lua (love2d): 函数应该没有结束

Posted 2023-03-28

【中文标题】lua (love2d): 函数应该没有结束

【英文标题】：lua (love2d): function supposedly missing an end

【发布时间】：2021-11-23 14:29:01

【问题描述】：

它说第 98 行的函数没有“结束”。我发誓没有遗漏的“结尾”，我一遍又一遍地验证，我找不到它是关于什么的。

错误

语法错误：main.lua:142: 'end' 预期（关闭 'function' 在 第 98 行）在 '' 附近

追溯

[C]：在 0x07f9a11328f0 [C]：在函数“要求”中 [C]：在函数中 'xpcall' [C]：在函数'xpcall'中

player = 
opponent = 
ball = 
screen =


function love.load()

    screen.top = 0
    screen.bottom = love.graphics.getHeight()
    screen.left = 0
    screen.right = love.graphics.getWidth()

    player.x = 50
    player.y = screen.bottom / 2
    player.width = 20
    player.height = 100
    player.speed = 500

    opponent.x = screen.right - 50
    opponent.y = screen.bottom / 2
    opponent.width = 20
    opponent.height = 100
    opponent.speed = 400

    ball.x = screen.right / 2 - 10
    ball.y = screen.bottom / 2 - 10
    ball.width = 20
    ball.height = 20
    ball.speed = 200
    ball.xVel = -ball.speed
    ball.yVel = 0

end


function love.update(dt)

    player.move(dt)

    opponent.move(dt)

    ball.move(dt)
    ball.collide(dt)

end


function love.draw(dt)

    player.draw()

    opponent.draw()

    ball.draw()

end


function checkCollision(a, b)

    if a.x + a.width > b.x and a.x < b.x + b.width and a.y + a.height > b.y and a.y < b.y + b.height then
        return true
    else
        return false
    end

end


function player.draw()

    love.graphics.rectangle('fill', player.x, player.y, player.width, player.height)

end
function player.move(dt)

    if love.keyboard.isDown('w') then
        player.y = player.y - player.speed * dt
    elseif love.keyboard.isDown('s') then
        player.y = player.y + player.speed * dt
    end

    if player.y < screen.top then
        player.y = screen.top
    elseif player.y + player.height > screen.bottom then
        player.y = screen.bottom - player.height
    end

end


function opponent.draw()

    love.graphics.rectangle('fill', opponent.x, opponent.y, opponent.width, opponent.height)

end
function opponent.move(dt)

    if ball.y + ball.height < opponent.y then
        opponent.y = opponent.y - opponent.speed
    else if ball.y > opponent.y + opponent.height then
        opponent.y = opponent.y + opponent.speed
    end

    if opponent.y < screen.top then
        opponent.y = screen.top
    elseif opponent.y + opponent.height > screen.bottom then
        opponent.y = opponent.bottom - opponent.height
    end

end


function ball.draw()

    love.graphics.rectangle('fill', ball.x, ball.y, ball.width, ball.height)

end
function ball.move(dt)

    ball.x = ball.x + ball.xVel * dt
    ball.y = ball.y + ball.yVel * dt

    if ball.y < screen.top then
        ball.y = screen.top
        ball.yVel = -ball.yVel
    elseif ball.y + ball.height > screen.bottom then
        ball.y = screen.bottom
        ball.yVel = -ball.yVel
    end
end
function ball.collide(dt)

    if checkCollision(ball, player) then
        ball.xVel = -ball.xVel
        local middleBall = ball.y + (ball.height / 2)
        local middlePlayer = player.y + (player.height / 2)
        local collisionPosition = middleBall - middlePlayer
        ball.yVel = collisionPosition
    end
end

【问题讨论】：

顺便说一句，你可以用return boolean（checkCollision()）代替if boolean then return true else return false end

【参考方案1】：

我将它粘贴到 vi 中并突出显示语法，并在 opponent.move(dt) 上第一眼看到，很明显缺少蓝色 end 来关闭功能块。 但我不想决定缺少的end 属于哪个if 更正它。 哎呀，现在我明白了。 你做一个else if 而不是：elseif