AcediaCore/docs/api.md

Acedia's API

Acedia's API is our way of solving the problem of adding new global functions. Examples of global functions are Log(), Caps(), Abs(), VSize() and a multitude of others that you can call from anywhere in UnrealScript. They can be accessed from anywhere because they are all declared as static methods inside Object - a base class for any other class. Problem is, since we cannot add our own methods to the Object, then we also can't add new global functions. The best we can do is declare new static methods in our own classes, but calling them would be cumbersome: class'glb'.static.DoIt().

Idea that we've used to solve this problem for Acedia is to provide every single Acedia object with an instance of a class that would contain all our global functions. We save an instance of this class in a local variable _, which allows us to simply write _.DoIt().

In actuality we don't just dump all of Acedia's global functions into one object, but group them into different APIs that can be accessed through _ variable:

_.text.FromString("I am here!");        // Text API
_.alias.ResolveColor("blue");           // Alias API
_.collections.EmptyDynamicArray();      // Collections API
_.memory.Allocate(class'SimpleSignal'); // Memory API

_ can't be accessed in static methods, since only default values are available in them. Since writing default._ would also be bulky, AcediaObject and AcediaActor provide a static method public static final function Global __() that is always available:

__().text.FromString("I am here!");
__().alias.ResolveColor("blue");
__().collections.EmptyDynamicArray();
__().memory.Allocate(class'SimpleSignal');

Any class you make that derives from either AcediaObject or AcediaActor will have _ and __() defined. If you need to create a class that does not derive from Acedia's classes, but you want to make Acedia's API be available inside it, then you simply need to redefine _ and __():

var Global _;

public static final function Global __()
{
    return class'Global'.static.GetInstance();
}

// ...
// Set `_`'s value somewhere before using your class:
_ = class'Global'.static.GetInstance();