Template with template?

[Chris]

On Thursday, 20 March 2014 at 16:32:34 UTC, Vladimir Panteleev 
wrote:
> On Thursday, 20 March 2014 at 16:28:46 UTC, Chris wrote:
>> How can I instantiate Person with Trait, i.e. a template with 
>> a template?
>>
>> struct Trait(T0, T1) {
>>  T0 name;
>>  T1 value;
>>  T1[T0] map;
>>
>>  this(T0 name, T1 value) {
>>    this.name = name;
>>    this.value = value;
>>    map[name] = value;
>>  }
>> }
>>
>> class Person(T) {
>>  T traits[];
>>
>>  void addTrait(T trait) {
>>    traits ~= trait;
>>  }
>> }
>>
>>
>> void main()
>> {
>>  auto trait1 = Trait!(string, string)("Name", "John");
>>  auto trait2 = Trait!(string, int)("Age", 42);
>>  writefln(%s", trait1.map);
>>  writefln(%s", trait2.map);
>>  // above code compiles and works
>> }
>
> Person!(Trait!(string, string)) person;
>
> -- or --
>
> alias MyTrait = Trait!(string, string);
> Person!MyTrait person;
>
> Note that this approach won't let you have traits with 
> different parameters within the same Person type.

Yep, I've already tried this (sorry I should've mentioned it!). 
But I don't want this restriction.