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 since the last announced version, 0.5.3:
  - SumType is now 100% @safe!
  - `match` now considers all overloads of functions passed as handlers.
  - Several bugs affecting const and immutable SumTypes have been fixed.
  - Comparison of SumTypes with the `==` operator now correctly forwards
    to the contained type's `==` operator.
  - A couple of confusing error messages have been improved.
  - Test builds on Travis CI now use both LDC and DMD.

Many thanks to Atila Neves for his contributions to this release. In particular, the changes to `match` and the `==` operator are the result of his efforts. It's been a pleasure working with him, and I hope to have more opportunities to do so.

Links:
  - Documentation: https://pbackus.github.io/sumtype/sumtype.html
  - DUB: https://sumtype.dub.pm
  - Github: https://github.com/pbackus/sumtype

On Wednesday, 21 November 2018 at 00:38:25 UTC, Paul Backus wrote:
> SumType is a generic sum type for modern D. It is meant as an alternative to `std.variant.Algebraic`.
>
> [snip]

Keep up the good work.

On Wed, Nov 21, 2018 at 12:38:25AM +0000, Paul Backus via Digitalmars-d-announce 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`.
[...]

Took a quick look at this.  Wow!  Excellent job!  Very nicely-designed API, much better than std.variant.* IMO.

Any way this could be expanded to arbitrary types like Variant? Or is that not possible without reverting to TypeInfo dependency?


T

-- 
Why have vacation when you can work?? -- EC

On Thursday, 22 November 2018 at 00:02:18 UTC, H. S. Teoh wrote:
> Any way this could be expanded to arbitrary types like Variant? Or is that not possible without reverting to TypeInfo dependency?
>
>
> T

Not possible, unfortunately--for that and other reasons.

On Wednesday, 21 November 2018 at 00:38:25 UTC, Paul Backus wrote:
> SumType is a generic sum type for modern D. It is meant as an alternative to `std.variant.Algebraic`.
>
> [...]

Thanks for the kind words! My pleasure, SumType has been what I've been wanting in D for a while. Expect more annoyances from me in the near future ;)