Function grafting

This hack allows you to add functions to an existing class without subclassing it. Useful for fixing broken/incomplete features.

Author: aizome8086

BarRat.uc

class BarRat extends Rat;

var string SecretCode;

/* HACK: The final modifier prevents a crash caused by looking up
function names at runtime. DO NOT REMOVE!!! */

final function SetSecretCode(string NewCode)
{
    SecretCode = NewCode;
}

FooRat.uc

class FooRat extends Rat;

var const private string SecretCode;

function EnterSecretCode(string Code)
{
    if(Code == SecretCode)
    {
        Log("Secret code entered!");
    }
    else
    {
        Log("Invalid code entered!");
    }
}

defaultproperties
{
    SecretCode="Swiss cheese"
}

TestRat.uc

class TestRat extends Rat;

struct Empty {};

struct FooRatRef extends Empty
{
    var FooRat Value; 
};

final function BarRat CastFooRatToBarRat(FooRat FooRat)
{
    local FooRatRef FooRatRef;
    local Empty Empty;
    local BarRat Result;

    FooRatRef.Value = FooRat;

    /* HACK: This assignment overflows the contents of FooRatRef.Value onto
    the local variable buffer, causing Result to hold a reference to FooRat. */

    Empty = FooRatRef;

    return Result;
}

event PostBeginPlay()
{
    local FooRat FooRat;
    local BarRat BarRat;

    super.PostBeginPlay();

    FooRat = Spawn(class'FooRat');
    BarRat = CastFooRatToBarRat(FooRat);

    FooRat.EnterSecretCode("cheese");
    BarRat.SetSecretCode("cheese");
    FooRat.EnterSecretCode("cheese");
}