digitalmars.D.announce - sumtype 0.10.0: multiple dispatch
- Paul Backus (46/46) Sep 23 2020 SumType is a generic sum type for modern D. It is designed to be
- Bruce Carneal (2/6) Sep 23 2020 Sure looks like a strong advance. Hope it sees a lot of use.
- WebFreak001 (5/8) Sep 24 2020 Seems like dub.pm is still down, has been broken since like 6
- vitamin (19/69) Oct 27 2020 Hello,
- Paul Backus (4/22) Oct 27 2020 It's a bug in the new version. Thanks for reporting. I've opened
SumType is a generic sum type for modern D. It is designed to be an improved alternative to `std.variant.Algebraic`. Features: - Pattern matching, including: - Match-by-introspection ("if it compiles, it matches") (★) - Multiple dispatch (★) - Support for self-referential types (`This`). - Works with `pure`, ` safe`, ` nogc`, `nothrow`, and `immutable` (★) - Compatible with `-betterC` and `-dip1000` (★) - 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`. The big new feature in this release is multiple dispatch: you can pass multiple SumType arguments to a single `match` call, and it will pass each of those SumTypes' values as a separate argument to the selected handler. If you're used to calling `match` with UFCS, the syntax for passing multiple arguments may take some getting used to. I recommend the following idiom: bool sameDimensions(Point p1, Point p2) { // Set up your handlers first alias doMatch = match!( (Point2D _1, Point2D _2) => true, (Point3D _1, Point3D _2) => true, (_1, _2) => false ); // Now make the actual call return doMatch(p1, p2); } Other improvements since 0.9.0, the last announced version: - SumTypes can be used as keys in associative arrays - isSumType!T is now true if T implicitly converts to a SumType - sumtype's license has been changed from MIT to Boost 1.0 - Member types with non-const `opEquals` overloads finally work correctly - Various other bug fixes and documentation improvements Links: - Documentation: https://pbackus.github.io/sumtype/sumtype.html - DUB: https://sumtype.dub.pm - Github: https://github.com/pbackus/sumtype
Sep 23 2020
On Thursday, 24 September 2020 at 02:28:11 UTC, Paul Backus wrote:SumType is a generic sum type for modern D. It is designed to be an improved alternative to `std.variant.Algebraic`. [...]Sure looks like a strong advance. Hope it sees a lot of use.
Sep 23 2020
On Thursday, 24 September 2020 at 02:28:11 UTC, Paul Backus wrote:[...] - DUB: https://sumtype.dub.pm - Github: https://github.com/pbackus/sumtypeSeems like dub.pm is still down, has been broken since like 6 months now :/ But your library looks really powerful, would love to see sumtype be included in phobos!
Sep 24 2020
On Thursday, 24 September 2020 at 02:28:11 UTC, Paul Backus wrote:SumType is a generic sum type for modern D. It is designed to be an improved alternative to `std.variant.Algebraic`. Features: - Pattern matching, including: - Match-by-introspection ("if it compiles, it matches") (★) - Multiple dispatch (★) - Support for self-referential types (`This`). - Works with `pure`, ` safe`, ` nogc`, `nothrow`, and `immutable` (★) - Compatible with `-betterC` and `-dip1000` (★) - 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`. The big new feature in this release is multiple dispatch: you can pass multiple SumType arguments to a single `match` call, and it will pass each of those SumTypes' values as a separate argument to the selected handler. If you're used to calling `match` with UFCS, the syntax for passing multiple arguments may take some getting used to. I recommend the following idiom: bool sameDimensions(Point p1, Point p2) { // Set up your handlers first alias doMatch = match!( (Point2D _1, Point2D _2) => true, (Point3D _1, Point3D _2) => true, (_1, _2) => false ); // Now make the actual call return doMatch(p1, p2); } Other improvements since 0.9.0, the last announced version: - SumTypes can be used as keys in associative arrays - isSumType!T is now true if T implicitly converts to a SumType - sumtype's license has been changed from MIT to Boost 1.0 - Member types with non-const `opEquals` overloads finally work correctly - Various other bug fixes and documentation improvements Links: - Documentation: https://pbackus.github.io/sumtype/sumtype.html - DUB: https://sumtype.dub.pm - Github: https://github.com/pbackus/sumtypeHello, Older version of sumtype accept this code: void main(){ import sumtype; alias Val = SumType!(bool); const bool b = true; Val val = b; //fail in newest version val = b; //fail in newest version } but new version need exact type: void main(){ import sumtype; alias Val = SumType!(bool); bool b = true; //cannot be const Val val = b; val = b; } is it bug in new version or old version?
Oct 27 2020
On Tuesday, 27 October 2020 at 16:26:10 UTC, vitamin wrote:Hello, Older version of sumtype accept this code: void main(){ import sumtype; alias Val = SumType!(bool); const bool b = true; Val val = b; //fail in newest version val = b; //fail in newest version } but new version need exact type: void main(){ import sumtype; alias Val = SumType!(bool); bool b = true; //cannot be const Val val = b; val = b; } is it bug in new version or old version?It's a bug in the new version. Thanks for reporting. I've opened an issue on Github for this: https://github.com/pbackus/sumtype/issues/47
Oct 27 2020