Hi all,

I am trying to implement `opIndex` (e.g. T[i]) for types in a struct. So for I have `length`:

```d
struct TList(T...)
{
  enum long length = T.length;
}
```

and have tried including

```d
alias opIndex(long i) = T[i];
```

or

```d
alias opIndex(alias i) = T[i];
```

called with

```d
alias tList = AliasSeq!(bool, string, ubyte, short, ushort);
TList!(tList)[0];
```

but that doesn't work and I get the error:

```d
opIndex cannot deduce function from argument types !()(int), candidates are:
opIndex(long i)

```

On Monday, 24 August 2020 at 14:19:14 UTC, data pulverizer wrote:
> I am trying to implement `opIndex` (e.g. T[i]) for types in a struct.

p.s. I know I could just write a separate `get` template, but `AliasSeq` has opIndex and opSlice operators, so I wonder whether it is possible to get those in this case.

On Monday, 24 August 2020 at 14:19:14 UTC, data pulverizer wrote:
> I am trying to implement `opIndex` (e.g. T[i]) for types in a struct. So for I have `length`:

Can't really do that, the operator overloads work on instances instead of static types.

AliasSeq is magical because it just gives a name to something built-into the compiler.

On Monday, 24 August 2020 at 14:36:22 UTC, Adam D. Ruppe wrote:
> On Monday, 24 August 2020 at 14:19:14 UTC, data pulverizer wrote:
>> I am trying to implement `opIndex` (e.g. T[i]) for types in a struct. So for I have `length`:
>
> Can't really do that, the operator overloads work on instances instead of static types.
>
> AliasSeq is magical because it just gives a name to something built-into the compiler.

Fair enough, it's not a show stopper.

On Monday, 24 August 2020 at 14:19:14 UTC, data pulverizer wrote:
> Hi all,
>
> I am trying to implement `opIndex` (e.g. T[i]) for types in a struct. So for I have `length`:
>
> ```d
> struct TList(T...)
> {
>   enum long length = T.length;
> }
> ```
>
> and have tried including
>
> ```d
> alias opIndex(long i) = T[i];
> ```
>
> or
>
> ```d
> alias opIndex(alias i) = T[i];
> ```
>
> called with
>
> ```d
> alias tList = AliasSeq!(bool, string, ubyte, short, ushort);
> TList!(tList)[0];
> ```
>
> but that doesn't work and I get the error:
>
> ```d
> opIndex cannot deduce function from argument types !()(int), candidates are:
> opIndex(long i)
>
> ```

This is an interesting syntax, and it reminds me of Python's generic syntax. Will be interested to see how you use type opIndex.