d4rt 0.0.9

An interpreter and runtime for the Dart language. It allows you to execute Dart code dynamically, bridge native classes, and build advanced scripting or plugin systems in your Dart/Flutter applications

d4rt

d4rt (pronounced "dart") is an interpreter and runtime for the Dart language, written in Dart.
It allows you to execute Dart code dynamically, bridge native classes, and build advanced scripting or plugin systems in your Dart/Flutter applications.

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Features

• Dart interpreter: Run Dart code dynamically at runtime.
• Full generics support: Complete support for generic classes, functions, and type constraints with runtime validation.
• Type bounds checking: Enforce generic type constraints (e.g., T extends num) with dynamic resolution.
• Bridging system: Expose your own Dart/Flutter classes, enums, and methods to interpreted code.
• Async/await support: Handle asynchronous code and Futures.
• Class, enum, and extension support: Use most Dart language features, including classes, inheritance, mixins, enums, and extensions.
• Pattern matching: Support for Dart's pattern matching in switch/case and assignments.
• Runtime type validation: Validate generic type arguments and method parameters at runtime.
• Custom logging: Integrated, configurable logger for debugging interpreted code.
• Extensible: Add your own bridges for custom types and native APIs.

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Installation

Add to your pubspec.yaml:

dependencies:
  d4rt: # latest version

Then run:

dart pub get

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Usage Example

import 'package:d4rt/d4rt.dart';

void main() {
  final code = '''
    int fib(int n) {
      if (n <= 1) return n;
      return fib(n - 1) + fib(n - 2);
    }
    main() {
      return fib(6);
    }
  ''';

  final interpreter = D4rt();
  final result = interpreter.execute(source: code);
  print('Result: $result'); // Result: 8
}

Bridging Native Classes & Enums

You can expose your own Dart classes and enums to the interpreter using the bridge system. Here are minimal examples:

Bridge a Dart Class (Minimal)

import 'package:d4rt/d4rt.dart';

class MyClass {
  int value;
  MyClass(this.value);
  int doubleValue() => value * 2;
}

final myClassBridge = BridgedClassDefinition(
  nativeType: MyClass,
  name: 'MyClass',
  constructors: {
    '': (InterpreterVisitor visitor, List<Object?> positionalArgs, Map<String, Object?> namedArgs) {
      if (positionalArgs.length == 1 && positionalArgs[0] is int) {
        return MyClass(positionalArgs[0] as int);
      }
      throw ArgumentError('MyClass constructor expects one integer argument.');
    },
  },
  methods: {
    'doubleValue': (InterpreterVisitor visitor, Object target, List<Object?> positionalArgs, Map<String, Object?> namedArgs) {
      if (target is MyClass) {
        return target.doubleValue();
      }
      throw TypeError();
    },
  },
  getters: {
    'value': (InterpreterVisitor? visitor, Object target) {
      if (target is MyClass) {
        return target.value;
      }
      throw TypeError();
    },
  },
);

void main() {
  final interpreter = D4rt();
  interpreter.registerBridgedClass(myClassBridge, 'package:example/my_class_library.dart');

  final code = '''
    import 'package:example/my_class_library.dart';

    main() {
      var obj = MyClass(21);
      return obj.doubleValue();
    }
  ''';

  final result = interpreter.execute(source: code);
  print(result); // 42
}

Bridge a Dart Enum (Minimal)

import 'package:d4rt/d4rt.dart';

enum Color { red, green, blue }

final colorEnumBridge = BridgedEnumDefinition<Color>(
  name: 'Color',
  values: Color.values,
);

void main() {
  final interpreter = D4rt();
  interpreter.registerBridgedEnum(colorEnumBridge, 'package:example/my_enum_library.dart');

  final code = '''
    import 'package:example/my_enum_library.dart';

    main() {
      var favoriteColor = Color.green;
      print('My favorite color is \${favoriteColor.name}');
      return favoriteColor.index;
    }
  ''';

  final result = interpreter.execute(source: code);
  print(result); // 1
}

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Supported Features

Feature	Status / Notes
Classes & Inheritance	✅ Full support (abstract, inheritance, mixins, interfaces, sealed, base, final)
Enums	✅ Full support (fields, methods, static, named values, index, name)
Mixins	✅ Supported (declaration, application, on clause, constraints)
Extensions	✅ Supported (methods, getters, setters, operators)
Async/await	✅ Supported (async functions, await, Futures)
Pattern matching	✅ Supported (switch/case, if-case, destructuring, list/map/record patterns)
Collections (List, Map, Set)	✅ Supported (literals, spread, if/for, nested, null-aware, records)
Top-level functions	✅ Supported (named, anonymous, closures, nested)
Getters/Setters	✅ Supported (instance, static, extension, bridge)
Static members	✅ Supported (fields, methods, getters/setters, bridge)
Switch/case	✅ Supported (classic, pattern, default, fallthrough, exhaustive checks)
Try/catch/finally	✅ Supported (multiple catch, on/type, rethrow, stacktrace)
Imports	✅ Supported (URIs, show/hide clauses for libraries defined in sources)
Generics	✅ Full support (generic classes/functions, type constraints, runtime validation)
Operator overloading	⚠️ Partial (via extensions, not via class operator methods)
FFI	🚫 Not supported
Isolates	🚫 Not supported
Reflection/Mirrors	🚫 Not supported
Records	✅ Supported (positional, named, pattern matching)
String interpolation	✅ Supported
Cascade notation (..)	✅ Supported
Null safety	✅ Supported (null-aware ops, checks, patterns)
Type tests (is, as)	✅ Supported
Exception handling	✅ Supported (throw, rethrow, custom errors)

See the documentation for details and limitations.

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Limitations

• Operator overloading is partially supported (via extensions, not via class operator methods).
• Some advanced Dart features (isolates, FFI, mirrors) are not available.
• The interpreter is not a full Dart VM: some language features may behave differently.

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Documentation

• API Reference
• Bridging Guide
• Supported Features
• Examples

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Contributing

Contributions are welcome!
Feel free to open issues, suggest features, or submit pull requests.

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License

MIT License. See LICENSE.

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About the Name

d4rt is a play on the word "dart", using "4" as a stylized "A".
It is pronounced exactly like "dart".