sumtype 0.3.0

[Per Nordlöw]

On Sunday, 6 May 2018 at 19:18:02 UTC, Paul Backus wrote:
> SumType is a generic sum type for modern D. It is meant as an 
> alternative to `std.variant.Algebraic`.
>
> Features:
>   - Pattern matching, including support for structural matching 
> (*)
>   - Self-referential types, using `This`
>   - Works with `pure`, `@safe`, `@nogc`, and `immutable` (*)
>   - Zero runtime overhead compared to hand-written C
>     - No heap allocation
>     - Does not rely on runtime type information (`TypeInfo`) (*)
>
> Starred features (*) are those that are missing from 
> `Algebraic`.
>
> Code examples are available in the documentation (linked below).
>
> New in this release:
>   - The list of types allowed in a sum type is now public
>   - Implicit qualifier conversions are now allowed in pattern 
> matching
>   - Better code examples in the documentation
>
> This library is a work in progress. If you have a use case 
> you'd like to see supported, or an API you'd like to see 
> implemented, please get in touch!
>
> Documentation: https://pbackus.github.io/sumtype/sumtype.html
> DUB: https://code.dlang.org/packages/sumtype
> Github: https://github.com/pbackus/sumtype

Nice.

I've written something similar in LightAlgebraic at

https://github.com/nordlow/phobos-next/blob/master/src/vary.d#L30

which is also significantly faster than `std.typecons.Algebraic`.

Has the same features as SumType except for

- Self-referential types, using `This` and
- pattern matching

Note that the `memoryPacked` flag being `true` hasn't been 
thoroughly tested.

Your're free to copy an ideas or features in `LightAlgebraic` 
into `SumType`.