On Thursday, 20 February 2020 at 16:08:43 UTC, Per Nordlöw wrote:
> On Wednesday, 19 February 2020 at 06:52:04 UTC, Ernesto Castellotti wrote:
>> How about including SumType (https://github.com/pbackus/sumtype) in Phobos?
>>
>> We know that std.variant.Algebraic has problems (nogc, nothrow etc), SumType would be a wonderful solution to provide a tagged
>
> I also have an alternative to std.variant.Algebraic at
>
> https://github.com/nordlow/phobos-next/blob/master/src/nxt/variant.d
>
> which is @safe pure nothrow @nogc when possible and doesn't rely on TypeInfo. No explicit support for @BetterC.

Fairly sad how common of a need it is: https://github.com/Geod24/minivariant#minivariant-simple-focused-variant-library

On Thursday, 20 February 2020 at 16:08:43 UTC, Per Nordlöw wrote:
> On Wednesday, 19 February 2020 at 06:52:04 UTC, Ernesto Castellotti wrote:
>> How about including SumType (https://github.com/pbackus/sumtype) in Phobos?
>>
>> We know that std.variant.Algebraic has problems (nogc, nothrow etc), SumType would be a wonderful solution to provide a tagged
>
> I also have an alternative to std.variant.Algebraic at
>
> https://github.com/nordlow/phobos-next/blob/master/src/nxt/variant.d
>
> which is @safe pure nothrow @nogc when possible and doesn't rely on TypeInfo. No explicit support for @BetterC.

This is missing what I consider the most important feature of Algebraic and SumType, which is the ability to switch on the type index with compile-time exhaustiveness checking (i.e., `visit` or `match`).

The amount of @trusted code is also a red flag. I've already found one mistake in it [1], which means there are probably at least a couple more that I didn't catch.

[1] https://github.com/nordlow/phobos-next/blob/master/src/nxt/variant.d#L226-L228

On Thursday, 20 February 2020 at 17:14:13 UTC, Paul Backus wrote:
> The amount of @trusted code is also a red flag. I've already found one mistake in it [1], which means there are probably at least a couple more that I didn't catch.
>
> [1] https://github.com/nordlow/phobos-next/blob/master/src/nxt/variant.d#L226-L228

I see now that the private function `as` should be qualified as @system.

Is this the mistake you are thinking about?

On Thursday, 20 February 2020 at 17:40:46 UTC, Per Nordlöw wrote:
> On Thursday, 20 February 2020 at 17:14:13 UTC, Paul Backus wrote:
>> The amount of @trusted code is also a red flag. I've already found one mistake in it [1], which means there are probably at least a couple more that I didn't catch.
>>
>> [1] https://github.com/nordlow/phobos-next/blob/master/src/nxt/variant.d#L226-L228
>
> I see now that the private function `as` should be qualified as @system.
>
> Is this the mistake you are thinking about?

In the `else` branch of the `static if` statement, if `T` has both a copy constructor and a destructor, the copy constructor is skipped but the destructor will still be called.

On Thursday, 20 February 2020 at 18:23:45 UTC, Paul Backus wrote:
> In the `else` branch of the `static if` statement, if `T` has both a copy constructor and a destructor, the copy constructor is skipped but the destructor will still be called.

I see. Thanks. I'll consider removing the template flag `memoryPacked`.