ack_generator

Ack Generator

ack_generator emits extension types for top-level Ack schemas annotated with @AckType().

Overview

Write your schemas directly with the Ack fluent API, then annotate the schema variable or getter to generate a typed wrapper:

import 'package:ack/ack.dart';
import 'package:ack_annotations/ack_annotations.dart';

part 'user_schema.g.dart';

@AckType()
final userSchema = Ack.object({
  'name': Ack.string(),
  'email': Ack.string().email(),
});

Running dart run build_runner build generates an extension type such as:

extension type UserType(Map<String, Object?> _data)
    implements Map<String, Object?> {
  static UserType parse(Object? data) { ... }
  static SchemaResult<UserType> safeParse(Object? data) { ... }

  String get name => _data['name'] as String;
  String get email => _data['email'] as String;
}

Installation

dependencies:
  ack: ^1.0.0-beta.12-wip
  ack_annotations: ^1.0.0-beta.12-wip

dev_dependencies:
  ack_generator: ^1.0.0-beta.12-wip
  build_runner: ^2.4.0

Supported declarations

• Top-level schema variables
• Top-level schema getters

@AckType() is not supported on classes or instance members.

Supported schema shapes

• Ack.object(...)
• Primitive schemas such as Ack.string(), Ack.integer(), Ack.double(), Ack.boolean()
• Ack.list(...) and Set-like list wrappers
• Ack.literal(...), Ack.enumString(...), Ack.enumValues(...)
• Non-object transforms with explicit output types
• Ack.discriminated(...) when branches are top-level @AckType object schemas in the same library

For discriminated unions, Ack.discriminated(...) owns the discriminator property. Branch schemas normally omit the discriminator field; if they include it, that field must be Ack.literal(...) matching the branch key or Ack.enumString(...) containing the branch key. Boundary payloads must still include the discriminator key. Conflicting, broad, transformed/refined, and restrictive discriminator fields are rejected. Generated branches expose the exact branch literal, and generated subtype parse() / safeParse() methods validate through the union's effective branch.

Important limitations

• Ack.any() and Ack.anyOf() do not generate extension types.
• Inline anonymous object branches are rejected for typed generation. Extract them to a named top-level schema first.
• Nullable top-level schemas do not emit extension types.
• @AckType() requires static schema resolution for nested object references.

Build commands

dart run build_runner build --delete-conflicting-outputs
dart run build_runner watch

More information

• Root docs: ../../README.md
• Annotation package: ../ack_annotations/README.md
• Example package: ../../example/README.md