CGPoint+Move.swift

extension CGPoint {

    mutating func move(x:Int? = nil, y:Int? = nil) -> CGPoint {
        if let i = x {
            self.x += CGFloat(i)
        }
        
        if let i = y {
            self.y += CGFloat(i)
        }
        
        return self
    }
    
    mutating func up(y:Int) -> CGPoint {
        return move(y: -y)
    }
    
    mutating func down(y:Int) -> CGPoint {
        return move(y: y)
    }
    
    mutating func left(x:Int) -> CGPoint {
        return move(x: -x)
    }
    
    mutating func right(x:Int) -> CGPoint {
        return move(x: x)
    }
}

I like the idea but anyway here is a bit cleaner version of it

extension CGPoint {

    mutating func move(x:CGFloat? = nil, y:CGFloat? = nil) -> CGPoint {
        if let x = x {
            self.x += x
        }

        if let y = y {
            self.y += y
        }

        return self
    }

    mutating func up(y:CGFloat) -> CGPoint {
        return move(y: -y)
    }

    mutating func down(y:CGFloat) -> CGPoint {
        return move(y: y)
    }

    mutating func left(x:CGFloat) -> CGPoint {
        return move(x: -x)
    }

    mutating func right(x:CGFloat) -> CGPoint {
        return move(x: x)
    }
}