I have a template

template T(alias t)
{
  pragma(msg, t.stringof);
  .... other stuff ...
}

which I use in a class and pass fields/members to.

D complains that t does not have a this.

I'd just like to print the literal text that was passed to T. (which I actually do in ctfe) This is so I can have some sort of debug output of what was passed to t.

On Friday, 19 July 2013 at 08:02:45 UTC, JS wrote:
> I have a template
>
> template T(alias t)
> {
>   pragma(msg, t.stringof);
>   .... other stuff ...
> }
>
> which I use in a class and pass fields/members to.
>
> D complains that t does not have a this.
>
> I'd just like to print the literal text that was passed to T. (which I actually do in ctfe) This is so I can have some sort of debug output of what was passed to t.

that error is probably related to what you're passing as t, which leads to the obvious question: what sort of things are you passing as t?

On Friday, 19 July 2013 at 08:08:27 UTC, John Colvin wrote:
> On Friday, 19 July 2013 at 08:02:45 UTC, JS wrote:
>> I have a template
>>
>> template T(alias t)
>> {
>>  pragma(msg, t.stringof);
>>  .... other stuff ...
>> }
>>
>> which I use in a class and pass fields/members to.
>>
>> D complains that t does not have a this.
>>
>> I'd just like to print the literal text that was passed to T. (which I actually do in ctfe) This is so I can have some sort of debug output of what was passed to t.
>
> that error is probably related to what you're passing as t, which leads to the obvious question: what sort of things are you passing as t?

Yeah, I forgot to add a private local variable and it was complaining... I didn't realize this because it was working before I started refactoring stuff.

I guess it would be nice to assert a proper error if t doesn't exist rather than the error it gave. (I'm suppose to be passing it a field of a class so it should exist)

Is there any way to test for "existance" of an alias?

On 07/19/2013 02:02 AM, JS wrote:

> On Friday, 19 July 2013 at 08:08:27 UTC, John Colvin wrote:
>> On Friday, 19 July 2013 at 08:02:45 UTC, JS wrote:
>>> I have a template
>>>
>>> template T(alias t)
>>> {
>>>  pragma(msg, t.stringof);
>>>  .... other stuff ...
>>> }
>>>
>>> which I use in a class and pass fields/members to.

I read everything you wrote and came up with this:

template T(alias t)
{
    pragma(msg, t.stringof);
}

class C
{
    int i;

    void foo()
    {
        mixin T!i;
        mixin T!j;
    }
}

void main()
{
    auto c = new C();
}

>>> D complains that t does not have a this.

Hm... It does not do that for me.

> I guess it would be nice to assert a proper error if t doesn't exist
> rather than the error it gave.

That is exactly what dmd does:

Error: undefined identifier j, did you mean variable i?

> (I'm suppose to be passing it a field of
> a class so it should exist)
>
> Is there any way to test for "existance" of an alias?

Probably. But I suspect your code is something different from what I understood.

Ali