give below template struct, how can I list the members x, y and z? I've tried something with OriginalType and TemplateOf but no luck... it seems if I do foo!"str1" the "str1" became "part of type"? give .stringof from typeof(__traits(getMember, foo, field)) I thought the type would be foo!string or something.

Here's the code:

template foo(string s = null)
{
	@nogc
	struct foo
	{
		int n;

		enum x = foo!"str1"(10);
		enum y = foo!"str2"(20);
		enum z = foo!"str3"(30);

		enum myEnum { none }

		void someMethod() { }
	}
}

not working listener:

void list()
{
	static foreach(field; __traits(allMembers, foo!()))
	{{
		alias m = __traits(getMember, foo!(), field);
		static if(!isType!m && __traits(isSame, OriginalType!(typeof(m)), foo))
		{
			writefln("field = [%s]", field);
		}
	}}
}

On Friday, 19 March 2021 at 07:14:46 UTC, Jack wrote:
> give below template struct, how can I list the members x, y and z? I've tried something with OriginalType and TemplateOf but no luck... it seems if I do foo!"str1" the "str1" became "part of type"? give .stringof from typeof(__traits(getMember, foo, field)) I thought the type would be foo!string or something.

Template parameter cannot only be types but also values, including strings. If you instantiate a template with different values you get different types.

--
struct foo(T) { }
struct bar(string s) {}

alias a = foo!string; // type of a is foo!string
alias b = bar!"str1"; // type of b is bar!"str1"
alias c = bar!"str2"; // typo of c is bar!"str2"
static assert (!is(typeof(c) == typeof(b)));
--

On Friday, 19 March 2021 at 07:14:46 UTC, Jack wrote:
> give below template struct, how can I list the members x, y and z? I've tried something with OriginalType and TemplateOf but no luck... it seems if I do foo!"str1" the "str1" became "part of type"? give .stringof from typeof(__traits(getMember, foo, field)) I thought the type would be foo!string or something.

You want std.traits.isInstanceOf:

    static if(!isType!m && isInstanceOf!(foo, typeof(m)))

On Friday, 19 March 2021 at 07:56:26 UTC, Panke wrote:
> On Friday, 19 March 2021 at 07:14:46 UTC, Jack wrote:
>> give below template struct, how can I list the members x, y and z? I've tried something with OriginalType and TemplateOf but no luck... it seems if I do foo!"str1" the "str1" became "part of type"? give .stringof from typeof(__traits(getMember, foo, field)) I thought the type would be foo!string or something.
>
> Template parameter cannot only be types but also values, including strings. If you instantiate a template with different values you get different types.

that design is a bit different but may be worth, gonna get used to it

> --
> struct foo(T) { }
> struct bar(string s) {}
>
> alias a = foo!string; // type of a is foo!string
> alias b = bar!"str1"; // type of b is bar!"str1"
> alias c = bar!"str2"; // typo of c is bar!"str2"
> static assert (!is(typeof(c) == typeof(b)));
> --

On Friday, 19 March 2021 at 08:54:50 UTC, Paul Backus wrote:
> On Friday, 19 March 2021 at 07:14:46 UTC, Jack wrote:
>> give below template struct, how can I list the members x, y and z? I've tried something with OriginalType and TemplateOf but no luck... it seems if I do foo!"str1" the "str1" became "part of type"? give .stringof from typeof(__traits(getMember, foo, field)) I thought the type would be foo!string or something.
>
> You want std.traits.isInstanceOf:
>
>     static if(!isType!m && isInstanceOf!(foo, typeof(m)))

thanks this works fine outside a method but not in a static method. what am I missing?

void main()
{
        // doesn't print anything
	Foo.list();
}

alias Foo = foo!();

template foo(string s = null)
{
	@nogc
	struct foo
	{
		int n;

		enum x = foo!"str1"(10);
		enum y = foo!"str2"(20);
		enum z = foo!"str3"(30);

		enum myEnum { none }

		void someMethod() { }

		static void list()
		{
			//writeln("members = ", [__traits(allMembers, foo!())]);
			static foreach(field; __traits(allMembers, foo!()))
			{{
				alias m = __traits(getMember, foo!(), field);
				static if(!isType!m && isInstanceOf!(foo, typeof(m)))
				{
					writefln("field = [%s]", field);
				}
			}}
		}
	}
}

On Friday, 19 March 2021 at 16:41:11 UTC, Jack wrote:

> thanks this works fine outside a method but not in a static method. what am I missing?

