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

[Steven Schveighoffer via Digitalmars-d-learn]

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