Hetu Script Generator

Reimplementation of hetu-script-autobinding: a build_runner generator that emits Hetu ↔ Dart bindings, targeting hetu_script 0.6. Powers the bindings of sfw (Script Flutter Widget).

Note: early stage of development, think carefully before using it in production.

Two modes

1. Annotation mode — for classes you own

import 'package:hetu_script_generator/annotations.dart';
import 'package:hetu_script/hetu_script.dart';

part 'person.g.dart';

@HetuExternalClass()
class Person { ... }

dart run build_runner build --delete-conflicting-outputs

Emits a PersonClassBinding extends HTExternalClass + htFetch/htAssign extension as a part file.

2. Config mode — for Flutter/SDK/3rd-party classes you cannot annotate

// lib/bindings/flutter_bindings.dart
import 'package:flutter/material.dart';
import 'package:hetu_script_generator/annotations.dart';

@HetuBindings(
  classes: [Text, Column, Container, EdgeInsets, Colors, MainAxisAlignment],
  skip: {Container: ['someMember']},
)
const flutterBindings = true;

The external_bindings builder emits TWO files next to the config:

• flutter_bindings.hetu.g.dart — standalone bindings plus a ready-to-register list: final List<HTExternalClass> generatedExternalClasses = [...]
• flutter_bindings.ht — the paired Hetu external class declarations with real parameter signatures (hetu validates call arguments against the declaration), ready to ship as a Flutter asset and import from scripts.

Generated bindings automatically:

• adapt function-typed parameters (HTFunction → typed Dart closure, e.g. VoidCallback, ValueChanged<bool>);
• coerce int → double parameters (hetu numbers arrive as int);
• rebuild List<T> parameters from script lists (List<Widget>.from(...));
• pick Dart-side default values correctly under hetu's argument normalization;
• skip operators, private members and Flutter diagnostics noise (plus per-class skip:).

Setup

dev_dependencies:
  build_runner: ^2.4.0
  hetu_script_generator:
    git: https://github.com/nikitafedorov008/hetu_script_generator

Scope the builder in your build.yaml to the config file:

targets:
  $default:
    builders:
      hetu_script_generator|external_bindings:
        generate_for:
          - lib/bindings/flutter_bindings.dart

Status: constructors (incl. named), static/instance members, enums, callback adapters, type coercions. See test/ for golden examples and ../sfw for a real consumer with a live-interpreter test suite.