Simple "Test and Set" Functor template to avoid working with naked variables.

TestAndSetFunctor.h

#pragma once

// Author: Dado, le Grand Fromage
// 
// The purpose of this extremely simple template class is to address situations like these:
//
// if ( MyVariable )
// {
// [...]
// 	MyVariable = false;
// }
//
// You don't want to play around with naked variables like if that's their only purpose.
// You can make them into a function, and precisely into a functor in this case
//
// The operator() will act as a switch returning the old value, so the code above will effectively become:
//
// if ( MyVariable() )
// {
// [...]
// }
// No need to reset the variable to false as that will be flip/flopped inside the operator() function
// By passing a parameter to the operator() function it will act as a "set"
// 
// MyVariable = true;
//
// MyVariable(true)
//
// The functor uses a default value of 0, so it might not be suitable for types that cannot be casted to that
// I might consider adding type traits Concepts, C++20 fashion.
//
// Warning: This code uses UnrealEngine Pascal BS coding standard, don't ask why, I'm already crying.

template <typename T>
class TTestAndSetFunctor
{
public:
	T operator()( T NewValue = T{0} )
	{
		T OrigValue = Value;
		Value = NewValue;
		return OrigValue;
	}
private:
	T Value=T{0};
};