Reading the manual ;)

> To use isInstanceOf to check the identity of a template while inside of said template, use TemplateOf.

On 3/19/21 12:41 PM, Jack wrote:
> On Friday, 19 March 2021 at 08:54:50 UTC, Paul Backus wrote:
>> On Friday, 19 March 2021 at 07:14:46 UTC, Jack wrote:
>>> give below template struct, how can I list the members x, y and z? I've tried something with OriginalType and TemplateOf but no luck... it seems if I do foo!"str1" the "str1" became "part of type"? give .stringof from typeof(__traits(getMember, foo, field)) I thought the type would be foo!string or something.
>>
>> You want std.traits.isInstanceOf:
>>
>>     static if(!isType!m && isInstanceOf!(foo, typeof(m)))
> 
> thanks this works fine outside a method but not in a static method. what am I missing?
> 
> void main()
> {
>          // doesn't print anything
>      Foo.list();
> }
> 
> alias Foo = foo!();
> 
> template foo(string s = null)
> {
>      @nogc
>      struct foo
>      {
>          int n;
> 
>          enum x = foo!"str1"(10);
>          enum y = foo!"str2"(20);
>          enum z = foo!"str3"(30);
> 
>          enum myEnum { none }
> 
>          void someMethod() { }
> 
>          static void list()
>          {
>              //writeln("members = ", [__traits(allMembers, foo!())]);
>              static foreach(field; __traits(allMembers, foo!()))
>              {{
>                  alias m = __traits(getMember, foo!(), field);
>                  static if(!isType!m && isInstanceOf!(foo, typeof(m)))

foo in this context is the *instantiated* foo (i.e. the struct foo above). What you want is `isIsntanceOf!(.foo, typeof(m))`

-Steve

On Friday, 19 March 2021 at 17:40:39 UTC, frame wrote:
> On Friday, 19 March 2021 at 16:41:11 UTC, Jack wrote:
>
>> thanks this works fine outside a method but not in a static method. what am I missing?
>
> Reading the manual ;)
>
>> To use isInstanceOf to check the identity of a template while inside of said template, use TemplateOf.

indeed, it shwos an example on how to use that in a static function

On Saturday, 20 March 2021 at 00:16:06 UTC, Steven Schveighoffer wrote:
> On 3/19/21 12:41 PM, Jack wrote:
>> On Friday, 19 March 2021 at 08:54:50 UTC, Paul Backus wrote:
>>> On Friday, 19 March 2021 at 07:14:46 UTC, Jack wrote:
>>>> give below template struct, how can I list the members x, y and z? I've tried something with OriginalType and TemplateOf but no luck... it seems if I do foo!"str1" the "str1" became "part of type"? give .stringof from typeof(__traits(getMember, foo, field)) I thought the type would be foo!string or something.
>>>
>>> You want std.traits.isInstanceOf:
>>>
>>>     static if(!isType!m && isInstanceOf!(foo, typeof(m)))
>> 
>> thanks this works fine outside a method but not in a static method. what am I missing?
>> 
>> void main()
>> {
>>          // doesn't print anything
>>      Foo.list();
>> }
>> 
>> alias Foo = foo!();
>> 
>> template foo(string s = null)
>> {
>>      @nogc
>>      struct foo
>>      {
>>          int n;
>> 
>>          enum x = foo!"str1"(10);
>>          enum y = foo!"str2"(20);
>>          enum z = foo!"str3"(30);
>> 
>>          enum myEnum { none }
>> 
>>          void someMethod() { }
>> 
>>          static void list()
>>          {
>>              //writeln("members = ", [__traits(allMembers, foo!())]);
>>              static foreach(field; __traits(allMembers, foo!()))
>>              {{
>>                  alias m = __traits(getMember, foo!(), field);
>>                  static if(!isType!m && isInstanceOf!(foo, typeof(m)))
>
> foo in this context is the *instantiated* foo (i.e. the struct foo above). What you want is `isIsntanceOf!(.foo, typeof(m))`
>
> -Steve

Thank you Steve, that what I was looking for. Funny thing, I totally forget about the . operator