template struct question

[Ali Çehreli]

On 2/12/25 12:55 PM, WhatMeWorry wrote:

 > struct HexBoard(F,I)
 > {
 >      this(F d, I r, I c) {}
 >      //void displayHexBoard(HexBoard!(F,I) h) {}  // this compiles fine!
 > }
 >
 > void displayHexBoard(HexBoard!(F,I) h) {}  // error undefined identifier
 > F and I

Would isInstanceOf be useful? (Which is actually optional.) It 
necessitated two aliases in the struct:

void main()
{
     struct HexBoard(F, I)
     {
         alias Float = F;
         alias Int = I;

         this(F d, I r, I c) {}
     }

     import std.traits : isInstanceOf;
     void displayHexBoard(HB)(HB h)
         if (isInstanceOf!(HexBoard, HB))
     {
         pragma(msg, "The types are ", HB.Float, " and ", HB.Int);
     }

     auto h1 = HexBoard!(float,uint)(.25, 3, 7);
     displayHexBoard(h1);
}

Ali