How do I check if this field is of this template struct?

[Jack]

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