Re: Getting template parameters by its name

2019-01-11 Thread Yui Hosaka via Digitalmars-d-learn 

On Friday, 11 January 2019 at 06:13:11 UTC, Paul Backus wrote:

On Friday, 11 January 2019 at 04:59:50 UTC, Yui Hosaka wrote:

I want to do something like this:


template S(T) {
}

void main() {
  pragma(msg, S!(int).T);  // Error: no property `T` for type 
`void`

}



You can get the arguments of a template instance as an AliasSeq 
using `std.traits.TemplateArgsOf`.


https://dlang.org/phobos/std_traits.html#TemplateArgsOf


It seems a good choice to me. Thank you!

Re: Getting template parameters by its name

2019-01-10 Thread Paul Backus via Digitalmars-d-learn 

On Friday, 11 January 2019 at 04:59:50 UTC, Yui Hosaka wrote:

I want to do something like this:


template S(T) {
}

void main() {
  pragma(msg, S!(int).T);  // Error: no property `T` for type 
`void`

}



You can get the arguments of a template instance as an AliasSeq 
using `std.traits.TemplateArgsOf`.


https://dlang.org/phobos/std_traits.html#TemplateArgsOf

Getting template parameters by its name

2019-01-10 Thread Yui Hosaka via Digitalmars-d-learn 

I want to do something like this:


template S(T) {
}

void main() {
  pragma(msg, S!(int).T);  // Error: no property `T` for type 
`void`

}


Using alias, it is possible to get T by another name:


template S(T) {
  alias t = T;
}

void main() {
  pragma(msg, S!(int).t);
}


But the same identifier cannot be used:


template S(T) {
  alias T = T;  // Error: `alias T = T;` cannot alias itself, use 
a qualified name to create an overload set

}

void main() {
  pragma(msg, S!(int).T);
}


Is there any nice way that `S!(int).T` works?