Is there a solution for the following problem:

import std.variant : Algebraic;

struct A
{
    int a=2;
}

struct B
{
    int a=2;
};

void main()
{
    Algebraic!(A,B) c=A();
    writeln(c.a);
    return;
}

Error: no property a for type VariantN!(4LU, A, B)

On Saturday, 19 January 2019 at 17:40:53 UTC, sighoya wrote:
> Is there a solution for the following problem:
>
> import std.variant : Algebraic;
>
> struct A
> {
>     int a=2;
> }
>
> struct B
> {
>     int a=2;
> };
>
> void main()
> {
>     Algebraic!(A,B) c=A();
>     writeln(c.a);
>     return;
> }
>
> Error: no property a for type VariantN!(4LU, A, B)

You want the untyped version of std.variant.visit:

writeln(c.visit!(aOrB => aOrB.a));

On Saturday, 19 January 2019 at 17:51:58 UTC, Meta wrote:
> On Saturday, 19 January 2019 at 17:40:53 UTC, sighoya wrote:
>> Is there a solution for the following problem:
>>
>> import std.variant : Algebraic;
>>
>> struct A
>> {
>>     int a=2;
>> }
>>
>> struct B
>> {
>>     int a=2;
>> };
>>
>> void main()
>> {
>>     Algebraic!(A,B) c=A();
>>     writeln(c.a);
>>     return;
>> }
>>
>> Error: no property a for type VariantN!(4LU, A, B)
>
> You want the untyped version of std.variant.visit:
>
> writeln(c.visit!(aOrB => aOrB.a));

Thanks @Meta,

With the help of dlang's UFCS, we can rewrite it more idiomatically as:

import std.variant : Algebraic;

struct A
{
    int a=2;
}

struct B
{
    int a=2;
};

int a(Algebraic!(A,B) c)
{
    return cast(int)(visit!((c)=>c.a)(c));
}

void main()
{
    Algebraic!(A,B) c=A();
    writeln(c.a);
    return;
}

On Saturday, 19 January 2019 at 17:40:53 UTC, sighoya wrote:
> Is there a solution for the following problem:
>
> import std.variant : Algebraic;
>
> struct A
> {
>     int a=2;
> }
>
> struct B
> {
>     int a=2;
> };
>
> void main()
> {
>     Algebraic!(A,B) c=A();
>     writeln(c.a);
>     return;
> }
>
> Error: no property a for type VariantN!(4LU, A, B)

Try using http://code.dlang.org/packages/taggedalgebraic I find it much better.