在PHP中重构闭包/匿名函数

Question

是否可以从这样的代码中重构匿名函数：

function foo($path, $callback) {
    $callback();
}

$app = array('a', 'b', 'c');

foo('vehicle/:id', function() use ($app) {
    echo $app[0];
});

我尝试了这个，但它没有回应任何东西：

function foo($path, $callback) {
    $callback();
}

$vehicleCallback = function() use ($app) {
    echo $app[0];
};

$app = array('a', 'b', 'c');

foo('vehicle/:id', $vehicleCallback);

其他变体给了我语法错误。我希望将这些函数移动到一个单独的文件中，如果这很重要的话。

这是我的最终目标

callbacks.php

$cb1 = function () use ($app) {
    // things
};

$cb2 = function () use ($app) {
    // things
};

// ...more callbacks

router.php

require 'callbacks.php';

$app = new \Foo();

// code that might possibly manipulate $app

$app->bar('/some/relative/path/:param1', $cb1);
$app->bar('/another/relative/path', $cb2);

// possibly more code that mutates $app and then more callbacks

Answer 1

你一定要开启error_reporting：

  

注意：未定义的变量：第6行的应用程序

当您移动线路时：

$app = array('a', 'b', 'c');

在您的脚本开头，您将获得结果a

修改

您可以这样使用$app：

<?php

function foo($path, $callback, $app) {
    $callback($app);
};

$vehicleCallback = function($app) {
    echo $app[0];
};

$app = array('a', 'b', 'c');

foo('vehicle/:id', $vehicleCallback, $app);

<强> EDIT2

您班级的示例代码

<?php

$cb1 = function ($app, $path) {
    // things
    $app->display('cb1 '.$path.'<br />');
};

$cb2 = function ($app, $path) {
    // things
    $app->display('cb2 '.$path);
};


class Foo {
    public function display ($string) {
        echo strtoupper($string);
    }

    public function bar ($path, $closure) {
        $closure($this, $path);
    }
}


$app = new \Foo();

// code that might possibly manipulate $app

$app->bar('/some/relative/path/:param1', $cb1);
$app->bar('/another/relative/path', $cb2);

// possibly more code that mutates $app and then more callbacks