Chickensoft.Collections 1.5.0-godot4.3.0-beta.1

Chickensoft Collections

Lightweight collections, utilities, and general interface types to help make maintainable code.

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Install

dotnet add package Chickensoft.Collections

Map

A typed facade over OrderedDictionary. Provides a basic mechanism to store strongly typed keys and values while preserving key insertion order.

  var map = new Map<string, int>() {
    ["b"] = 2,
    ["a"] = 1,
  };

  map.Keys.ShouldBe(["b", "a"]);

Set and IReadOnlySet

For whatever reason, netstandard does not include IReadOnlySet. To workaround this, we've provided our own version of IReadOnlySet and a Set implementation that simply extends HashSet and adds the interface to it.

AutoProp

AutoProp allows you to make observable properties in the style of IObservable, but is implemented over plain C# events and modifies the API to be more ergonomic, a la Chickensoft style.

AutoProps are basically a simplified version of a BehaviorSubject that only updates when the new value is not equal to the previous value, as determined by the equality comparer (or the default one if you don't provide one). They operate synchronously and make guarantees about the order of changes in a very simple, easy to reason about manner.

using Chickensoft.Collections;

public class MyObject : IDisposable {
  // Read-only version exposed as interface.
  public IAutoProp<bool> MyValue => _myValue;

  // Read-write version.
  private readonly AutoProp<bool> _myValue = new AutoProp<bool>(false);

  public void Update() {
    // Update our values based on new information.
    _myValue.OnNext(true);

    // ...

    // Check the latest value.
    if (_myValue.Value) {
      // ...
    }

    // Subscribe to all future changes, **AND** get called immediately with the
    // current value.
    _myValue.Sync += OnMyValueChanged;

    // Subscribe to all future changes.
    _myValue.Changed += OnMyValueChanged;

    // Subscribe to completed
    _myValue.Completed += OnMyValueCompleted;

    // Subscribe to errors
    _myValue.Error += OnMyValueError;

    // Optional: inform completed listeners we're done updating values
    _myValue.OnCompleted();

    // Optional: send error listeners an error value
    _myValue.OnError(new System.InvalidOperationException());

    // ...

    // Always unsubscribe C# events when you're done :)
    _myValue.Sync -= OnMyValueChanged;
    _myValue.Changed -= OnMyValueChanged;
    _myValue.Completed -= OnMyValueCompleted;
    _myValue.Error -= OnMyValueError;

    // Or clear all subscriptions at once:
    _myValue.Clear();

    // When your object is disposing:
    _myValue.Dispose();
  }

  private void OnMyValueChanged(bool value) { }
  private void OnMyValueCompleted() { }
  private void OnMyValueError(Exception err) { }

  // ...
}

• ✅ Uses plain C# events.

  Observers are called one-at-a-time, in-order of subscription, on the invoking thread, and synchronously (and will always be that way unless Microsoft tampers with the underlying Multicast delegate implementation that powers C# events).

  Chickensoft prefers to keep everything synchronous and deterministic in game development, only adding parallelization or asynchronicity where it's absolutely necessary for performance. Otherwise, simpler is better.

• ✅ Familiar API.

  If you've ever used IObservable and/or BehaviorSubject, you basically already know how to use this.

• ✅ Guarantees order of events and allows updates from handlers.

  If you change the value from a changed event handler, it will queue up the next value and process it synchronously afterwards. This allows it to pass through each desired value, guaranteeing callbacks will be called in the correct order for each value it passes through.

• ✅ Doesn't update if the value hasn't changed.

Blackboard

A blackboard datatype is provided that allows reference values to be stored by type. It implements two interfaces, IBlackboard and IReadOnlyBlackboard.

var blackboard = new Blackboard();

blackboard.Set("string value");
var stringValue = blackboard.Get<String>();

blackboard.Set(new MyObject());
var myObj = blackboard.Get<MyObject>();

// ...and various other convenience methods.

EntityTable

The EntityTable<TId> is a simple wrapper over a ConcurrentDictionary that is provided to help you conveniently associate any type of value with an identifier. Table entries are requested by their identifier and type. If the value exists and matches the requested type, it is returned. Otherwise, null is returned.

var table = new EntityTable<int>();

table.Set(42, "dolphins");

// Use pattern matching for an optimal experience.
if (table.Get<string>(42) is { } value) {
  Console.WriteLine("Dolphins are present.");
}

table.Remove(42);

A default implementation that uses string is also provided:

var table = new EntityTable();

table.Set("identifier", new object())

if (table.Get<object>("identifier") is { } value) {
  Console.WriteLine("Object is present.");
}

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