nullableRef I suppose. Haven't actually 
tried it.


import std.typecons : NullableRef, nullableRef;

DelegateList!(NullableRef!int)(nullableRef(some_int));