• Yui Hosaka (29/29) Jan 10 2019 I want to do something like this:
• Paul Backus (4/13) Jan 10 2019 You can get the arguments of a template instance as an AliasSeq
• Yui Hosaka (2/17) Jan 11 2019 It seems a good choice to me. Thank you!

Yui Hosaka <hos hos.ac> writes:

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?

Paul Backus <snarwin gmail.com> writes:

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

Yui Hosaka <hos hos.ac> writes:

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!