Re: variant .init value

[bauss via Digitalmars-d-learn]

On Thursday, 7 February 2019 at 07:33:50 UTC, Norm wrote:

Hi,

I'm trying to use Variant in a struct and want a default init 
value like so:


---
struct S {
  Variant v = Variant(10);
}
void main() {auto s = S();}

but when I try to build this I get the following error:

dmd2/linux/bin64/../../src/phobos/std/variant.d(661): Error: 
memcpy cannot be interpreted at compile time, because it has no 
available source code

Error: cannot interpret  at compile time
---

I don't particularly need or want this to be available at 
compile time, I really only want the struct to have a default 
value when instantiated at runtime.


Is there a way to do this with a Variant member?

Thanks,
Norm


I know this is not ideal, but here is a "workaround":

struct S {
  Variant v;

  static S opCall()
  {
  S s;
  s.v = Variant(10);
  return s;
  }
}

Would have worked better if structs allowed default ctor in D, 
but they don't unfortunately.

Re: variant .init value

[Norm via Digitalmars-d-learn]

On Thursday, 7 February 2019 at 07:44:17 UTC, Alex wrote:

On Thursday, 7 February 2019 at 07:33:50 UTC, Norm wrote:

[...]


Hmm... found something similar from 2014...
https://issues.dlang.org/show_bug.cgi?id=11864


Thanks, I've added a comment to that bug report.

Cheers,
Norm

Re: variant .init value

[Alex via Digitalmars-d-learn]

On Thursday, 7 February 2019 at 07:33:50 UTC, Norm wrote:

Hi,

I'm trying to use Variant in a struct and want a default init 
value like so:


---
struct S {
  Variant v = Variant(10);
}
void main() {auto s = S();}

but when I try to build this I get the following error:

dmd2/linux/bin64/../../src/phobos/std/variant.d(661): Error: 
memcpy cannot be interpreted at compile time, because it has no 
available source code

Error: cannot interpret  at compile time
---

I don't particularly need or want this to be available at 
compile time, I really only want the struct to have a default 
value when instantiated at runtime.


Is there a way to do this with a Variant member?

Thanks,
Norm


Hmm... found something similar from 2014...
https://issues.dlang.org/show_bug.cgi?id=11864

variant .init value

[Norm via Digitalmars-d-learn]

Hi,

I'm trying to use Variant in a struct and want a default init 
value like so:


---
struct S {
  Variant v = Variant(10);
}
void main() {auto s = S();}

but when I try to build this I get the following error:

dmd2/linux/bin64/../../src/phobos/std/variant.d(661): Error: 
memcpy cannot be interpreted at compile time, because it has no 
available source code

Error: cannot interpret  at compile time
---

I don't particularly need or want this to be available at compile 
time, I really only want the struct to have a default value when 
instantiated at runtime.


Is there a way to do this with a Variant member?

Thanks,
Norm