• Andre (30/30) Mar 24 2015 Hi,
• Andre (2/2) Mar 24 2015 Definition of BoolRef:
• Gary Willoughby (3/5) Mar 24 2015 Could template alias parameters not be used here?
• Andre (14/19) Mar 24 2015 Event is defined as struct Event(T...){}.
• Dicebot (5/8) Mar 24 2015 This sounds like a bad idea because in D `ref` is not a type

"Andre" <andre s-e-a-p.de> writes:

Hi,

Namespace helped me to get following template working.

struct PrimitiveRef(T)
{
	private T* _value;

	 property
	ref inout(T) get() inout pure nothrow {
		assert(_value);
		return *_value;
	}
	
	alias get this;
	
	this(T val) {
		_value = new T(val);
	}
}

The use case is a type tuple where you cannot use the keyword ref.

Example usage: ( This is an extract from a little event framework)

Event!(Object, BoolRef) onClose;

onClose.attach(&onFormClose); // function or delegate

void onFormClose(Object o, BoolRef canClose)
{
     canClose = false;
}

I think it is useful to add to std.typecons as there is no 
possibility
to use ref for type tuples.

Kind regards
André

"Andre" <andre s-e-a-p.de> writes:

Definition of BoolRef:

alias BoolRef = PrimitiveRef!bool;

"Gary Willoughby" <dev nomad.so> writes:

On Tuesday, 24 March 2015 at 15:38:04 UTC, Andre wrote:
 The use case is a type tuple where you cannot use the keyword 
 ref.

Could template alias parameters not be used here?

http://dlang.org/template.html#aliasparameters

"Andre" <andre s-e-a-p.de> writes:

On Tuesday, 24 March 2015 at 16:58:48 UTC, Gary Willoughby wrote:
 On Tuesday, 24 March 2015 at 15:38:04 UTC, Andre wrote:
 The use case is a type tuple where you cannot use the keyword 
 ref.

 Could template alias parameters not be used here?

 http://dlang.org/template.html#aliasparameters

Event is defined as struct Event(T...){}.
That way the actual number of parameters is very flexible.

I just checked template alias parameters. Also here the ref 
keyword
is not allowed:

	struct Event(alias x)
	{
		private void delegate(x)[] _dlgArr;
	}

	Event!(ref bool) onEvent;

Error is thrown: expression expected not ref.

Kind regards
André

"Dicebot" <public dicebot.lv> writes:

On Tuesday, 24 March 2015 at 15:38:04 UTC, Andre wrote:
 I think it is useful to add to std.typecons as there is no 
 possibility
 to use ref for type tuples.

This sounds like a bad idea because in D `ref` is not a type 
qualifier and thus not part of a type. Not though that you can 
apply ref storage class to type tuple as a whole:

void foo(T...)(ref T args) { }