A lightweight Dart library for describing self-contained, composable business logic through reactive units and effects.

• Installation
• Core Concepts
  • Modules
  • Events
  • Effects
  • Symantic
• Usage
• Architecture
• Contributing
• License

Add to your pubspec.yaml:

dependencies:
  sym: ^0.1.0

sym provides a way to describe business logic through composable, self-contained units called Modules that coordinate reactive Events and Effects.

Modules are self-contained units that group related logic and state. They define their public API and internal behavior:

final counter = Module(($) {
  final increment = $.trigger<()>();
  
  return (
    increment: increment,
    value: $.store<int>(($) {
      $.on(increment, (_) => $.self + 1); 
      return 0;
    })
  );
});

Events come in two flavors:

• Triggers - Stateless, callable events that signal something happened
• Stores - Stateful events that hold and update data

// Trigger example
final increment = $.trigger<()>();

// Store example 
final count = $.store<int>(($) => 0);

Effects define relationships between events through reactions:

$.on(increment, ($, _) async {
  await Future.delayed(Duration(seconds: 1));
  count($, count.value + 1);
});

The $ parameter provides a constrained API for defining acceptable operations in a given context:

Module(($) {
  // $ provides trigger(), store(), value(), on(), use()
});

See the example directory for complete examples.

sym is built on a few key principles:

• Modules are the unit of composition and encapsulation
• Events model both state changes and side effects
• Effects coordinate reactivity between events
• The Symantic ($) constrains operations to maintain integrity

This provides a flexible foundation for describing complex business logic in a maintainable way.

MIT License