• Vinay Sajip (15/15) Feb 22 2020 The following program won't compile if I uncomment the if
• nullptr (14/29) Feb 22 2020 The type in v isn't Complex, it's Complex!double.
• Vinay Sajip (2/3) Feb 23 2020 Ah, great. Thanks! Missed that.

Vinay Sajip <vinay_sajip yahoo.co.uk> writes:

The following program won't compile if I uncomment the if 
statement:

void main()
{
     Variant v = complex(1.0, 1.0);

//    if (v.peek!(Complex)) {
//        writeln("Complex");
//    }
     writeln(v);
}

I get the same error with v.peek!(complex), which is:

Error: template instance peek!(Complex) does not match template 
declaration peek(T)()

The variant can clearly hold a complex value. Someone please tell 
me - what am I doing wrong in the peek call?

nullptr <null p.tr> writes:

On Saturday, 22 February 2020 at 18:00:16 UTC, Vinay Sajip wrote:
 The following program won't compile if I uncomment the if 
 statement:

 void main()
 {
     Variant v = complex(1.0, 1.0);

 //    if (v.peek!(Complex)) {
 //        writeln("Complex");
 //    }
     writeln(v);
 }

 I get the same error with v.peek!(complex), which is:

 Error: template instance peek!(Complex) does not match template 
 declaration peek(T)()

 The variant can clearly hold a complex value. Someone please 
 tell me - what am I doing wrong in the peek call?

The type in v isn't Complex, it's Complex!double.

This will work the way you want:
```
void main()
{
     Variant v = complex(1.0, 1.0);

     if (v.peek!(Complex!double))
     {
         writeln("Complex");
     }

     writeln(v);
}
```

Vinay Sajip <vinay_sajip yahoo.co.uk> writes:

On Saturday, 22 February 2020 at 18:32:06 UTC, nullptr wrote:
 The type in v isn't Complex, it's Complex!double.

Ah, great. Thanks! Missed that.