变函数变量

Question

当我按下一个按钮，一堆变量改变的时候，我想做它。

function BuyItem(price, quantity, pps, text, quantitytext)
    if(PixoosQuantity >= price) then
        PixoosQuantity = PixoosQuantity - price
        price = price * 1.1

        quantity = quantity + 1

        PixoosPerSecond = PixoosPerSecond + pps
        PixoosPerSecondDisplay.text = "PPS: " .. string.format("%.3f", PixoosPerSecond)
        PixoosQuantityDisplay.text = "Pixoos: " .. string.format("%.3f", PixoosQuantity)

        text.text = "Deck of playing cards\nPrice: " .. string.format("%.3f", price) .. " Pixoos"
        quantitytext.text = quantity
    end
end

这是一个在按下按钮时调用的函数：

function ButtonAction(event)
    if event.target.name == "DeckOfPlayingCards" then
        BuyItem(DeckOfPlayingCardsPrice, DeckOfPlayingCardsQuantity, DeckOfPlayingCardsPPS, DeckOfPlayingCardsText, DeckOfPlayingCardsQuantityText)
    end
end

我的问题是，为什么变量不变化？我试过放return price之类的，但还是没用.

Answer 1

通过值传递变量price，而不是传递以参考。这个构造在Lua中不存在，因此您需要解决它，例如使用返回值：

DeckOfPlayingCardsPrice, DeckOfPlayingCardsText, DeckOfPlayingCardsQuantityText = BuyItem(DeckOfPlayingCardsPrice, [...], DeckOfPlayingCardsText, DeckOfPlayingCardsQuantityText)

并正确返回预期值：

function BuyItem(price, quantity, pps, text, quantitytext)
    if(PixoosQuantity >= price) then
        [...]
    end
    return price, quantity, quantitytext
end

在Lua你可以返回多个结果。