convert between types

[Kapendev]

On Friday, 2 January 2026 at 13:09:44 UTC, Lars Johansson wrote:
>     I'm writing a simple program just to get started (se below).
>      mat[i][z] = z; this line generate following error:
>      cannot implicitly convert expression `z` of type `ulong` 
> to `char`

Simple as:

```d
mat[i][z] = cast(char) z;
```