Hi,
I want to do exactly the same as described in
http://d.puremagic.com/issues/show_bug.cgi?id=4536 . The problem is I
can't even get the workaround to work. Dmd complains about the following
template:
---------------------------------------------------------------
template Init(T...)
{
    alias (Tuple!T.init).expand Init;
}
---------------------------------------------------------------

Dmd output:
---------------------------------------------------------------
test.d(18): basic type expected, not (
test.d(18): found '!' when expecting ')'
test.d(18): semicolon expected to close alias declaration
test.d(18): no identifier for declarator T.init
test.d(18): semicolon expected, not ')'
test.d(18): Declaration expected, not ')'
---------------------------------------------------------------

Is it possible that this has recently stopped working? Is this a bug in dmd or is this the expected behavior? Is there any other way to achieve the same thing?
-- 
Johannes Pfau

Johannes Pfau <spam@example.com> wrote:

> Hi,
> I want to do exactly the same as described in
> http://d.puremagic.com/issues/show_bug.cgi?id=4536 . The problem is I
> can't even get the workaround to work. Dmd complains about the following
> template:
> ---------------------------------------------------------------
> template Init(T...)
> {
>     alias (Tuple!T.init).expand Init;
> }
> ---------------------------------------------------------------
>
> Dmd output:
> ---------------------------------------------------------------
> test.d(18): basic type expected, not (
> test.d(18): found '!' when expecting ')'
> test.d(18): semicolon expected to close alias declaration
> test.d(18): no identifier for declarator T.init
> test.d(18): semicolon expected, not ')'
> test.d(18): Declaration expected, not ')'
> ---------------------------------------------------------------
>
> Is it possible that this has recently stopped working? Is this a bug in
> dmd or is this the expected behavior? Is there any other way to achieve
> the same thing?

This works for me:

template Init( T ) {
    alias TypeTuple!( T.init ) Init;
}

template Init( T, U... ) {
    alias TypeTuple!( T.init, Init!U ) Init;
}


-- 
Simen

On Thu, Aug 19, 2010 at 21:51, Simen kjaeraas <simen.kjaras@gmail.com>wrote:

> Johannes Pfau <spam@example.com> wrote:
>
>  Hi,
>> I want to do exactly the same as described in http://d.puremagic.com/issues/show_bug.cgi?id=4536 . The problem is I can't even get the workaround to work. Dmd complains about the following template:
>> ---------------------------------------------------------------
>> template Init(T...)
>> {
>
>  alias (Tuple!T.init).expand Init;
>> }
>>
>
Hmm, I'm pretty sure it used to worked, because as one time that's what I used.

Anyway, Simen's solutions is better, a bit less dependency. TypeTuple is a bit more universal than Tuple.

Simen:

>
> template Init( T ) {
>    alias TypeTuple!( T.init ) Init;
> }
>
> template Init( T, U... ) {
>    alias TypeTuple!( T.init, Init!U ) Init;
> }
>
>
And, looking in my codebase, here is what I'm using ;)

template Init(T...)
{
    T Init;
}

It's so simple...
I think I found this before the bug report and then forgot about it and
copied an old version. I'll update the bug report accordingly, if the latter
version works for you.

Philippe

Philippe Sigaud <philippe.sigaud@gmail.com> wrote:

> And, looking in my codebase, here is what I'm using ;)
>
> template Init(T...)
> {
>     T Init;
> }

Doh. I believe this is slightly better, though:

template Init( T... ) {
    enum T Init;
}

:p

-- 
Simen

On Thu, Aug 19, 2010 at 22:16, Simen kjaeraas <simen.kjaras@gmail.com>wrote:

> Philippe Sigaud <philippe.sigaud@gmail.com> wrote:
>
>  And, looking in my codebase, here is what I'm using ;)
>>
>> template Init(T...)
>> {
>>    T Init;
>> }
>>
>
> Doh. I believe this is slightly better, though:
>
> template Init( T... ) {
>    enum T Init;
> }
>
> :p
>

What, that's *five* more characters, five! I win, I win!

More seriously, yours might be more 'solid', but isn't enum implicit in this case?

Anyway, T.init should exist, since "T Init;" works...

Philippe

Philippe Sigaud <philippe.sigaud@gmail.com> wrote:

> What, that's *five* more characters, five! I win, I win!

;'(

> More seriously, yours might be more 'solid', but isn't enum implicit in this
> case?

Seems you are right. I thought the template would work as a namespace,
giving this situation:

Init!int = 4;
int a = Init!int; // What, 4?!

But such is not the case.


> Anyway, T.init should exist, since "T Init;" works...

Indeed.


-- 
Simen

On 19.08.2010 22:07, Philippe Sigaud wrote:
> And, looking in my codebase, here is what I'm using ;)
> 
> template Init(T...)
> {
>     T Init;
> }
> 
> It's so simple...
> I think I found this before the bug report and then forgot about it and
> copied an old version. I'll update the bug report accordingly, if the
> latter version works for you.

Great, that works!  Thanks for the quick reply.
-- 
Johannes Pfau