Hi everyone!
I usually don't post on the forums, but I got two small projects I developed as helpers for some other projects, and figured some people might have interest in them. They are registered on dub.

## Bitblob

https://github.com/Geod24/bitblob

Bitblob is a simple wrapper for hashes. While it was almost exclusively tested with 256 bits hash, it should work with any hash size.
It's a value type with 0 overhead (as in (Bitblob!256).sizeof == 32), can be initialized from an hex string or the result of `std.digest.sha : shaXXXOf()` (which is an `ubyte[XXX/8]`).
It also provides allocation-less string representation via the `void toString(scope void delegate(const(char)[]))` method.


## Minivariant

https://github.com/Geod24/minivariant

Minivariant is a "works for me" replacement of `std.variant : Algebraic`.
I just wanted a simple tagged union that did the job, but the following code does not compile:
```d
import std.variant : Algebraic;

void main ()
{
    immutable int a = 42;
    Algebraic!(int, bool, string) var;
    var = a;
}
```

```
dlang/dmd/std/variant.d(628): Error: static assert:  "Cannot store a immutable(int) in a VariantN!(16LU, int, bool, string). Valid types are (int, bool, string)"
wat.d(7):        instantiated from here: opAssign!(immutable(int))
```

I looked into fixing it, but given Variant's design (which relies heavily on `TypeInfo`) it would have been a wild goose chase. And I know I'm not the only one that needed his own tagged union (see e.g. https://github.com/s-ludwig/taggedalgebraic). It also has a `visit` method similar to std.variant, although not with delegates, as there is currently no way to merge delegates into an overload set, so you have to use an existing overload set (see the examples).


The README of each repo contains more details and examples, and the code is usually documented.

On Tuesday, 22 January 2019 at 10:26:33 UTC, Mathias Lang wrote:
> ## Minivariant
>
> https://github.com/Geod24/minivariant
>
> Minivariant is a "works for me" replacement of `std.variant : Algebraic`.
>
> [...]
>
> I looked into fixing it, but given Variant's design (which relies heavily on `TypeInfo`) it would have been a wild goose chase. And I know I'm not the only one that needed his own tagged union (see e.g. https://github.com/s-ludwig/taggedalgebraic). It also has a `visit` method similar to std.variant, although not with delegates, as there is currently no way to merge delegates into an overload set, so you have to use an existing overload set (see the examples).

I've also been through this exact process. The resulting package is on dub as `sumtype` [1]. In addition to solving the problem you noticed with `immutable`, it also works with @safe, @nogc, pure, and nothrow, and supports both delegates and overload sets with its `match` method (the equivalent of `visit`).

[1] http://sumtype.dub.pm/