Thread overview
template instance does not match template declaration
Jan 08
Meta
January 08
Hi,

On my first attempt to create a templated class, I'm hitting an issue that I can't seem to resolve.

I've dustmite'd the code down to:

class Cache(O, K, F)
{
}


void main()
{
	class BasicObject
	{
	}

	BasicObject lookupBasicObject() {
	}

        Cache!(BasicObject, string, lookupBasicObject);
}


and I'm hitting the following error:

cache.d(23): Error: template instance Cache!(BasicObject, string, lookupBasicObject) does not match template declaration Cache(O, K, F)

Any help would be much appreciated in understanding what I am doing wrong.

Thanks.

Take care,
Fabrice.
January 08
On Sunday, 8 January 2017 at 03:27:26 UTC, Fabrice Marie wrote:
> Hi,
>
> On my first attempt to create a templated class, I'm hitting an issue that I can't seem to resolve.
>
> I've dustmite'd the code down to:
>
> class Cache(O, K, F)
> {
> }
>
>
> void main()
> {
> 	class BasicObject
> 	{
> 	}
>
> 	BasicObject lookupBasicObject() {
> 	}
>
>         Cache!(BasicObject, string, lookupBasicObject);
> }
>
>
> and I'm hitting the following error:
>
> cache.d(23): Error: template instance Cache!(BasicObject, string, lookupBasicObject) does not match template declaration Cache(O, K, F)
>
> Any help would be much appreciated in understanding what I am doing wrong.
>
> Thanks.
>
> Take care,
> Fabrice.

By default template parameters are Types. lookupBasicObject is not.

change this `class Cache(O, K, F)` to `class Cache(O, K, alias F)`
and it should work.

January 08
On Sunday, 8 January 2017 at 03:27:26 UTC, Fabrice Marie wrote:

> void main()
> {
>       ....
>       Cache!(BasicObject, string, lookupBasicObject);
> }

In addition to what Nicholas Wilson said, what you're doing here is the equivalent of writing `int;`. It doesn't make any sense as Cache!(...) is a type, and you are declaring a variable of that type... except you're not providing a variable name so the syntax is wrong. After you've fixed the other problem change it to this:

Cache!(BasicObject, string, lookupBasicObject) c;
January 15
On Sunday, 8 January 2017 at 05:45:52 UTC, Meta wrote:
> On Sunday, 8 January 2017 at 03:27:26 UTC, Fabrice Marie wrote:
>
>> void main()
>> {
>>       ....
>>       Cache!(BasicObject, string, lookupBasicObject);
>> }
>
> In addition to what Nicholas Wilson said, what you're doing here is the equivalent of writing `int;`. It doesn't make any sense as Cache!(...) is a type, and you are declaring a variable of that type... except you're not providing a variable name so the syntax is wrong. After you've fixed the other problem change it to this:
>
> Cache!(BasicObject, string, lookupBasicObject) c;

Thanks a lot! exactly what I needed.