https://github.com/werediver/sum_types.dart

A code generator enabling sum-types in Dart
https://github.com/werediver/sum_types.dart

algebraic-data-types code-generation dart flutter sum-types

Last synced: 2 days ago
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A code generator enabling sum-types in Dart

• Host: GitHub
• URL: https://github.com/werediver/sum_types.dart
• Owner: werediver
• License: mit
• Created: 2019-08-19T19:43:49.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2024-11-12T16:05:56.000Z (12 months ago)
• Last Synced: 2025-01-29T09:25:25.910Z (9 months ago)
• Topics: algebraic-data-types, code-generation, dart, flutter, sum-types
• Language: Dart
• Size: 119 KB
• Stars: 40
• Watchers: 2
• Forks: 7
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

          
[![Build Status](https://travis-ci.com/werediver/sum_types.dart.svg?branch=master)](https://travis-ci.com/werediver/sum_types.dart)

[![sum_types version](https://img.shields.io/pub/v/sum_types?label=sum_types)](https://pub.dev/packages/sum_types)

[![sum_types_generator version](https://img.shields.io/pub/v/sum_types_generator?label=sum_types_generator)](https://pub.dev/packages/sum_types_generator)

## sum_types and sum_types_generator

[sum_types](https://pub.dev/packages/sum_types) and [sum_types_generator](https://pub.dev/packages/sum_types_generator) packages together define a code generator enabling [sum-types](https://en.wikipedia.org/wiki/Sum_type) in Dart.

NOTE: v0.2.0 is a major update with backward-incompatible [changes](CHANGELOG.md#020).

## Example

In [example/lib/src/](example/lib/src) you can find a few sum-type declarations and the code generated for them.

This one models the natural numbers (with zero):

```dart

import 'package:meta/meta.dart';

import 'package:sum_types/sum_types.dart';

@SumType()

class Nat extends _$Nat {

  const Nat.zero() : super(zero: const Unit());

  const Nat.next(Nat value) : super(next: value);

  Nat operator +(Nat other) => this.iswitch(

        zero: () => other,

        next: (next) => Nat.next(next + other),

      );

  int toInt() => this.iswitch(

        zero: () => 0,

        next: (next) => 1 + next.toInt(),

      );

}

```

## Features

Core:

- [x] Const case-constructors (`const Nat.zero()`)

- [x] Extensible sum-types (`Nat.toInt()`)

- [x] Nested sum-types

- [x] Recursive sum-types (`Case<_Nat>(name: "next")` → `Nat.next(Nat.zero())`)

- [x] Generic sum-types (`Either`)

- [x] Exhaustive in-line `iswitch`

- [x] Inexhaustive in-line `iswitcho` (with `otherwise:` case)

Sugar:

- [x] No-payload cases (`Case(name: "zero")` → `Nat.zero()`)

- [x] Default case-names (`Case()` → `JSON.string("some")`)

Trivia:

- [x] Equality test

- [x] Hash function

- [x] To string conversion

Serialization-deserialization support through product-types interoperability:

- [x] Deserialization support (`NatRecord`, `Nat.load>(T rec)`)

- [x] Serialization support (`Nat.dump(T Function({Unit zero, T next} make))`)

## Development

Find the upcoming development plans in the [project planner](https://github.com/werediver/sum_types.dart/projects/1).